Association Between the Tryptophan Hydroxylase Gene and Manic-depressive Illness

Abstract

THERE IS compelling evidence that abnormalities of serotonergic neurotransmission contribute to depression. The major serotonin (5-hydroxytryptamine [5-HT]) metabolite is 5-hydroxyindoleacetic acid (5-HIAA), and its concentration is low in the cerebrospinal fluid of a subgroup of patients with unipolar depression who attempted suicide by violent means.^1,2 Furthermore, platelet 5-HT uptake is diminished in patients with depression³ and especially in patients with bipolar disorder.^4,5 Reduced binding of tritiated imipramine or tritiated paroxetine to brain 5-HT uptake sites and transporters has been found in patients with depression⁶ and in suicide victims.⁷