Alexithymia and polysomnographic measures of sleep in healthy adults

Objective: This study examined associations between alexithymia and objecti ve characteristics of sleep (latencies, stages, and amount and patterning o f REM sleep) that may contribute to subjective reports of poor sleep qualit y and impaired dream recall among alexithymic people. Methods: Fifty health y, normally sleeping adults from the community completed the 20-item Toront o Alexithymia Scale and slept uninterrupted for one night in the laboratory while polysomnography was conducted. Various measures of sleep latency, sl eep stages, and REM sleep-related variables were obtained, and analyses cor related these sleep measures with alexithymia, controlling for age, sex, an d level of depressed affect. Results: Higher alexithymia scores were signif icantly related to increased stage 1 (light) sleep and decreased stage 3/4 (deep) sleep. Alexithymia was unrelated to overall sleep efficiency or perc entage of stage 2 sleep. Alexithymia was related to more frequent REM episo des and more stage 1 sleep during and immediately after REM episodes but wa s unrelated to the absolute amount of REM sleep. Alexithymia was also relat ed to an earlier onset of the first REM episode. Conclusions: Alexithymia i s associated with more light sleep and less deep sleep, which may contribut e to subjective reports of poor sleep and increased sleepiness, fatigue, an d somatic symptoms. Although alexithymia is not associated with an overall reduction of REM sleep, the increased frequency of episodes of REM that are interrupted and followed by light sleep rather than complete awakenings ma y contribute to limited dream recall.