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Health and Disease Biomedical Research Neuroscience

Dissociative Identity Disorder: Exploring the Reality Behind Having Multiple Personalities

Introduction

Multiple personality disorder is the term that was previously used to describe what is now known as dissociative identity disorder (DID). This is a psychological condition which the brain instigates as a method of self-preservation and is often the result of prolonged and habitual abuse. DID is, according to WebMD, “a severe form of dissociation”1 where an individual becomes mentally disconnected from their thoughts, memories, and even their self-identity. Although severe, this is one way that the human body tries to protect itself from traumatic and difficult situations – by shutting the primary consciousness away and creating other consciousnesses to deal with the present trauma. When each alteration is in control of the individual’s body, this is referred to as fronting. According to the American Psychiatric Association2, approximately 90% of those in Europe, Canada, and the United States suffering from DID have experienced abuse and neglect during childhood. Sufferers of DID have at least two separate and distinct personalities or consciousnesses, and the other personalities cannot remember what happened when they were not the fronting consciousness.

DID is an example of a dissociative disorder, and sufferers of such disorders perpetually feel disconnected from their reality. Approximately 2% of the US population have dissociative disorders3, and women are more likely to have such conditions than men. The three primary dissociative disorders are dissociative identity disorder (DID), derealisation disorder, and dissociative amnesia. Post-traumatic stress disorder (PTSD) and acute stress disorder share similar symptoms with dissociative disorders – including memory loss and depersonalization – but are not considered to fully be dissociative disorders in their own right.

An article published in the International Journal of Social Psychiatry4 entitled “Dissociative Disorders in a Psychiatric Institution in India – a Selected Review and Patterns over a Decade” discusses research into DID. The purpose of this study was to examine patterns of DID sufferers across ten years and included inpatients and outpatients who attended a psychiatric hospital between the years 1999 and 2008. The research discovered that between 1.5 and 15.0 per 1,000 outpatients were diagnosed with DID, while between 1.5 and 11.6 per 1,000 of the inpatients were diagnosed. This review concluded by stating that “dissociative motor disorder and dissociative convulsions are the most common disorders” and that DID is especially under-diagnosed outside of Western regions.

What Causes DID?

Although there is no single definitive cause of DID, the main factor for this condition is severe and repeated abuse – including physical, emotional, and sexual abuse. This abuse often will begin in childhood, and, compounded with the fact that the child often does not have a safe refuge from such abuse because it is typically, though not always, carried out by a family member, can cause the child to develop DID. In rarer cases, a person can develop DID due to experiencing a violent and traumatic event, such as living in a combat zone.

Signs and Symptoms

For a person to be categorized as having DID, they have to have at least two distinct personalities. The predominant identity of the individual is known as the ‘core’ identity, and the personalities created are the ‘alters’5. Someone with DID can have many alters, possibly over 100. These alters, if there are many, tend to vary in age, gender, ethnicities, and characters even within a single person – and for some people with DID their alters are able to interact with one another.

The main symptom of DID is sudden and involuntary transitions between these alters. As a result, this can mean that the core identity has many long-term gaps in their memory, as they can only remember details from when they are fronting. Self-harm and suicide attempts are unfortunately very prevalent amongst DID sufferers, and over 70% of outpatients with DID have attempted suicide at least once3.

6Some common symptoms of DID include sudden flashbacks, feeling detached from one’s own body/out-of-body experiences, hallucinations, and inability to be aware of one’s surroundings – for example, finding yourself in a place with no memory of how you got there. Long periods of memory loss are also typical for DID sufferers, and this is known as dissociative amnesia – which is a type of memory loss that is greater than forgetfulness. Dissociative fugue is an episode of amnesia that can cause the person to not remember personal information or to experience emotional detachment7. In addition to these symptoms of DID, sufferers of this condition may also endure mood swings, anxiety, panic attacks, unexplained phobias, insomnia, night terrors, migraines, severe pain anywhere on the body, sexual dysfunction, and the increased likelihood of developing eating disorders.

Not only does DID cause intense emotional and psychological difficulty for an individual with the condition, but also it can physically change the brain. A paper published in The American Journal of Psychiatry8 examined the results of a study involving 38 women. Fifteen (15) of these women had DID, while the other 23 did not have DID, nor any other psychiatric condition. Each woman underwent MRI scanning to measure the volumes of their hippocampus, which controls memory, and amygdala, which controls emotions. The results were compared between these two groups and showed that the volume of the hippocampus was 19.2% smaller for those with DID. The volume of the amygdala was 31.6% smaller in the DID patients too. Overall, this suggests that people with DID will generally have a lower hippocampal and amygdalar volume compared to people who do not have DID. This leads to impacts on memory and emotions, which is common for sufferers of DID – who typically have long periods of memory loss or significant gaps in their memory, in addition to frequent mood swings and swiftly changing emotions.

In a paper published in the National Library of Medicine9, a study was carried out to measure hippocampal volume in 21 women who had been severely sexually abused during childhood, as well as 21 women who had not previously been abused. Again, magnetic resonance imaging (MRI) was used to determine the hippocampal volume for each of the 42 women, and the results of this study showed that the left-sided hippocampal volume was, on average, 5% smaller in the women who were sexually abused compared to the women who had not been. While the same test was carried out on the right-sight hippocampus for each woman, the article states, “hippocampal volume was also smaller on the right side, but this failed to reach statistical significance.” The results of this study show how abuse – of any kind, but in this research, it was specifically sexual abuse – can physically damage the brain, as it tries to protect the individual by having extensive gaps in their memory. As discussed previously, sustained abuse can cause DID to manifest in the individual, as sufferers of this condition present with similar changes to the hippocampal volume.

Intervention and Treatment

Like other psychological conditions, there is no cure for DID, but there are several treatment methods that have proved effective. Treatment for DID can take several years, and the most common method is psychotherapy. Throughout this process, the aim is to work with the patient so that their individual alters can merge to form a single, cohesive identity5. This is an arduous process, as it involves the patient working through the trauma and/or abuse that caused them to develop DID in the first place. Family therapy can also be helpful for sufferers of DID, as it can educate friends and family members about the difficulties of living with DID and how best to support that person. Less frequently, clinical hypnosis can be used as a possible treatment method for DID, in which patients can access repressed memories that they experienced as one of their alters and so cannot remember when any other alter is fronting6. Furthermore, cognitive behavioral therapy is another commonly used method in an attempt to treat DID.

Misdiagnosis

The American Psychiatric Association led a question-and-answer panel with an expert of psychiatry: Dr. David Spiegel, Professor and Associate Chair of Psychiatry & Behavioural Sciences at Stanford University School of Medicine10. When he was asked the question, “are people with dissociative identity disorder often misdiagnosed?” Dr. Spiegel said: “they are sometimes misdiagnosed as having schizophrenia. Another common misdiagnosis is borderline personality disorder.” Later in the article, Dr. Spiegel says, “typically those with dissociative identity disorder experience symptoms for six years or more before being correctly treated.” This shows not only how difficult it is to acquire treatment but, even when treatment is given it can frequently be based on a misdiagnosis. If a person with DID is misdiagnosed as having schizophrenia, they may be prescribed antipsychotic medications, and their emotions will be dulled when they take this. This will lead to further increases in this antipsychotic medication on the belief that it is an effective treatment for the individual. Dr. Spiegel remarks that “dissociation is a common coping mechanism,” saying that “many rape victims experience the crime as though they were floating above their bodies.” While dissociation is a natural human response to a traumatic event, it is when this trauma is sustained and repeated that this dissociation can develop into DID.

Individuals’ Stories

Jeni Haynes is a woman who has DID and has over 2500 distinct personalities/alters – though only six predominant ones. Jeni developed DID due to her intensely traumatic childhood, where she was subjected to horrific physical and sexual abuse from her father, Richard Haynes. In the trial against Richard Haynes for this abuse, Jeni testified through her multiple personalities, allowing each one to front her in turn. After the core personality of Jeni Haynes, there was Symphony, a four-year-old girl who endured much of the abuse – and described by Jeni to be her most significant alter. Jeni addressed the court, telling them: “Symphony intended to testify in court for the whole thing. When my father raped Jennifer Haynes, he raped Symphony.” Jeni’s other alters included an eleven-year-old boy called Judas and a 17-year-old boy called Muscles11. This trial was the first trial in Australia where an individual was allowed to provide evidence through their alters. While Richard Haynes was convicted, that does not mean that Jeni has a normal life now. Her DID causes her struggle every day, and in her victim impact statement, she said, speaking about her and all of her different alters: “we have to hide our multiplicity and strive for a consistency in behavior. Having 2,500 different voices, opinions and attitudes is extremely hard to manage”12.

Another example of an individual’s struggle with DID is that of a 25-year-old soldier. In an article written by the American Psychiatric Association13, she is referred to only as “Sandra”, which is a pseudonym to maintain confidentiality. Sandra was hospitalized due to her sudden behavioral changes and episodes of acute memory loss. As she underwent clinical hypnosis, it was discovered that she had a series of significantly large gaps in her memory, and she was also found to have swift and severe changes in her emotions. She then began to have psychotherapy, where she worked through the memories of sexual abuse she had endured since the age of 11. Sandra was diagnosed with DID, and now she continues to have psychotherapy as well as take anti-depressants. She reportedly rarely dissociates and has now been able to establish stable relationships.

Conclusion

To conclude, dissociative identity disorder (DID) is a psychiatric condition that can present immense difficulty to those with it, as they can feel completely disconnected from their surroundings – and it can be terrifying when individuals cannot remember what has happened to them and feel like they do not have autonomy over their own body. Furthermore, DID is hugely underdiagnosed or misdiagnosed and can mean that the treatment people need – which is already a lengthy process of many years at least – is delayed. There needs to be more information about DID, as some do not believe it is even an actual condition. Educating people about DID can mean that they can recognize if their friends or families show signs of this condition and can potentially aid them to attain treatment and support faster than if they waited to do so themselves.

Samara Macrae, Youth Medical Journal 2022

References

1.   WebMD: “Dissociative Identity Disorder (Multiple Personality Disorder) – https://www.webmd.com/mental-health/dissociative-identity-disorder-multiple-personality-disorder

2.   American Psychiatric Association: “What Are Dissociative Disorders?” – https://www.psychiatry.org/patients-families/dissociative-disorders/what-are-dissociative-disorders

3.   Cleveland Clinic: “Dissociative Disorders” – https://my.clevelandclinic.org/health/diseases/17749-dissociative-disorders-

4.   International Journal of Social Psychiatry: “Dissociative Disorders in a Psychiatric Institution in India – a Selected Review and Patterns over a Decade” – https://journals.sagepub.com/doi/abs/10.1177/0020764009347335

5.   Cleveland Clinic: “Dissociative Identity Disorder (Multiple Personality Disorder)” – https://my.clevelandclinic.org/health/diseases/9792-dissociative-identity-disorder-multiple-personality-disorder

6.   American Association for Marriage and Family Therapy: “Dissociative Identity Disorder” – https://aamft.org/Consumer_Updates/Dissociative_Identity_Disorder.aspx

7.   Healthline: “Dissociative Identity Disorder” – https://www.healthline.com/health/dissociative-identity-disorder

8.   The American Journal of Psychiatry: “Hippocampal and Amygdalar Volumes in Dissociative Identity Disorder” – https://ajp.psychiatryonline.org/doi/full/10.1176/ajp.2006.163.4.630

9.   National Library of Medicine: “Hippocampal volume in women victimised by childhood sexual abuse” – https://pubmed.ncbi.nlm.nih.gov/9234472/

10.   American Psychiatric Association: “Expert Q&A: Dissociative Disorders” – https://www.psychiatry.org/patients-families/dissociative-disorders/expert-q-and-a

11.   The Sydney Morning Herald: “Woman to use multiple personalities in evidence against abusive father” – https://www.smh.com.au/national/woman-to-use-multiple-personalities-in-evidence-against-abusive-father-20190301-p51156.html

12.   BBC News: “Dissociative Identity Disorder: The woman who created 2,500 personalities to survive” – https://www.bbc.co.uk/news/world-australia-49589160

13.   American Psychiatric Association: “Patient Story: Dissociative Disorders” – https://www.psychiatry.org/patients-families/dissociative-disorders/patient-story

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Health and Disease

The 10/90 Gap and Its Impact on Malaria

By Samara Macrae

Published 11:18 EST, Thurs October 21st, 2021

Introduction:

Epidemic is defined by the Oxford English Dictionary as: “a widespread occurrence of an infectious disease in a community at a particular time”. Malaria is classed as an epidemic, currently affecting over 100 countries predominantly in the tropical regions – and is the fourth highest cause of death in children under the age of five years1. Despite the extensive death and casualty toll, as well as the havoc wreaked on socio-economic conditions in areas of outbreak, these epidemics receive significantly less media coverage and humanitarian attention as they are affecting the developing world. Even after the original health threat has been managed, developing countries continue to face serious long term effects compared to more economically developed ones.  This can be shown by what activists refer to as the ‘10/90 Gap’: this is the idea that only 10% of global health research is allocated towards diseases responsible for 90% of preventable deaths globally. Diseases that make up this 10% can be referred to as ‘neglected diseases’, typically because they predominantly affect lower-income countries where poverty and malnutrition are rife – and so exacerbate the spread of such life-threatening communicable diseases. According to the World Health Organisation, 45% of the ‘disease burden’ in the most under-developed and poorest countries is derived from poverty. Therefore, these diseases cannot merely be treated medically, but the deeper social problems in the regions need to be tackled as well.

Malaria is an example of a disease which can be understated and disregarded for its impact due to societal prejudice against less economically developed regions of the world. Malaria mostly affects tropical regions, including (but not limited to) large zones of Africa, particularly in sub-Saharan Africa, South America, the Dominican Republic, the Caribbean and Central America2. While there are recorded cases of malaria in developed countries such as the USA and the UK, this is almost exclusively the result of travellers returning from holiday from countries where malaria is prevalent. 3Malaria disproportionately affects the continent of Africa and, in 2019, 94% of malaria cases and deaths as a result of this disease were in the African continent. Nearly 50% of the global population was at risk of contracting malaria in 2019, and that same year there were approximately 229 million recorded cases of the disease across the world. Despite the fact that malaria is both curable and preventable, this disease has significantly less funding compared to diseases and conditions which disproportionately affect the developed world – such as obesity, which is the fifth most important risk factor for disease amongst developed countries. In 1986, the US spent approximately $39 billion on tackling obesity, and this rose to $190 billion by 20054.

How malaria affects the body:

Malaria is caused by a plasmodium, and there are five different parasite species which can spread malaria – the two most predominant species being P. falciparum and P. vivax3. The former is the main cause of malaria in Africa, south-east Asia, and the Pacific while the latter presents the greater threat in South and Central America. These species of plasmodium parasite are transmitted by an animal vector: the female Anopheles mosquito. In rarer instances, malaria can be transmitted by sharing unsterilised needles, via blood transfusion or from the mother to the foetus. When the female Anopheles mosquito takes a blood meal from a host who is infected with malaria, it will inject saliva into the host’s skin while sucking blood through its proboscis. This saliva acts as a form of antiseptic and is why it is difficult to notice when the mosquito is doing this. As the mosquito takes up this infected blood, the male and female gametes of the malaria-causing plasmodium will fuse in the mosquito’s stomach. Cell division will be carried out then, which will lead to the formation of thousands of immature malarial parasites – these parasites will then invade the salivary glands of the mosquito. This means that when the mosquito takes a blood meal from an uninfected host, it will inject its saliva – containing the plasmodium parasites – into the host’s skin. Thus, the parasites are then able to infect the host’s bloodstream and this results in the manifestation of the disease. One reason why the majority of malaria cases and deaths are in the continent of Africa is due to the long lifespan of the African vector species of female Anopheles mosquitoes. This means that the parasite has a longer time to develop inside the mosquito, and so more parasites can be produced. 

Symptoms:

3The symptoms of malaria typically show 10 to 15 days after an individual is bitten by a mosquito vector. Some early symptoms can include a headache, fever, and chills – but these are all typically mild and so not necessarily immediately discernible as malaria. However, the severity of the disease soon increases, as failure to receive treatment within 24 hours of the first symptoms when infected by the P. falciparum parasite can mean that the disease progresses swiftly and often culminates in death. Severe cases of malaria can also include the following symptoms: severe anaemia, liver damage and multiple-organ failure. Children are the group most greatly affected by malaria, especially under the age of five years – and in 2019, 67% of all malaria deaths globally (approximately 274 000 people) were children below five years of age. Other high-risk groups of people are pregnant women, non-immune migrants/travellers and individuals with HIV or AIDS.

Prevention:

As malaria is transmitted by mosquito vectors, the most straightforward and accessible method of prevention is mosquito nets – which can be made more effective if treated with insecticide. This, in conjunction with personal use of insect repellent has been shown to reduce the risk of malarial infection by up to 80%5. Also, wearing clothing that limits skin exposure can help to reduce the chance of receiving a mosquito bite which could potentially be fatal. Individuals who are travelling to countries where there are cases of malaria can obtain medication to prevent them contracting the disease. 

Malarial chemoprophylaxis is only available in European countries, and only for travellers to countries where malaria is prevalent – and not for the inhabitants of the areas affected6. Malarial chemoprophylaxis is classified into 3 groups in order to determine the most suitable drug for the individual. The drug recommended depends on factors such as duration of potential exposure, age, and climate of the destination.7 Antimalarial tablets can reduce the chances of becoming infected with malaria by approximately 90%. The main types of antimalarial medication are: atovaquone plus proguanil, doxycycline, mefloquine/larium and chloroquine plus proguanil. Chloroquine plus proguanil is still available for travellers but is rarely recommended now due to its ineffectiveness against P. falciparum but can still be prescribed if the individual is visiting an area where this plasmodium is less common, as in Sri Lanka. 

Recently, there has been promising research into a new malaria vaccine, developed at the University of Oxford’s Jenner Institute. In a small clinical trial, involving 450 children, this vaccine showed up to 77% efficacy – a dramatic increase from the current vaccine’s efficacy8. Undoubtedly larger clinical trials are needed to ensure the safety and effectiveness of this vaccine, but surely this research should be pushed ahead – as the Covid-19 vaccines were – when millions of people die every year from malaria. This is not to dispute the urgent global need for vaccines against Covid-19, but surely when a disease is so widespread and life-threatening as malaria is it demands the same urgency to tackle the endless death toll each year. Yet this is not the case, and one key reason why is the fact that it mainly affects lower-income, under-developed countries.

9There is presently only one vaccine against malaria and has the brand name Mosquirix. It requires four injections but even then, only offers approximately 30% protection against severe malaria, and only for up to four years. This raises arguments as to whether this vaccine is cost efficient. Additionally, there are further concerns over the safety of this vaccine; in a clinical trial for Mosquirix, the children who had received the vaccine had a risk of contracting meningitis that was 10 times higher than the children who had received the placebo. While there is not sufficient evidence to show that causation, this does hinder the potential safety of this vaccine and has, as a result, impeded rollouts of it. The new vaccine for malaria could gradually replace Mosquirix, and can mean that more individuals are protected against this disease.

Treatment:

Malaria is a curable disease and is treated using antimalarial drugs. The most common of these drugs is Chloroquine phosphate, but unfortunately this treatment is gradually being rendered ineffective due to increasing resistance of malarial parasites to it. Another type of antimalarial drug treatment is Artemisinin-based combination therapies (ACTs); ACT is actually a combination of antimalarial drugs and is used mostly where there is resistance to chloroquine phosphate. Primaquine phosphate is another frequently used antimalarial drug, in addition to quinine sulfate with doxycycline10. Noticeably, many antimalarial drugs contain the word ‘quine’ or ‘quinine’, as they often contain quinine, which is a chemical compound naturally derived from the bark of the cinchona tree.

Currently the Mayo Clinic is carrying out a clinical trial entitled “A Study to Evaluate Intravenous Artesunate to Treat Severe Malaria in the United States”11, and this study hopes to make intravenous artesunate available for treatment in cases of severe malaria. As of yet, there are no publications for this clinical trial.

The global management of malaria:

Currently there are global initiatives attempting to end the spread of malaria. One such example is the Mekong Malaria Elimination (MME) programme organised by the World Health Organisation (WHO)12. The MME programme is working towards eliminating malaria in Myanmar, Cambodia, the Lao People’s Democratic Republic, China, Vietnam, and Thailand, and began in 2017 in response to the increasing ineffectiveness of specific antimalarial drugs as a result of drug-resistant malarial parasites. On the 3rd of November 2020, Cambodia committed to completely eradicating P. falciparum by 202313. Dr Li Ailan, who is the WHO Representative to Cambodia stated: “. Cambodia, being very close to the goal, can be the first country in the region to eliminate P. falciparum malaria, serving as a champion in the Greater Mekong Subregion.” As part of this auspicious commitment, three main interventions have been set out: the distribution of mosquito screens and nets, malaria screening involving weekly fever screening for each household – and any individual with a fever will be tested for malaria and then receive treatment if they are positive for the disease, and furthermore, improved preventive measures for travellers to areas which are at-risk of the spread of malaria.

Conclusion:

Arguably malaria, as a disease alone, is theoretically relatively easy to prevent and treat: through insecticides, mosquito nets, vaccinations and antimalarials. In reality, the countries most affected by this disease do not have sufficient funds to provide this, let alone tackle the deep-rooted causes of poverty, poor access to clean drinking water and sanitation infrastructure, and malnutrition in addition to food insecurity – which collectively establishes an environment in which diseases, like malaria, can reach levels of epidemic. There needs to be a greater collective, global effort to tackle so-called ‘poverty-related diseases’ like malaria, but also cholera, typhoid and diphtheria to name more, as there was with smallpox and as there is now with Covid-19. That is not to discriminate against developed countries using their funds to further research healthcare and medicine in their own countries – as this is essential for advancing medicine and understandably they want to improve healthcare in their own countries first and foremost. Furthermore, it is also not to say that wealthier nations should extensively increase the amount of aid they give to ‘fix’ the healthcare problems in other nations – but, when aid is given, it should perhaps be directed to try and address the larger and more long-term socio-economic problems that allow diseases to manifest.

When aid is given in order to reduce the spread of malaria in the worst-impacted regions, it should simultaneously be used to improve the conditions which allow the disease to manifest and become so widespread. However, simply providing money to ‘fix’ these socio-economic problems is not a straightforward answer – as it ignores the presence of factors such as corruption, debt and prioritising immediate humanitarian aid over the longer-term social problems which are more difficult to fix due to their longevity and severity. Referring back to the ‘10/90 Gap’, this balance between the funding of disease mainly affecting the developed world and the ‘neglected diseases’ more prevalent in the developing world needs to be readdressed. When globally the disease burden is significantly greater in less developed regions, more aid needs to be directed towards this rather than disproportionately towards diseases that are less widespread and prevalent which impact more developed regions. 

There is no single, clear solution to the problem of malaria – and more broadly the ‘10/90 Gap’. However, it is undeniable that if malaria were as rampant across the developed world as it is presently in the developing world then there would undoubtedly be global upheaval to tackle this disease, and such a gap in funding would not be so significant. 

Samara Macrae, Youth Medical Journal 2021

References:

1.   Medscape: “What is the mortality rate of malaria?” – https://www.medscape.com/answers/221134-40790/what-is-the-mortality-rate-of-malaria

2.   Travel Health Pro: “Malaria” – https://travelhealthpro.org.uk/disease/113/malaria

3.   World Health Organisation: “Malaria Key Facts” – https://www.who.int/news-room/fact-sheets/detail/malaria

4.    Harvard TH Chan; School of Public Health: “Obesity Prevention Source” – https://www.hsph.harvard.edu/obesity-prevention-source/obesity-consequences/economic/

5.   Hill N, Lenglet A, Arnéz AM, Carneiro I. Plant based insect repellent and insecticide treated bed nets to protect against malaria in areas of early evening biting vectors: double blind randomised placebo controlled clinical trial in the Bolivian Amazon. BMJ. 2007;335(7628):1023.

6.   European Centre for Disease Prevention and Control: “Facts about malaria” – https://www.ecdc.europa.eu/en/malaria/facts

7.   NHS: “Antimalarials” – https://www.nhs.uk/conditions/malaria/treatment/

8.   TheScientist: “New Malaria Vaccine Shows Most Efficacy of Any to Date: Small Trial” – https://www.the-scientist.com/news-opinion/new-malaria-vaccine-shows-most-efficacy-of-any-to-date-small-trial-68710

9.   Sciencemag: “First malaria vaccine rolled out in Africa – despite limited efficacy and nagging safety concerns” – https://www.sciencemag.org/news/2019/11/first-malaria-vaccine-rolled-out-africa-despite-limited-efficacy-and-nagging-safety

10.   Mayo Clinic: “Malaria” – https://www.mayoclinic.org/diseases-conditions/malaria/diagnosis-treatment/drc-20351190

11.   Mayo Clinic: “A Study to Evaluate Intravenous Artesunate to Treat Severe Malaria in the United States” – https://www.mayo.edu/research/clinical-trials/cls-20502924

12.   World Health Organisation: “Mekong Malaria Elimination Programme” – https://www.who.int/initiatives/mekong-malaria-elimination-programme

13.   World Health Organisation: “Cambodia commits to eliminating Plasmodium falciparum malaria” – https://www.who.int/cambodia/news/detail/03-11-2020-cambodia-commits-to-eliminating-plasmodium-falciparum-malaria

Categories
Commentary

The present and future role of 3D printing in medicine

By Samara Macrae

Published 11:23 EST, Weds October 13th, 2021

Introduction:

3D printing, also known as additive manufacturing, is a process that holds enormous potential – and is not only currently used in medicine, but it will undoubtedly continue to revolutionise this field in the future. The process of 3D printing began in the 1980s, and this technology has been implemented into various areas of medicine – for example, medical imaging apparatus can often be fed into a 3D printer to form a physical model of the digital image. In 2016, the use of 3D printing in medicine was valued at $713.3 million, but this is predicted to rise to $3.5 billion by only 20251.  Within the field of medicine, 3D printing can additionally be used to produce implants as well as in bio-printing. Other major applications of 3D printing in medicine include producing artificial human organs for transplants and making surgical procedures faster and more efficient.

How does 3D printing work?

To begin with, before a physical 3D model can be created, a graphic model has to first be designed. This can be done using programs such as TinkerCAD and Fusion360. This digital model then needs to be ‘sliced’ in order for the printer to process the designs for the many layers – as it cannot fully conceptualize a 3D model in its entirety. This process is called ‘slicing’2. Once divided into layers, the design for each individual layer is fed into the printer, typically via a USB stick or can be done wirelessly. This is an example of an additive process, which is where a 3D object is created through placing many layers of material on top of one another. Each layer is a cross-section of the 3D object that has been created. 3D printing began as creating prototypes but has escalated into large-scale manufacturing due to how rapid the process is compared to other forms of industrial production.3 Manufacturing using a 3D printer can also be cheaper, as iterations are easier and there is no need for expensive tools nor high labour costs to manage the machines. 3D printing is utilized extensively in the car manufacturing industry, in order to produce individual vehicle parts on demand and en-masse. 3D printing is used in a multitude of other industries, including aviation and consumer products, such as eyewear and footwear.

Bioprinting and organ transplantation:

Bioprinting is a process similar to 3D printing, as it is an additive manufacturing process through which cells and other biomaterials are ‘printed’ to create biological structures in which living cells are able to divide and multiply4. The cells used to create complex bodily structures – such as skin, bones, and other organs – can be extracted directly from a patient. Adult stem cells can also be used, and they are cultivated into a bioink; this is a material used to produce artificial living tissue via 3D printing. Bioink can consist solely of the cells but can also contain a carrier material – typically a biopolymer gel. This will provide a 3D framework which the cells are able to attach to and spread out as they multiply5. The result of this scaffolding being in place means that the cells can be moulded into the desired shape. 

Bioprinting is a technique that is being researched currently, and Swansea University in the UK, has recently developed a bioprinting process6 by which bone matrix can be artificially produced using a regenerative biomaterial. This material is comprised of calcium phosphate, polycaprolactone, gelatine, agarose, and collagen alginate. This can potentially be used to correct severe and complex bone fractures, where otherwise the missing or damaged bones would be replaced with synthetic materials. This is part of the surgical procedure known as ‘bone grafting’. If the 3D-printed bone matrix is used instead, over time it will fuse with the patient’s bones and result in greater strength, compared to when synthetic materials would have been used instead.

In addition, the prospects of bioprinting extend further: for instance, the development of artificial corneas. Globally, there were approximately 12.7 million people in 2013 awaiting a corneal transplant, with 7 million of these individuals in India alone7. 8 In South Korea, in 2019, there were approximately 2000 people requiring a cornea donation – and the average wait time for surgery there is 6 years. This is due to the lack of cornea donations in the country as well as the problems associated with the current synthetic corneas available. These synthetic corneas are made from recombinant collagen or other chemical substances, like synthetic polymers, and one predominant problem with them is the fact that they are not always transparent after being implanted. This is due to the present inability to synthetically replicate the natural structure of the cornea being that of a lattice of collagen fibrils, which affects its transparency.

8However, a research team at the Pohang University of Science and Technology in South Korea, in conjunction with researchers at the Kyungpook National University School of Medicine also in South Korea, have worked to 3D print a cornea. This was done using a tissue-derived bioink, and this meant it is biocompatible with an individual’s eye. Bioprinting was utilised to create this artificial cornea in such a way that its transparency is akin to that of a natural human cornea. The joint research teams noticed, while working to develop a 3D printed cornea, that the collagen fibrils which were produced by the process of 3D bioprinting were similar to the lattice pattern found in human corneas.

9In other areas of bioprinting, the accomplishment of developing artificial organs suitable for transplantation remains a more futuristic hope. An example of this is a research project using 3D bioprinting of stem cells in order to create artificial, biocompatible kidney tissue. This research was led by the Murdoch Children’s Research Institute (MCRI) in Australia, alongside the American biotech company, Organovo. A 3D bioprinting process was used, in which a bioink created from stem cells was formed, and this produced an artificial kidney approximately the size of a human fingernail. Despite the small size, these bio-printed kidneys did contain very similar structures to human kidneys – including having nephrons and the division between the cortex and medulla being identifiable. While the research needs to continue to create artificial kidneys suitable for human transplantations, these kidneys are still functional for drug testing, predominantly for toxicity, instead of animal testing. Professor Melissa Little from the MCRI stated: “The pathway to renal replacement therapy using stem cell-derived kidney tissue will need a massive increase in the number of nephron structures present in the tissue to be transplanted.” This shows that the research is auspicious but requires considerably more time and effort.

The use of 3D printing in surgery:

3D printing is currently in use for many surgical procedures, and this will continue to increase as this technology develops. An example of this is using 3D printing to create patient-specific implants (PSIs) which are the exact complementary shape for the patient. For example, 10craniomaxillofacial reconstruction implants, which are used predominantly in head and neck surgery. These implants have to be bent into shape during surgery, which is time-consuming and is likely to place unnecessary stress on the implant as it has to be bent multiple times. In an article published in ScienceDirect entitled ‘A Systematic Approach for Making 3D-Printed Patient-Specific Implants for Craniomaxillofacial Reconstruction’10, the researchers discuss how they have devised an approach to this form of surgery, which has resulted in 41 successful surgeries using patient-specific implants which have been 3D-printed. This approach begins with using SolidWorks software to create a graphic design model to then print. The 3D-printed product undergoes a series of treatments – including heat and tension treatments – before being sterilised. The implant is then used in the surgery, and this article furthermore states that the use of these 3D-printed patient specific implants “reduces surgery time and shortens patient recovery time”.

A specific example of the use of 3D printing patient specific implants is a lower jaw implant, which was created for a child in China in 201811. This child had a mandibular tumour in his lower jaw which, if removed, would cause a severe facial malformation. However, this child needed to have this tumour removed as he struggled greatly with tasks such as talking, eating, and even opening his mouth. This led to him undergoing a surgery in which the tumour was removed, and the part of his lower jaw which was also removed was replaced using a titanium alloy implant. This implant had been 3D printed, using models of the child’s jaw, in order to create a patient-specific implant for him.

A further example is the use of a 3D printed patient-specific implant of an ossicle, in 2019. This implant was made, again, of titanium, and replaced the ossicles of the patient – as they had been damaged during a car accident and led to the patient losing their hearing. The medical team carrying this innovative surgical procedure was led by Professor Mashudu Tshifularo, a professor at the University of Pretoria in South Africa. As a result of this work, the patient’s hearing was restored11. This 3D-printed middle-ear replacement surgery was the first in the world, and according to the news platform ‘Good Things Guy’, Professor Mashudu Tshifularo said: “By replacing only the ossicles that aren’t functioning properly, the procedure carries significantly less risk that known prostheses and their associated surgical procedures”12.

Conclusion:

To conclude, while the technology of 3D printing in medicine can certainly progress in the future, it is still in use and being researched further currently. The promising nature of this process means that surgical procedures can continue to develop, becoming safer and more time-efficient, and there are the hopes of artificially creating biocompatible tissues and organs. This could revolutionise organ transplantation – not only reducing waiting times but additionally decreasing the risks of rejection. Furthermore, this technology could mean that implants are a better fit for the patient – as hip and knee replacements are some of the most common surgical procedures performed worldwide. The research for this technology is boundless and is one of many examples of computer technology merging with, and arguably, dominating the field of medicine in order to improve every aspect of it.

Samara Macrae Youth Medical Journal 2021

References:

  1. Medical Device Network: “3D printing in the medical field: four major applications revolutionising the industry” – https://www.medicaldevice-network.com/features/3d-printing-in-the-medical-field-applications/
  2. Interesting Engineering: “How Exactly Does 3D Printing Work?” – https://interestingengineering.com/how-exactly-does-3d-printing-work
  3. 3DPrinting.COM: “What is 3D Printing?” – https://3dprinting.com/what-is-3d-printing/
  4. Cellink: “Bioprinting Explained” – https://www.cellink.com/blog/bioprinting-explained-simply/#:~:text=Bioprinting%20is%20an%20additive%20manufacturing,that%20let%20living%20cells%20multiply.
  5. All3DP: “What Exactly is Bioink?” – https://all3dp.com/2/for-ricardo-what-is-bioink-simply-explained/#:~:text=Bioink%20is%20the%20material%20used,as%20a%203D%20molecular%20scaffold.
  6. Medical device Network: “The future of bioprinting: A new frontier in regenerative healthcare” – https://www.medicaldevice-network.com/features/future-of-3d-bioprinting/?utm_source=Army%20Technology&utm_medium=website&utm_campaign=Must%20Read&utm_content=Headline
  7. JAMA Network: “Global Survey of Corneal Transplantation and Eye Banking – https://jamanetwork.com/journals/jamaophthalmology/fullarticle/2474372
  8. Medical Device Network: “3D-printed artificial corneas could replace donor transplants” – https://www.medicaldevice-network.com/news/3d-printed-corneas/
  9. XINHUANET: “Aussie research on bioprinting mini kidney raises hope for lab-grown transplantation – http://www.xinhuanet.com/english/2020-11/24/c_139540203.htm
  10. ScienceDirect: “A Systematic Approach for Making 3D-Printed Patient-Specific Implants for Craniomaxillofacial Reconstruction” – https://www.sciencedirect.com/science/article/pii/S2095809920302794#:~:text=Patient%2Dspecific%20craniomaxillofacial%20reconstruction%20implants%20are%20made%20using%20a%20selective,quality%2Dcontrol%20procedure%20is%20needed.
  11. 3Dnatives: “Top 12 3D Printed Implants” – https://www.3dnatives.com/en/best-3d-printed-implants-230720195/#!
  12. AFROTECH: “Mashudu Tshifularo Makes History By Performing World’s First 3D-Printed Middle-Ear Transplant” – https://afrotech.com/mashudu-tshifularo-makes-history-by-performing-worlds-first-3d-printed-middle-ear-transplant
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The Complexities of Colour Blindness and its Impacts on Individuals

By Samara Macrae

Published 12:33 PM EST, Tue August 17, 2021

Introduction

While commonly referred to using the term ‘colour blindness’, colour deficiency vision instead is the term used when an individual’s colour vision is impaired, and as such they may not be able to distinguish between different colours1. Colour blindness is only where the individual cannot see any form of colour, and their vision is exclusively in black and white (monochromacy). This condition is very rare, while colour deficiency vision (a form of colour blindness) can affect up to 1 in 12 men and 1 in 20 women. The most common forms of colour blindness are protanopia and deuteranopia.

2Monochromacy, or complete colour blindness, can be caused by the individual having two sets of cones (out of short wave, medium wave, and long wave) which either do not function correctly or are simply not present in the retina. This results in the individual not being able to see a full spectrum of colour as a person with normal vision (which is also known as trichromatic vision) would be able to. Achromatopsia is where there are no functional cone cells at all, and so vision is only in varying shades of black and white.

Variations of Colour Deficiency Vision

3Red-green colour blindness is the most common form of colour blindness and is divided into two types: protan colour blindness is reduced sensitivity to red light, and deuteranopia is sensitivity to green light. Colour vision is controlled by cones in the retina, a layer of the eye onto which light is focused on, and when some of these cones are ineffective or not present, this will affect the individual’s colour vision. Protanopia is the result of missing long-wavelength cones (L-cones) in the retina and affects 1.01% of men but only 0.02% of women. People with protanopia as a result of missing L-cones are ‘dichromats’, and they have cones which can only detect short and medium wavelengths. Red-green colour blindness can also occur due to L-cones being defective but still present (protanomaly) and means that individuals can have varying strengths of colour blindness – this is referred to as anomalous trichromats, as the individual can still detect short, medium, and long wavelengths using their cones. 4Deuteranopia is the second form of red-green colour blindness and is also called green-blind. In cases of deuteranopia, the medium wavelength sensitive cones are missing – and so the individual can only differentiate between 2 or 3 different shades (typically blue, yellow, and brown), while a person with normal vision can distinguish between the 7 hues of visible light. As with deuteranopia the specific cones are missing, people with this condition are dichromats. Anomalous trichromats are individuals with deuteranomaly (green-weak), which is where the green-sensitive cones are deficient. Deuteranomaly can be very mild and is any form of colour deficiency vision between (very close to) normal vision and deuteranopia. Deuteranomaly affects 5% of the global male population, but only 0.35% of the global female population. 5Tritanopia (blue-yellow colour blindness) is where the short-wavelength cones are missing or otherwise impaired. Tritanopia is where these cones are completely missing, and only long and medium-wavelength cones are in the retina – and individuals with tritanopia are dichromats. Tritanomaly is where the short-wavelength cones are deficient in some way, often due to a mutation.

Inheritance

Colour blindness is a sex-linked genetic disorder and is carried on the X-sex chromosome. This is why men are more likely to have colour blindness, as they only have one X-sex chromosome and so only require one recessive allele coding for colour blindness. Women have two X-sex chromosomes though, and so two recessive alleles are needed for colour blindness – meaning that if a woman only has the allele for colour blindness on only one X chromosome, she will be a carrier but not have the condition herself. As a result, a man with colour blindness can pass this condition onto his daughter, who will inherit an X-sex chromosome from him as well as the mother but cannot pass the condition onto his son – who will inherit an unaffected Y-sex chromosome from him. Unlike both protanopia and deuteranopia, tritanopia/tritanomaly is not a sex-linked genetic trait – and thus men and women are affected equally by it, though it is a rare form of colour deficient vision – as it is carried on the 7th chromosome instead of the 23rd (the X-sex chromosome). Additionally, though less commonly, colour blindness or colour deficiency vision can also be the result of damage to the eye or optic nerve – as so is not necessarily solely congenital.

Diagnosis

While people who have colour blindness/colour deficient vision may not ever realise they have the condition, tests to ascertain whether a person is colour blind are often widely accessible. An example of such a test is the Ishihara Test for Colour Blindness. This diagnostic test was created by Dr Shinobu Ishihara, an ophthalmologist, as he was asked by the Japanese Army (in which he served as a military doctor) to devise such a test to use on those conscripted for the Army. The Ishihara Test can be used to detect red-green colour blindness/deficiencies but not the rarer form of yellow-blue colour blindness6. As part of this test, an individual is shown a series of coloured circles consisting of multiple small circles to make up a larger one. Within this larger circle, some of the smaller circles are differently coloured to make the shape of a specific number (which is different for each image). Depending on whether or not a person is able to ascertain what the number is within each image can help to indicate whether or not they have normal vision or colour deficiency vision.

Correction

Colour blindness is incurable, although some forms of colour deficiency can be lessened using corrective lenses or glasses. 7Dr Ivan Schwab, Professor of Ophthalmology at the University of California, says that such glasses or lenses “[enhance] the distinction between red and green” for the person wearing them, although full colour vision is not achievable using them. He also states: “Colour blindness glasses are made with certain minerals to absorb and filter out some of the wavelengths between green and red that could confuse the brain”. This can result in fewer colours being detected by the person’s cones, and so can allow for easier distinction between them. However, these corrective lenses or glasses do not have any effect on the optic nerve, brain, or cone cells – and furthermore, these lenses/glasses are often expensive yet yield minimal to no results, and additionally can worsen vision at night due to the fact that they work by reducing the amount of light entering the eyes and being detected.

Difficulties and Lack of Accessibility

Although many individuals with colour blindness or colour deficiency vision, as well as charities such as Colour-Blind Awareness, are campaigning for these conditions to be classified as disabilities, they are not currently. Under the 2010 Equality Act (UK), a disability is defined as “a physical or mental impairment that has a ‘substantial’ and ‘long-term’ negative effect on your ability to do normal daily activities”8. A simple but common example of how colour blindness can affect activities of everyday life is a person with deficient colour vision not being able to differentiate between unripe and ripe fruit, or raw and cooked meat. In addition, children especially can struggle in education as a result of their colour deficiency vision – and exam papers especially may not be fully accessible to them – and later in life, a person with colour blindness cannot become a pilot nor enter the army. Colour vision deficiency can also limit other future career options – particularly jobs involving heavy machinery, a job in aviation or any job predominantly based around driving. The consequences of colour blindness can also be potentially fatal – such as problems with traffic lights leading to road accidents. A person with protanopia may not be able to distinguish between the red and green traffic lights – for a person with protanopia, the lights can all look white/pale yellow – and so is potentially more likely to be involved in road accidents as a result. In Australia, since 1994 individuals with either protanopia or protanomaly have not been able to obtain a driving licence due to the increased risk of accidents.

Conclusion

To conclude, colour blindness is a complex condition which can be frequently misunderstood due to the multiple variations of the condition. Furthermore, there are frequent misconceptions as to what ‘colour blindness’ actually entails – as it is not any form of difficulty to distinguish between colours, but rather no colour vision at all. Education systems should work to help diagnose more children who have colour deficiency vision or colour blindness, as it can impede their daily life and schoolwork if they are unaware of their condition – and thus education facilities are unable to make education/work more accessible to them without this knowledge. Improved testing and diagnosis earlier on – especially for children in early years – can additionally mean that they do not suddenly find themselves unable to pursue a specific career path or obtain a driving licence when they are older, as they were not aware of their colour deficiency vision/colour blindness beforehand. While not life-threatening, colour blindness and colour deficiency vision can have significant impacts on daily life, and simply diagnosing these conditions earlier can help improve accessibility for all aspects of life for these individuals.

Samara Macrae, Youth Medical Journal 2021

References:

1.   Mayo Clinic: “Colour Blindness” –  https://www.mayoclinic.org/diseases-conditions/poor-color-vision/symptoms-causes/syc-20354988

2.   Cambridge Cognition: “Could Colour Blindness be Affecting the Results of your Study?” – https://www.cambridgecognition.com/blog/entry/could-colour-blindness-be-affecting-the-results-of-your-study#_cc-image3

3.   Colblindor: “Protanopia” – https://www.color-blindness.com/protanopia-red-green-color-blindness/

4.   Colblindor: “Deuteranopia” – https://www.color-blindness.com/deuteranopia-red-green-color-blindness/

5.   Colblindor: “Tritanopia” – https://www.color-blindness.com/tritanopia-blue-yellow-color-blindness/

6.   Eye Magazine: “Nine decades on, a Japanese army doctor’s invention is still being used to test colour vision” – http://www.eyemagazine.com/feature/article/ishihara

7.   American Academy of Ophthalmology: “Do Colorblindness Glasses Really Work?” – https://www.aao.org/eye-health/tips-prevention/do-color-blindness-correcting-glasses-work

8.   GOV.UK: “Definition of disability under the Equality Act 2010” – https://www.gov.uk/definition-of-disability-under-equality-act-2010