Sachs et al. (April 26 issue)1 report that adding an adjunctive antidepressant drug offers no benefit over continued mood-stabilizer monotherapy in the treatment of bipolar depression. This finding contradicts some previous studies and the experience of many clinicians. In his thoughtful accompanying editorial, Belmaker2 identifies possible reasons for this discrepancy, including diagnostic heterogeneity and changes in the manifestation of bipolar disorder during the past 20 years. These observations are perhaps too circumspect.
The past two decades have seen a marked increase in the diagnosis of bipolar disorder by North American psychiatrists.3 This trend has many origins: a reaction to past underdiagnosis, a belief that this disorder is more treatable and less stigmatizing than some alternative diagnoses, and an insufficiently critical application of the diagnostic criteria of the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV), as well as a genuine conviction on the part of some authorities that this is indeed a widely prevalent condition.4 More recently, direct-to-consumer advertising by pharmaceutical companies has exacerbated the trend. To the extent that the diagnostic boundaries of bipolar disorder are allowed to expand, the benefits of specific pharmacologic treatments are likely to decline.