New research is causing researchers to reassess the DSM’s view of mood disorders. Recently a Canadian researcher by the name of McIntyre performed a study that challenges the DSM model. McIntyre gave a neuroleptic, lurasidone, to two groups of bipolar patients. One group consisted of depressed individuals while the other consisted of those in a mixed state. Somewhat surprisingly the drug helped both equally which implies the two states aren’t all that different.
Additional research by John Geddes, chairman of Oxford University’s Department of Psychiatry at Oxford also supports the idea that the various states in bipolar disorder are more similar than different and that instability is the key feature. The idea of pure depression or pure mania in the DSM is idealistic and limits our understanding. In reality mood episodes usually consist of depressive and manic symptoms imposed on top of an unstable temperament instead of a completely euthymic mood.
This constant mood lability throws into doubt the entire DSM-based distinction between “bipolar” and “major depressive” disorders. It is instead consistent with Kraepelin‘s original view of manic-depressive insanity as a broad illness of recurrent mood episodes, irrespective of polarity (in other words, recurrent depression is manic-depressive illness even without classic manic episodes), in contrast to the current faith in bipolar disorder (mania is required) vs major depressive disorder (mania is absent).
Nassir Ghaemi concluded his article by suggesting that metanalysis on antidepressants efficacy are obscured by the fact that major depression is categorized too broadly and consequently there is too much heterogeneity. I believe he is suggesting that if depression is subcategorized to a greater degree the efficacy issue will be come much clearer. Perhaps antidepressants are more efficacious in one subtype than another? Additionally he suggests the opposite of most critics which is that bipolar disorder is too narrowly defined. I have had similar thoughts regarding the heterogeneity of depression and consequently I am in agreement.