Alexithymia and polysomnographic measures of sleep in healthy adults.

OBJECTIVE: This study examined associations between alexithymia and objective characteristics of sleep (latencies, stages, and amount and patterning of REM sleep) that may contribute to subjective reports of poor sleep quality and impaired dream recall among alexithymic people. METHODS: Fifty healthy, normally sleeping adults from the community completed the 20-item Toronto Alexithymia Scale and slept uninterrupted for one night in the laboratory while polysomnography was conducted. Various measures of sleep latency, sleep stages, and REM sleep-related variables were obtained, and analyses correlated these sleep measures with alexithymia, controlling for age, sex, and level of depressed affect. RESULTS: Higher alexithymia scores were significantly related to increased stage 1 (light) sleep and decreased stage 3/4 (deep) sleep. Alexithymia was unrelated to overall sleep efficiency or percentage of stage 2 sleep. Alexithymia was related to more frequent REM episodes and more stage 1 sleep during and immediately after REM episodes but was unrelated to the absolute amount of REM sleep. Alexithymia was also related to an earlier onset of the first REM episode. CONCLUSIONS: Alexithymia is associated with more light sleep and less deep sleep, which may contribute to subjective reports of poor sleep and increased sleepiness, fatigue, and 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 may contribute to limited dream recall.

The relationship of alexithymia characteristics to dreaming.

OBJECTIVE: In two studies, we tested two hypotheses about the relationship of alexithymia to dreaming; that dreams of alexithymic people are barren and rarely recalled, and that the dreams are unregulated and nightmarish. METHODS: Study 1 was a retrospective survey of dreaming among several hundred young adults, and Study 2 was a 1-week, prospective diary study of 153 young adults in which recall, content, and length of dreams were assessed. RESULTS: Across both studies, the externally oriented thinking (EOT) facet of the Toronto Alexithymia Scale (TAS)-20 correlated with different dream characteristics than the difficulty identifying feelings (DIF) and difficulty describing feelings (DDF) facets, even after statistically controlling for the other facets. Greater EOT was related to an increased frequency of nights without dream recall, having shorter dreams, having dreams rated as boring and lacking vividness, and not believing in the importance of dreams. In contrast, greater DIF or DDF was related to an increased frequency of nights with disturbing dreams, and having dreams rated as bizarre and aggressive. CONCLUSION: We find support for both hypotheses, but different facets of the multidimensional alexithymia construct account for the two types of dream reports.