Sleep Pattern Variations as a Function of Age in Affective Disorders

Abstract

Polygraphic features of nocturnal sleep were evaluated in young adult psychiatric patients during acute unipolar depressive episodes. Averaged values and variability of polygraphic indexes were examined in 12 depressed patients under the age of 26 individually matched with a normal control group. Sleep was polygraphically recorded in the Laboratory for three consecutive nights from 12–8.00 a.m. Although average total time asleep was approximately equivalent (>7.3 hr) between groups, depressives accumulated significantly: (i) less stage 4, (ii) more stage 1, (iii) vascillations among sleep stages, but (iv) most especially increased transitions into stage 1 and (v) intermittent wakefulness. The recorded sleep perturbations in young depressives were extremely variable across nights and among individuals. This was especially conspicuous across nights as reflected by significantly larger variability (SD) for: (i) transitisons into stage 1, (ii) intermittent wakefulness and (iii) ∑ accumulations of stage 2. Variability (the SD) between individuals was also more substantial for: (i) total time asleep, (ii) stage 1, (iii) intermittent wakefulness, (iv) ∑ stage shifts and (v) intrusions into stage 1. The polygraphic recordings of young depressives contained anomalies reported for clinical pathologic states accompanied by physiological disregulation such as hypersomnia, narcolepsy and schizoaffective disorders. Polygraphic indexes reflecting the capacity (i) to remain asleep (X ± SDs) and (ii) accumulate continuous sleep (SDs) indicated an imbalance of the 24-hr rest (sleep) — activity (waking) cycle was present in this constituency concomitant with affective distress. A comparison with selected cross-sectional polygraphic studies revealed that sleep cycle aberrations in young adult depressives were less intense than those which become exacerbated as a function of advanced age. By contrast to prepubertal children or postadolescent young adults who are depressed, elderly accumulate: (i) lower total sleep times, (ii) less proportions of stages 3-4 and (iii) remain awake longer. It is concluded that sleep-polygraphic anomalies in postadolescent depression are an attenuated form of the REM-NREM cycle perturabation endemic to affective disease occurring with advanced age or senescence.