Bipolar: Nature or Nurture?

by R. M.
(Huntington, NY, USA)

Bipolar: Nature or Nurture?

It has only been relatively recently conceptions of mental illness have come out of the dark ages. With no known scientific cause for centuries, barbaric treatments such as bloodletting and casting out of demons, mixed religious ideology and mythology with medicine to provide an explanation for the unexplainable. Following proponents of psychological triggers like Freud, and inhumane procedures like lobotomy, the advent of modern medicine in the latter part of the 20th century ushered in, however, the development of- psychotropic medication which proved widely successful and changed the way mental illness is viewed and treated.

When you hear the term bipolar these days very often the term chemical imbalance is also mentioned. After countless research studies, the medical community has concluded that it is not just environmental triggers but specifically a biological defect in the brain that causes the cluster of symptoms known as bipolar: imbalances in the important chemicals dopamine and serotonin. In effect, a nature over nurture approach.

Very often bipolar is compared to diabetes or other medical illnesses; however, there really has been no solid proof that a defect in the brain of a bipolar patient absolutely exists as with other physiological disorders and that it is inextricably linked to mood swings and other symptoms of the illness. There are no blood test or imaging procedures that can identify bipolar a brain disorder. Some scientists have found differences in the size of cerebellum in bipolar patients, in the metabolism of brain chemicals as well as decreases activity in part of the brain of depressed patients.

While this science-based approach has resulted in successful treatment, it is important to also take into account alternative explanations when drawing conclusions on causes of mental illness like bipolar and schizophrenia.

Well then how do we explain the efficacy of psychotropic medications in the management of this disorder? The fact is that pharmaceutical companies that manufacture these drugs cannot explain how they work. According to naturopathic doctor Tara Peyman, these drugs help by creating another mental state by altering the chemistry in the brain, not necessarily correcting one that exists.

This enigma has perplexed the science and medical community for years. That is, if bipolar is a biological chemical imbalance could it be possible that any emotional disturbance actually causes the imbalance and not the other way around? All emotions cause biological changes in the brain. Changes have been shown in brains of people who are sad and blue but have no diagnosis of mental illness.

Some believe that it is a combination of hereditary biological predisposition and environmental psychological factors which lead to bipolar onset. However, once again there exists no absolute empirical evidence, such as a genetic marker or physical abnormality to support this.

Two genes have been identified in playing a role in bipolar disorder in a study showing a clear idea of the chemicals and mechanisms in the brain involved in bipolar, but again, it doesn?t offer a direct link. Also, PET scans have shown differences in the brains of bipolar patients. However, changes have also been seen in the brains of advanced mediators, thus differences do not ncessarily indicate organic or physiological abnormalities.

Other theories proposing that early childhood trauma is connected to onset of bipolar challenge the widespread belief that severe mental illness is not a reaction to extremely disturbing circumstances and merely biologically based, and that dysfunctional thought patterns are no more than neurologically malfunctions in thinking. Part of this theory claims psychotic and hallucinations components of bipolar (and schizophrenia) are actually dissociative symptoms, as in post-traumatic stress disorder.

A significant amount of research has pointed to this correlation. It has been theorized that physical aspects of psychotic illness seen in bipolar could be an emotional and behavioral response to early stressors. Some studies actually link high levels of stress and manic-depressive illness. Another interesting theory sees the illness as a defense mechanism for dealing with severe stressors. For example, manic episodes being an escape route from the reality of negative events. Also, the destabilizing effects that stressful events have on biological rhythms has also been hypothesized a cause.

Stress in general has been linked to onset of a depressive episode. Negative thought patterns resulting from trauma, particularly feelings of dejectedness, pessimistic predictions about the self, world and future. Temperament patterns with emotional reactivity, are also implicated in the biological underpinnings of personalities that develop behavioral abnormalities. In seeking to explain schizophrenia, a group of researchers studied links between some adults with psychotic symptoms that had underlying vulnerability and high sensitivity and response to stress. Usually these traits are considered symptoms, but are they believed to be, in fact, part of effects of the abnormal neurodevelopment process that evolves during childhood trauma. For example, studies have shown repeated stress and childhood trauma have effects on the hippocampus, amygdale and medial prefrontal cortex atrophy and dysfunction that mediate anxiety and mood problems. Also, childhood trauma has been shown to cause defects in dopamine metabolism.

Despite all the research on both ends of the biological-psychosocial spectrum, it is likely the causes of bipolar disorder will remain controversial for quite some time. Being aware of all the different possibilities can help someone with the disorder better understand him or herself and find the best treatment to meet their needs.