Ditching our simplistic systems for categorising mental health problemsBMJ 2016; 352 doi: https://doi.org/10.1136/bmj.i1044 (Published 23 February 2016) Cite this as: BMJ 2016;352:i1044
Van Os is correct that the various categories of “psychotic” illness we find in ICD-10 (international classification of diseases, 10th revision) do not represent discrete diseases but rather describe clusters of symptoms or overlapping syndromes.1
He is also right that there is little evidence to distinguish schizophrenia (as defined in ICD-10) from the other functional psychoses, either by cause or prognosis (despite the unfortunate assertion he describes in DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, fifth edition)) and that the biologist’s preoccupation with the cause of “schizophrenia” may have undermined our understanding of the causes of most serious mental illnesses.
However, he fails to consider that the term “psychosis” is as problematic and misleading as the category schizophrenia. A Google search of this term brings up myriad descriptions of the cardinal features of this supposed condition. Some emphasise “impaired reality testing,” others describe an impaired ability to “perceive or interpret,” while others emphasise “a radical change or disorganisation in personality.”
An examination of ICD-10 or DSM shows that some people with “personality disorders” have a radical change or disorganisation in personality, some with “eating disorders” have seriously impaired reality testing, and some with serious “depression” have impaired ability to perceive or interpret.
Just as schizophrenia cannot be properly distinguished from other psychoses, psychosis cannot be properly distinguished from other mental disorders. In my opinion the “diagnostic paradigm,” so loved by most British psychiatrists (and American drug companies), is the problem here. We need a more radical approach. We should ditch our simplistic categorical systems and focus on historical narrative; objective symptom measurement; and considered formulation of cause, prognosis, risk, and capacity. Adolf Meyer, often regarded as the father of modern psychiatry, described this approach almost 100 years ago. Pity we didn’t listen.
Competing interests: None declared.