This issue of Psychiatric Annals continues with more articles examining the similarities and differences between the diagnostic categories of schizophrenia versus psychotic bipolar disorder, or between the psychotic mood disorders and schizophrenia. Guest editor C. Ray Lake, MD, PhD, has again delivered a series of articles by highly respected clinician-research investigators, as well as an article describing his own take.
Does the available evidence justify reclassifying patients diagnosed with schizophrenia as having a psychotic mood disorder? Reading last month’s articles, along with this month’s, raises this question. What do you, the practicing psychiatrist, think?
My impression is that we can learn a lot by asking the question and considering the possibility that the differences between schizophrenia and either psychotic bipolar disorder or psychotic mood disorder are different points on a severity spectrum, but we do not have enough evidence to make that leap. There are certainly areas, such as the overlap between bipolar disorder and unipolar depressions, that seem to increasingly overlap, based on a number of studies published over the past 5 to 10 years. The treatment of psychotic mood disorders certainly overlaps with the treatment of schizophrenia, both involving the use of new generation antipsychotic medications. There is no doubt that the schizophrenia diagnosis is a protean diagnosis — but what about the deficit state and severe negative symptoms. Is there any clarity that they are related to a mood disorder? It seems likely that patients with psychotic mood disorders can be misdiagnosed as schizophrenia (as illustrated by Dr. Lake). But that alone is not sufficient to consider all patients with schizophrenia as having a psychotic bipolar or mood disorder.
This is a useful debate, and, hopefully, more information will be brought to bear as we learn more. Hopefully, we will someday know enough about the psychobiology of these disorders to get beyond symptom description as a basis for our diagnoses and treatment choices.