Disrupted sleep tied to alexithymia

Heightened alexithymia may explain poor sleep quality, a pair of studies shows.

Alexithymia is a condition characterized by difficulty identifying and expressing one’s emotions. “The mechanism by which alexithymia confers risk of disrupted sleep remains unclear, [but] suggestions include increased nocturnal arousal as a result of poor verbalization of emotions and increased light sleep,” wrote Jennifer Murphy, citing previous research.

©KatarzynaBialasiewicz/Thinkstock

In the first study, Ms. Murphy and her associates recruited 86 men and women; 70 were included in the analyses. Participants’ alexithymia scores were measured using the Toronto Alexithymia Scale, or TAS-20, which consists of three subscales – difficulty describing feelings, difficulty identifying feelings, and externally oriented thinking. Sleep quality was measured using the Pittsburgh Sleep Quality Index, or PSQI, a self-report measure that asks numerous questions, including: “During the past month, when have you usually gone to bed at night?” High scores on the TAS-20 and PSQI “indicate elevated alexithymic traits and poor sleep quality, respectively,” wrote Ms. Murphy, a doctoral candidate in social, genetic, and developmental psychiatry at King’s College London, and her associates in the journal Personality and Individual Differences.

The researchers found associations between total alexithymia scores and reduced sleep quality (P less than .001). They also found a significant association between the TAS-20 subscales and reduced sleep quality (all P less than .006).

In the second study, in which 73 men and women participated, Ms. Murphy and her associates sought to determine whether the association found in the first study was tied to depression or anxiety. Participants went online and completed three questionnaires: the TAS-20; the PSQI; and the Depression, Anxiety, & Stress Scale, or DASS-21, in a randomized order. Higher scores on the DASS-21 correlate with greater levels of depression, anxiety, and stress. None of the questionnaires asked about any aspects of sleep.

Jennifer Murphy

Using a regression model, Ms. Murphy and her associates found that all of the measures correlated with poor sleep quality. But only depression (P = .011) and alexithymia (P = .004) explained unique variance in sleep quality.

Ms. Murphy said in an interview that although it might be too early to make a clear clinical recommendation, the results suggest that “clinicians should be aware of the possibility of sleep problems characterized by heightened alexithymia and more generally in those with alexithymia.”