Neuroendocrine correlates of depression in abstinent heroin-dependent subjects

The functions of the central alpha -adrenergic, serotoninergic and dopamine rgic systems were investigated in 28 heroin-dependent subjects 6-8 weeks af ter detoxification, and in 22 healthy control subjects (group C), Fourteen heroin-dependent subjects with depressive comorbidity (group A), and 14 her oin-dependent subjects without other Axis I and II pathologies (group B) we re included among; abstinent substance abusers. Norepinephrine (NE) functio n was evaluated by growth hormone (GH) responses to acute stimulation with clonidine (clon); serotonin (5-HT) function by prolactin (PRL) and cortisol (CORT) responses to acute stimulation with D-fenfluramine (D-fen) and dopa mine (DA) function by GH and PRL. responses to acute administration of brom ocriptine (brom). Central NE activity, as measured by the GH-clon test, see ms to be well preserved both in A and B subjects. PRL and CORT responses to D-fen were significantly blunted both in A subjects and in B subjects, in comparison with control subjects (C); the PRL response in A subjects was si gnificantly lower than in B subjects. The DA system of B subjects was found unimpaired; in contrast, a significantly higher GH response to brom in A s ubjects (depressed) could express D2 post-synaptic receptor hypersensitivit y and, therefore, decreased pre-synaptic DA release. In sum, the study of c entral monoamine function revealed an alteration only of the 5-HT system in detoxified heroin-dependent subjects without psychiatric comorbidity, whic h might be a trait character of these subjects, possibly involved in the pa thogenesis of the disorder. A more significant impairment of 5-HT function and the hypersensitivity of post-synaptic DA receptors in A subjects sugges ts that specific biological correlates of psychiatric comorbidity may chara cterize substance abuser subtypes. (C) 2000 Elsevier Science Ireland Ltd. A ll rights reserved.