To the Editor.—
The possible biochemical heterogeneity of affective disorders has been discussed during the last decade.1 The bimodal distribution of 5-hydroxyindoleacetic acid (5-HIAA) in cerebrospinal fluid (CSF) supports the hypothesis that a subgroup of endogenous depressives have a disturbance in serotonin neurotransmission.2Moreover, significantly lower homevanillic acid (HVA) levels in the CSF were found in depressed patients compared with healthy control subjects.3 This finding and results from other studies indicate that dopamine might be involved in the pathogenesis of affective disorders.3 The antidepressant effect of the dopamine agonists bromocriptine6,7 and piribedil8 supports this hypothesis. Silverstone7 has shown that patients with bipolar but not unipolar depression responded to bromocriptine. This indicates that bipolar and unipolar depression might differ in central dopaminergic neurotransmission.
Patients and Methods.—
Our study group comprised 50 nontreated patients (age range, 24 to 73 years; 21 men and 29 women)