Saturday, February 22, 2020

Demonstrating brain abnormalities in major mental illness

Following up my last post about Lindsey Sinclair's BJPsych Bulletin commentary, I want to comment on how she insufficiently considers non-specific other explanations (including medication) for the so-called brain abnormalities which she thinks have been demonstrated in major mental illnesses. As she says, the modern resurgence of biomedical psychiatry goes back to a 1976 paper by Eve Johnstone, Tim Crow et al showing cerebral ventricular enlargement in chronic schizophrenia (see previous post). Brain tissue volumes decrease and CSF volumes increase over time may also be due to medication or non-specific factors (see another previous post). Sinclair admits that it has been difficult to prove definitively whether there are differences in volume even before the at-risk mental state (see another previous post).

I just think this evidence demands more cautious assessment. Why doesn't she mention that brain scanning studies are plagued by inconsistencies and confounders? (see yet another previous post). Certainly Sinclair cannot conclude that the null hypothesis has been rejected and that biological abnormalities have been demonstrated in major mental illnesses. In fact, it's more scientific to say they haven't been demonstrated. Sinclair does accept that "neuroscience is unlikely to hold all of the answers to why people develop mental disorders and when they occur in their lifetime". She needs to consider this issue further.

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