Studies of nocturnal penile tumescence and sleep electroencephalogram in patients with major depression and in normal controls.

Nocturnal penile tumescence (NPT), sleep electroencephalogram and testosterone secretion were investigated in 25 nonmedicated male patients with an acute episode of major depression. Twelve patients were reassessed after a stable remission and withdrawal of antidepressants. Four of the 25 patients had no NPT activity during acute depression, but this was reversed after recovery. The area under the NPT curve increased after remission, whereas all other NPT variables remained unchanged. Nocturnal testosterone secretion was enhanced after recovery, whereas the sleep structure remained unchanged. The NPT findings for the depressed patients did not differ from those for a control group, even though the latter group was younger. Hence, there are no general NPT changes that could be used to separate depressed patients and normal controls. However, a lack of NPT seems to be a possible, reversible symptom of depression in men.