Wednesday, May 17, 2023

Barriers to debunking the serotonin theory of depression.

I concluded my article on 'Towards a more relational psychiatry: A critical reflection' with the sentence:-

Rather than psychiatric practice being based on the notion that primary mental illness will be found to have a physical cause, psychiatry needs to move on to a more relational practice.

I just want to elaborate what I mean by this in relation to the umbrella review that confirmed there is no convincing evidence to support the theory that depression is caused by low serotonin (see previous post). Even though antidepressants may be serotonin re-uptake inhibitors, they do not seem to correct an imbalance or deficiency of serotonin in the brain (see another previous post). 

This may well be surprising to patients and the general public who have been led to believe in the serotonin theory of depression. Simplistic notions of the serotonin theory have actually been untenable for some time (see eg. previous post). Psychopharmacologists gave up the theory ages ago but it persists in clinical practice as a way of persuading patients to take their medication. I'm sure the fundamental faith of psychiatry that primary mental illness will be found to be due to brain disease will continue. Doctors find it difficult to accept that depression hasn't something to do with serotonin because antidepressants can be serotonin re-uptake inhibitors. They are convinced antidepressants work, so this must be due to their effect on serotonin. 

Our modern understanding of illness and disease as bodily pathology has been remarkably successful in elucidating biological processes of disease. Doctors should take a person-centred approach to attain an understanding of the patient as well as the disease. For psychiatry in particular, the danger is that medicine may treat patients more as objects than people by reducing their problems to brain disease.

After decades of intense neuroimaging research, there is still no neurobiological account of any functional psychiatric condition (see eg. previous post). Psychiatry must stop identifying the brain with the person. People’s experience and relationships with others are at the core of depression and cannot be identified with neuronal or biochemical processes, such as serotonin imbalance or deficiency. We may find it attractive to try and simplify the relationship between mind and brain, but it may well be an enigma we cannot solve. We have to accept the integration of mind and brain in the person. Of course brain disease can cause mental disorder, but it may well not make sense to see depression as being in the brain. Depression is mediated by the brain but there may be no brain abnormality as such. This is what psychiatry will continue to find difficult to accept.

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