Bipolarity is important during treatment with antidepressants.

Rubino et al have identified that most (if not all) of the excess risk of suicide in a group of patients treated with venlafaxine could be explained by a higher burden of risk factors for suicide. It may be true that this group of patients had more severe or " difficult to treat " unipolar depression, but it is also possible that bipolar features in this group may be responsible for the observed raised rates of suicidality. Perhaps because of limitations of space, the authors do not discuss this as a possibility, despite an adjusted relative risk of completed suicide of 4.94 (95% confidence interval 1.30 to 18.84) for " past history of bipolar disorder " (table 3). 1 Recent work shows that at least 50% of difficult to treat unipolar depressed patients may have an undetected bipolar disorder, 2 and it is now well documented that antidepressant monotherapy for bipolar depression runs a high risk of precipitating hypomanic or mixed affective states, 3 which have been strongly associated with self harm and completed suicide. 4 It is also the case that venlafaxine seems more likely than other antidepressants to precipitate a switch into hypomania or mania in bipolar depression. 5 Furthermore, many of the variables reported by Rubino et al could be considered to point towards high levels of bipolarity in the venlafaxine treated group, including higher rates of a family history of psychiatric disorder, more frequent prescription of antipsychotics and mood stabilisers, a history of non-response to several different antidepressants, and more frequent lifetime depressive episodes.