GH1 and major depressive disorder: Dahl et al. (1992) found no difference in GH levels between adolescents with MDD and the control. However, the MDD group with suicidal behavior (defined as having detailed plans or attempts) had reduced sleep GH secretion compared to the group without suicidal behavior. Abnormalities in the GH axis may be limited to preadolescent children with depression (Zalsman et al., 2006), but the role of GH in adolescent suicide is unclear and requires further study.