Nocturnal growth hormone secretion studies in adolescents with or without major depression re-examined: Integration of adult clinical follow-up data

Background: Early sleep is associated with an increased secretion of human growth hormone (GH) through muscarinic inhibition of somatostatin, a GH sup pressant, A clinical follow up was performed approximately I decade after d epressed and psychiatrically "normal" control adolescents, who were now you ng adults, had undergone baseline serial GH measurements over a 24-hour per iod on the third! night of sleep polysomnography studies. Methods: The study population consisted of 77 young adults who had received a diagnosis of adolescent major depressive disorder and had participated i n the adolescent sleep and neuroendocrine studies. Alternatively, the young adult subjects were assessed as normal adolescent control subjects free of any psychiatric diagnosis. Blood samples had been collected for GH every 2 0 min during the 24-hour period coinciding with the third consecutive night of sleep electroencephalography. Subjects, now in young adulthood were rel ocated and relocated reinterviewed ed using the Schedule for Affective Diso rders and Schizophrenia (lifetime version). The original adolescent nocturn al GH data were analyzed in Eight of the information obtained regarding cli nical course into adulthood. Results: A substantial proportion of the nominally normal control group dev eloped at least one episode of major depression or dysthymia during the fol low-up period. "Latent" depressive subjects differed from depression-free c ontrol subjects by having exhibited a significantly more rapid increase of adolescent nocturnal GH secretion following sleep onset. Of the subjects wh o had experienced at least one lifetime major depressive episode during rit e follow-up, the-subgroup, who would go on to make suicide attempts secrete d significantly greater amounts of GH during the first 4 hours of sleep. Ad ults with lifetime depression exhibited significantly reduced levels of GH in the 100 min preceding sleep onset during adolescence. Conclusions: Assignment of subjects based on longitudinal clinical follow-u p into adulthood revealed that the sleep-related GH secretion paradigm has predictive value for future depressive episodes and future suicide attempts . Dysfunction of complex sleep-onset mechanisms may? be a premorbid marker of depression ann suicidal behavior. (C) 2000 Society of Biological Psychia try.