Polysomnographic measures of sleep in cocaine dependence and alcohol dependence: Implications for age‐related loss of slow wave, stage 3 sleep

BACKGROUND AND AIMS Sleep disturbance is a prominent complaint in cocaine and alcohol dependence. This controlled study evaluated differences of polysomnographic (PSG) sleep in cocaine- and alcohol-dependent subjects, and examined whether substance dependence interacts with age to alter slow wave sleep and rapid eye movement (REM) sleep. DESIGN Cross-sectional comparison. SETTING Los Angeles and San Diego, CA, USA. PARTICIPANTS Abstinent cocaine-dependent subjects (n = 32), abstinent alcohol-dependent subjects (n = 73) and controls (n = 108); mean age 40.3 years recruited 2005-12. MEASUREMENTS PSG measures of sleep continuity and sleep architecture primary outcomes of Stage 3 sleep and REM sleep. Covariates included age, ethnicity, education, smoking, body mass index and depressive symptoms. FINDINGS Compared with controls, both groups of substance dependent subjects showed loss of Stage 3 sleep (P < 0.001). A substance dependence × age interaction was found in which both cocaine- and alcohol-dependent groups showed loss of Stage 3 sleep at an earlier age than controls (P < 0.05 for all), and cocaine-dependent subjects showed loss of Stage 3 sleep at an earlier age than alcoholics (P < 0.05). Compared with controls, REM sleep was increased in both substance-dependent groups (P < 0.001), and cocaine and alcohol dependence were associated with earlier age-related increase in REM sleep (P < 0.05 for all). CONCLUSIONS Cocaine and alcohol dependence appear to be associated with marked disturbances of sleep architecture, including increased rapid eye movement sleep and accelerated age-related loss of slow wave, Stage 3 sleep.