Mood-dependent fluctuations in the severity of tardive dyskinesia and psoriasis vulgaris in a patient with schizoaffective disorder: possible role of melatonin.

There is evidence that patients with affective disorders are at high risk for developing Tardive dyskinesia (TD). In addition, in patients with bipolar illness, depressive episodes have been associated with exacerbation of the TD, while manic episodes were accompanied by attenuation of TD. Since depression is associated with diminished melatonin secretion, the high incidence of TD in patients with history of depression may be linked to diminished secretory activity of the pineal melatonin. We report a 28-year old female patient with schizoaffective disorder associated with psoriasis vulgaris in whom periodic exacerbation of depressive moods and suicidal thoughts were accompanied by worsening of the TD as well as the psoriatic lesions. Spontaneous improvements of mood were associated with disappearance of the involuntary movements and regression of the psoriatic lesions. Since melatonin secretion is diminished in patients with depression and in patients with psoriasis vulgaris, this report may add further support to the hypothesis that the development of TD may be associated with diminished secretory activity of pineal melatonin. The mechanisms by which diminished melatonin secretion may facilitate the emergence of TD are discussed. In addition, the possibility that light therapy, as has been successfully used in the management of seasonal affective disorders, may be useful in the management and perhaps prophylaxis of TD is discussed.