Principal Investigator:  Irwin Feinberg, M.D.

Adolescence is now recognized as a period of major brain-reorganization, in addition to rapid endocrine and physical development. Among the most prominent brain changes are reductions in total sleep and a huge decline in the amplitude and abundance of the delta EEG of NREM sleep. Other brain changes in adolescence include synaptic elimination and a reduction in cortical metabolic rate. Neurodevelopmental models posit that schizophrenia may be caused or unmasked by abnormalities in these maturational processes. Daytime sleepiness emerges in adolescence, impacting mood and school performance. However, a specific within-subjectstudy of the relation of daytime sleepiness to quantitative changes in sleep EEG waveforms has not been reported. There are other major gaps in our knowledge. We do not know the within-subject rates of change in the amplitude and incidence of EEG waves in delta and other frequencies, whether 'spurts' in delta decline normally occur, the shapes of the age curves, their relation to age vs. pubertal stage, and the extent of individual and gender differences. Our research aims to fill these gaps by studying sleep longitudinally in 2 age cohorts (ages 9-13 and 12-16 years) during the period of most rapid change. Baseline and extended sleep will be studied twice/yr for 4 years. EEG waveforms will be quantified with FFT-spectral and period amplitude analyses (the 2 most widely used computer methods) and with visual sleep stage scoring. Sleepiness will be assessed with the MSLT and behavioral ratings and mood will be systematically evaluated at each time point. The proposed research will help fill major gaps in our knowledge of one of the most pronounced maturational changes of the human brain, It will also test specific hypotheses regarding the : correlates of these changes. The data we acquire could shed light on concomitant brain changes, leading to the identification of new biological relationships. Our studies will also provide benchmark data for neurodevelopmental studies in psychiatrically ill adolescents and 'at-risk' population.