Adolescents who are at risk for later episodes of major depressive disorders differ from their peers who are not at risk on multiple measures of rapid eye movement (REM) and hypothalamic-pituitary-adrenal (HPA) activity during sleep, according to a study by Uma Rao and colleagues that appeared this fall in Neuropsychopharmacology . Early depressive episodes that occur during adolescence are strongly associated with other later problems in other areas such as interpersonal relationships, pregnancy, educational attainment, employment, and suicidal behavior; finding predictors of later problems is important for primary and secondary prevention.
Rao and colleagues compared youths at risk for major depressive disorder with peers using electroencephalographic (EEG) and HPA measures. They then followed the youths for 5 years and correlated their EEG and HPA measures with the chances of later episodes of depression. Here’s the abstract:
Rao, U., Hammen, C. L., & Poland, R. E. (2009). Risk markers for depression in adolescents: Sleep and HPA measures. Neuropsychopharmacology, 34, 1936–1945.
Previous work has demonstrated reliable electroencephalographic (EEG) sleep and hypothalamic-pituitary-adrenal (HPA) changes associated with adult major depressive disorder. These changes might be evident before clinical manifestation of the illness in at-risk persons. The aim of the study was to identify depression-related EEG sleep and HPA changes in healthy adolescents at high risk for depression, and to examine the relationship between EEG sleep (or HPA) changes and the onset of depression. Forty-eight adolescent volunteers with no personal history of a psychiatric illness, including depression, but who were at high risk for developing depression by virtue of parental depression (high-risk group), and 48 adolescent volunteers with no personal or family history of a psychiatric disorder (normal controls) were recruited. EEG sleep and HPA measures were collected on three consecutive evenings and nights at baseline. Clinical follow-up evaluations were conducted at regular intervals over a 5-year period. Compared with normal controls, adolescents at high risk for depression had shorter latency to rapid eye movement (REM) sleep, increased phasic REM sleep, more REM sleep and elevated nocturnal urinary-free cortisol (NUFC) excretion at baseline. Shorter REM latency, higher REM density and elevated NUFC (measured at baseline) were associated with the development of depression during follow-up. The findings that REM sleep abnormalities and elevated HPA activity occur before the onset of depression in at-risk adolescents suggest that these variables serve as vulnerability markers for the illness.
These results do not mean that one can simply observe children when they sleep and decide whether they are at risk for adult depression. The REM and HPA predictors add to the estimate of risk based on a family history of depression; also, the same REM and HPA levels occur for some individuals who do not develop depression. The findings need replication (e.g., larger samples) and refinement (are both depression and sleep differences driven by some other, currently unknown factor?). The results may, however, help in developing pharmacologic interventions to decrease the chances of late-teen and adult episodes of depression.
Link the original source for this abstract.