Factors associated with response to lithium prophylaxis in DSM III major depression and bipolar disorder.

The relationship of some clinical, personality and biological variables to the outcome of lithium prophylaxis was investigated in two patient samples fulfilling, respectively, the DSM III definitions of "major depression, recurrent" and "bipolar disorder". In major depressives, the presence of psychomotor retardation and melancholia during the index episode was associated with a favorable response to treatment, whereas the presence of mood-incongruent psychotic features during the same episode, a high score on the "anxiety" and "phobic" subscales of the Middlesex Hospital Questionnaire and a high score on the "neuroticism" subscale of the Eysenck Personality Questionnaire were related to a poor response. These findings are discussed in the light of the heterogeneity of DSM III major depression and of the reported common occurrence of an "anxiety-phobic" personality profile in unipolar depressives. In bipolar patients, a family history of bipolar affective illness and a high lithium ratio were associated with a good response to treatment, and the presence of the HLA-A3 antigen with an unfavorable response. These findings seem to support a role of pharmacogenetic factors in conditioning response to lithium prophylaxis.