Rethinking How We Diagnose Psychosis

Posted on December 16, 2015

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If you are unfortunate enough to develop acute chest pain this winter you will probably be assessed by a clinician who will order a battery of tests to determine if your symptoms result from pneumonia, bronchitis, heart disease, or something else. These tests not only can yield a precise diagnosis, they ensure you will receive the appropriate treatment for your specific illness.

If you are unfortunate enough to have a psychotic episode this winter, the process of arriving at a diagnosis will be quite different. In fact, there are not many choices. Most people with a psychotic disorder are labeled as having either schizophrenia or bipolar disorder. The distinction has been in textbooks for a century: schizophrenia is associated with delusions, hallucinations, an absence of affect, and a chronic course; bipolar can also involve delusions and hallucinations, and typically, dramatic swings in mood and a fluctuating course. But outside of textbooks, in the real world of the emergency room or clinic, these distinctions are less clear as many patients do not neatly fit the formal descriptions. Sadly, there are no blood tests or scans to distinguish schizophrenia from bipolar disorder.

While clinicians have become very skilled at assessing symptoms and signs, the absence of diagnostic laboratory tools or biomarkers poses a serious problem in psychiatry. Do all people with a label of schizophrenia have the same disorder? What about the large number of people who appear to have aspects of both schizophrenia and bipolar? Are these disorders, diagnosed exclusively by signs and symptoms, identifying distinct biological entities or could there be many different illnesses with a continuum of psychotic signs and symptoms? These questions are not merely academic. As with chest pain, getting a precise diagnosis is important for selecting the best treatment.

Moving psychiatry into a new era of biologically based diagnosis has been a long sought goal. Now, a new study published in the American Journal of Psychiatry raises fresh hope. 711 people with a diagnosis of schizophrenia, bipolar disorder, or schizo-affective disorder (a hybrid of schizophrenia and bipolar disorder) were assessed with a brain-based panel of cognitive tests, studies of eye movements, a test of cognitive control, and electro-encephalogram. In addition, each subject had a brain imaging scan.

The study found distinct “biotypes” of psychosis that can be identified with quantitative biomarkers. Ignoring the clinical diagnosis, researchers pooled the data and analyzed it with unbiased, criterion-free statistical methods to look for what they called biotypes. Not only did the three biotypes have very little relationship to the three diagnostic categories, people with schizophrenia and bipolar and schizo-affective disorders were distributed across the three biotypes. The biotypes also did not differ simply by symptom severity or the presence of mania-related symptoms.

The current article has been adapted in content for length. Follow the link below to read it in full.


Category(s):Mental Health Professions

Source material from Scientific American


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