Polysomnographic sleep patterns in depressive, schizophrenic and healthy subjects

Sleep disorders are frequent symptoms described in psychiatric patients with major depression and schizophrenia. These patients also exhibit changes in sleep architecture measured by polysomnography (PSG) during sleep. The aim of the present study was to identify potential biomarkers to facilitate diagnosis based on PSG measurements. Thirty (30) patients with schizophrenia, 30 patients with major depression and 30 healthy control subjects were investigated in the present study. All subjects underwent PSG measurements for a minimum time of 8 hours according to the criteria of Rechtscahffen & Kales (1968). We tested the potential of multiple sleep variables to predict diagnosis in different groups by using linear discriminant analysis (LDA). There were significant differences in PSG variables between healthy control subjects and psychiatric patients (total sleep time, sleep latency, number of awakenings, time of awakening after sleep onset, REM 1 latency, REM 1 and index of endogenous periodicity). Importantly, LDA was able to predict the correct diagnosis in 88% of all cases. The presented analysis showed commonalities and differences in PSG changes in patients with major depressive disorder and in patients with schizophrenia. Our results underline the potential of PSG measurements to facilitate diagnostic processes.