It’s often claimed that mental illnesses derivate from a ‘’chemical imbalance’’ on the brain –that occurs when there’s either too much or too little of certain chemicals, called neurotransmitters- but that would be diminishing how complex those disorders are. In fact, APA (American Psychiatric Association) defended in 2005 that ‘’the exact causes of mental disorders are unknown’’. In that same year, Drs Thomas Insel and Remi Quirion proposed that mental disorders need to be ‘’addressed as disorders of distributed brain systems with symptoms forged by developmental and social experiences.”
Pies, RW. (2014, April) Nuances, Narratives, and the ‘’Chemical Imbalance’’ Debate [Blog Post.] Retrieved from https://www.psychiatrictimes.com/view/nuances-narratives-and-chemical-imbalance-debate (last accessed on 13th October 2020)
Mental illnesses don’t simply result from an amount of certain brain chemicals, but of a set of probable causes, such ‘’as faulty mood regulation by the brain; genetic vulnerability; stressful life events such as a history of physical, psychological, or emotional abuse; medications; medical problems genetics; family history; having a history of alcohol or illicit drug use and taking certain medications psychosocial factors, such as external circumstances that lead to feelings of isolation and loneliness’’.
Harvard University. (2009, June) What causes depression? Harvard Health Publishing Retrieved from https://www.health.harvard.edu/mind-and-mood/what-causes-depression; Eske, J. (2019, September) Everything you need to know about chemical imbalances in the brain, Medical News Today Retrieved from https://www.medicalnewstoday.com/articles/326475#myths (last accessed on 13th October 2020)
However, chemicals are involved, it’s just not as simple as ‘’one chemical being too low and another too high”, but of millions and billions of chemical reactions working both inside and outside of nerve cells. There are specific areas of the brain that regulate it so scientists believe that the cause of these disorders might lie in the nerve cell connections, nerve cell growth and functioning of nerve circuits rather than on levels of brain chemicals. The use of antidepressants supports this theory because despite the immediate increase of chemical messengers on the brain, the patients take several weeks or longer to feel results. The researchers started to question why; if depression was only the result of low levels of neurotransmitters, how come people didn’t feel better as soon as their number is increased? They then progressed their theory to ‘’the real value of these medications may be in generating new neurons (a process called neurogenesis), strengthening nerve cell connections, and improving the exchange of information between nerve circuits. If that's the case, depression medications could be developed that specifically promote neurogenesis, with the hope that patients would see quicker results than with current treatments.’’ However, the understanding of the neurological function influence in disorders is incomplete and therefore, susceptible to change.
Burns, D.D. (2017, December). Do depression and anxiety result from a Chemical Imbalance in the brain? [Blog Post]. Retrieved from https://feelinggood.com/2017/12/12/do-depression-and-anxiety-result-from-a-chemical-imbalance-in-the-brain/ (last accessed on 13th October 2020)
Professor David D. Burns, a winner of A. E. Bennett Award from the Society for Biological Psychiatry, among others, dedicated a long time of his life studying the chemical imbalance theory but stopped when he ‘’realized that the chemical imbalance theory was not a productive or valid.’’ In one of his clinical studies, he flooded the brains of depressed veterans with serotonin – a neurotransmitter that was believed to cause depression when in deficiency- but there was no effect on their moods or disease. This led him to believe that the theory wasn’t accurate and he now defends that although there are biological brain disorders, he finds unlikely that mental disorders are a ‘’chemical imbalance’’ since the brain itself it’s not a ‘hydraulic system of balances and imbalances.’’. Instead, he thinks that ‘’Everything about being human results from biological (genetic) and environmental influences—such as IQ, personality, height, hair colour, and the proclivity to being naturally more negative in outlook (depression, anxiety, shyness, anger) or more naturally positive (happy, confident, outgoing). However, we do not yet have much understanding of the brain systems that are involved. To what extent is depression the result of problems with our hardware (tissue level brain abnormalities or damage) vs. software (learning, neural circuitry, etc.)? We just don’t know.’’
Burns, D.D. (2017, December). Do depression and anxiety result from a Chemical Imbalance in the brain? [Blog Post]. Retrieved from https://feelinggood.com/2017/12/12/do-depression-and-anxiety-result-from-a-chemical-imbalance-in-the-brain/ (last accessed on 13th October 2020)
Depression
Dissociative Disorders
A dissociative disorder is a mental disorder that involves dissociation, phenomenon described by the Sidran Institute as "a disconnection between a person’s thoughts, memories, feelings, actions, or sense of who he or she is". A mild example of this experience is daydreaming or any experience that allows one to "lose touch" of one’s immediate surroundings.
Sidran Institute. What is a dissociative disorder?. (2018, November). Retrieved from https://www.sidran.org/wp-content/uploads/2018/11/What-is-a-dissociative-disorder.pdf (last accessed on 09-10-2020)
A dissociative disorder happens in consequence of repeated and intense trauma, mostly physical, sexual, and/or emotional abuse during childhood (usually before age 9), when the child feels helpless and without an escape, although victims of natural disasters, invasive medical procedures, war, kidnapping and torture may also develop it, as a coping mechanism. People may also inherit a biological predisposition for this disorder, but it's very rare for it to develop without having experienced heavy trauma.
Dissociation creates amnesic walls that can keep the person from remembering the details of the event, in order to help deal with the trauma that would otherwise be too difficult to bear. This experience may help when one is feeling unsafe, uncomfortable or overwhelmed, since it provides a mental escape from the fear, pain, and horror. However, this also has disadvantages when the person dissociates too often, creating issues in relationships and trouble functioning.
Women are more likely to be diagnosed with one of these disorders, but they are equally prevalent (but less frequently diagnosed) among men. This happens because men are more likely to deny symptoms and be mis-diagnosed as having an attention deficit disorder (mainly among children), bipolar disorder, schizophrenia, psychoses and addictions.
Symptoms
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Significant memory loss of regular occasions, personal information and/or traumatic experiences;
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A sense of separation from your feelings and yourself, or emotional numbness;
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Distorted, blurred and unreal sense of the reality around you and your own identity;
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Mental health issues, namely anxiety, depression and suicidal thoughts and behaviours;
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Sleep disorders, panic attacks and eating disorders.
Diagnosis
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Physical test - Examination by a doctor, answering a survey, analysing the symptoms and personal history, in order to rule out physical causes;
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Psychiatric test - Discussion with a mental health professional about symptoms, behaviour, thoughts and feelings.
Types of Dissociative Disorders
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Dissociative Identity Disorder (DID)
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Dissociative Amnesia
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Depersonalization-derealization disorder
Dissociative Identity Disorder (DID):
Formerly known as Multiple Personality Disorder, this mental illness is the most extreme manifestation of a dissociative disorder and can only be developed has a direct consequence of intense trauma during childhood, since at this point the personality is not fully integrated yet.
A person with this disorder has a fragmented personality and experiences themselves as having separate identities or alters. These may present different age, gender, functions or roles, preferences, attitudes, memories and perception of their appearance. While these alternate states may feel or appear vastly different, they are all manifestations of a single, whole person
DID has been confirmed to affect 1% of the general population, putting it in the same group as depression, anxiety and schizophrenia as the four major mental health issues currently. This percentage increases among sexual-abuse survivors, addicts and people in psychiatric hospitals.
The main symptom that differentiate DID from other dissociative disorders is the presence of two or more states of consciousness (or "alters"). These go along with changes in behaviour, memory and thinking.
Dissociative Identity Disorder probably has the best prognosis compared to other severe psychiatric disorders in terms of being cured if provided correct treatment. It responds very well to psychotherapy, medication and other types of long-term and intense therapy and treatments. In the end, after remembering and reclaiming the traumatic experiences the different states of consciousness can merge into a one whole "personality".
Dissociative Amnesia:
The main symptom is the inability to remember important information about yourself, people in your life and/or personal experiences and events, usually traumatic.
Amnesia episodes occur unexpectedly and may last as short as minutes or as long as years. In rare instances, the amnesia can cause a phenomenon called dissociative fugue, in which people disappear from their usual environments, leaving their family and job, wandering away from their life.
The amnesia can be localized, selective, generalized, systematized or continuous.
Most patients are not aware of the loss of memory until personal identity is lost.
The treatment to this disorder is usually psychotherapy, which can be combined with medication and hypnoses and if the person is in a safe environment they are very likely to recover their missing memories.
Depersonalization-derealization disorder:
This disorder involves the on-going or episodic experience of depersonalization and/or derealization. Depersonalization consists in the belief that you yourself are unreal as well as feeling detached from your body or mental process, while derealization is the detachment from your surroundings.
These two phenomena can be symptoms of other illnesses, however when they occur without any other mental or physical disorder, persistently and recurrently, undermining the person's function we are in the presence of a depersonalization-derealization disorder.
This disorder is triggered by severe stress and it's equally prevalent in men and women, developed usually during the childhood.
The treatment for this disorder is psychotherapy, even though some patients recover without intervention.
Neurobiological View of Dissociative Disorders:
The neurologic causes of dissociative disorders and how child trauma affect the brain are still unknown, however there have been a few studies with the goal of understanding this illness, mostly recurring to neuroimaging, a recent area of study of the brain’s anatomy and function, fundamental to the understanding of neurobiology. As a result, there are some limitations in these studies, like only including female patients, therefore it’s important to keep in mind that the study of the neurological causes of dissociative disorders is still in its infancy.
Studies have shown that patients with a history of childhood abuse often present a smaller hippocampal volume, which is responsible for forming long-term memories, learning and stress regulation, which made scientists believe this might be the key to understanding dissociative identity disorder (DID).
Vermetten, et al. performed a study that compared the brain structure of female patients with DID to healthy subjects and observed that the patients with the disorder possess smaller sized hippocampus and amygdala, that is responsible for regulating emotions, supporting the theory that these components of the brain are the cause of the disorder. Sadly this study was discredited by another that compared the same brain structures in patients with post-traumatic stress disorder (PTSD) to healthy subjects and to subjects with dissociative amnesia (DA) or DID but not PTSD, concluding that the smaller hippocampus and amygdala were related with the PTSD and not the dissociative disorder. Vermetten has confirmed this possibility since all the patients with dissociative disorders in their study also displayed symptoms of PTSD.
The orbitofrontal cortex (OFC), responsible for decision making, the emotional processing of sensory information and self-regulation (that is associated to the concept of a unified personality), has also been the subject of two studies as one of the possible causes of DID, in which was measured the regional cerebral blood flow (rCBF), that represents the relative activity of different parts of the brain. In the first it was compared the rCBF of DID subjects to healthy subjects, observing lower rCBF in the OFC of DID patients. This led them to hypothesize that the lower functioning of the orbitofrontal cortex provokes impulsivity and that the switch to an alternative identity is caused by an extreme expression of impulsive behavior induced by cognitive and emotional conflicts. The second study, performed by Reinders, et al., consisted in the listening of two autobiographical audiotaped memory scripts, one associated with a neutral experience and another with a traumatic experience, by DID subjects in a neutral personality state (NPS) and in a traumatic personality state (TPS). No difference was observed when the NPS and TPS listened to the neutral script, neither between the neutral and the traumatic script for the NPS. However, it was discovered a deactivation pattern of brain areas in NPS while listening to the traumatic script, which matches the deactivation pattern observed in studies of healthy subjects when hearing non-autobiographical memories compared to autobiographical ones. This brought them to the conclusion that the alters have different autobiographical selves. It was also observed the deactivation of the prefrontal cortex, that contains the OFC and is associated with personality expression, among other parts of the brain. Both of these studies demonstrate the importance the orbitofrontal cortex has in the understanding of DID.
As it was already discussed, most of the scientific community agrees that the main cause of DID is intense childhood trauma. This can cause a child to develop disorganize attachment towards the caregiver, experiencing conflict since they need the caregiver for safety but, at the same time, they feel the need to protect themselves from them. This can cause the child to develop various states of self, using dissociation to help handle stress and traumatic experiences. Studies have also shown that, even though the disorganize attachment is most likely caused by poor parenting and maltreatment, there’s also a genetic risk factor, since children with a specific gene (DRD4) are four times more likely to display disorganize attachment and, therefore, developing DID.
There have been other less known studies that try to prove the neurobiological cause of dissociative disorders, that tested different parts of the brain. The parietal cortex, responsible for the integration of somatosensory information, has been linked to depersonalization and dissociative symptoms (Chalavi et al., 2015 and Siegel & Sapru, 2015); increased dissociative states have been associated with a larger postcentral gyrus, a sensory receptive area of the parietal lobe (Irle et al., 2007); larger putamen and pallidum have been observed in DID patients and in patients with DID-PTSD compared to PTSD patients; these have also been connected with the extension of the depersonalization and dissociative symptoms (Reinders et al., 2019 and Chalavi et al., 2015).
As we can see, there are a lot of theories as to what causes DID and other dissociative disorders. At this point in time specialists still have not come to a consensus, but these studies make up a good basis for the work of future researchers.