Tricyclics modulate frequency of mood cycles

In 5 female manic-depressive patients studied longitudinally, mood cycle frequency was markedly accelerated from 1 cycle/2-8 months to 1 cycle/1-6 weeks by tricyclic antidepressant drugs. In a sixth patient a similar effect was observed with a monoamine oxidase inhibitor (another major type of antidepressant medication). Affective disorders are inherently cyclic. In the group of patients reported here the action of 'antidepressant' drugs can be more broadly conceived as accelerating the entire cyclic illness process rather than counter-acting only one of its phases. The effect of these drugs on the spontaneous frequencies of other rhythmic biological processes should be explored.