Clinical characterization of depressive mixed state in bipolar-I patients: Pisa-San Diego collaboration.

BACKGROUND Although mixed states were classically described as various concomitant admixtures of depression and mania, the official current definitions in both DSM-IV and ICD-10 tend to restrict the concept to manic patients with full syndromal depression. Recent research has actually shown that mania with few depressive symptoms constitutes the most prevalent clinical presentation of mixed or dysphoric mania. Major depressive patients with few concomitant manic symptoms are not officially recognized within the current nosology. In this paper we attempt to delineate the clinical profile of such depressive mixed states in the context of bipolar I disorder. METHODS In the Pisa day center, we studied 195 bipolar I patients who either met Pisa criteria for bipolar mixed state (n=159) or DSM-III-R criteria for major depressive episode (bipolar major depression or B-MD, n=36). Of the 159 patients identified by Pisa criteria as mixed state, 86 also met the criteria of the DSM-III-R for mixed episode (core mixed state or MS group), while 32 met the DSM III-R criteria for major depressive episode (provisionally defined as depressive mixed states, D-MS); the remaining patients (n=41, 25.7%) with predominatly manic picture were not included in the present comparisons. RESULTS The three groups (B-MD, MS and D-MS) had close similarities in clinical and sociodemographic characteristics such as age, sex distribution, marital status, schooling, residence, age at onset, age of first treatment, age of first hospitalization, degree of chronicity of the index episode, stressor within the 6 months before the index episode, lifetime suicide attempts and premorbid temperament. First degree family history for bipolar illness and that for other mental disorders was also similar, except for major depression that was more common among the relatives of D-MS. MS and D-MS were further distinguished from B-MD by the fact that the latter followed a more 'cyclic' course with shorter yet greater number of episodes, and which began with a pure depressive episode; by contrast, MS and D-MS had fewer episodes of longer duration, less interepisodic remission, and tended to begin with a mixed episode. Incongruous psychotic features were more common in the two mixed groups compared to B-MD, and the most common features of the D-MS group were agitation, psychotic depression with irritable mood, pressured speech and/or flight of ideas. LIMITATION It was not feasible to collect information blind to clinical status in patients with severe psychotic mood states. CONCLUSION These data confirm the existence of psychotic agitated depressive mixed states with flight of ideas, distinct from cyclic retarded pure bipolar depressive states. The recognition of these affective states is clinically important to protect patients from the potentially harmful indiscriminate use of antidepressants and to provide them with the benefits of an anticonvulsant, a short-term neuroleptic, or ECT.