Sleep and circadian rhythms as possible trait markers of suicide attempt in bipolar disorders: An actigraphy study

Background: The poor prognostic of Bipolar disorders (BD) is closely linked to deaths by suicide. Sleep and circadian abnormalities are observed during all phases of BD and are also associated with suicide attempt (SA). In this context, this study sought to identify specific sleep and circadian rhythms markers associated with suicidal attempt in euthymic patients with BD. Methods: The sample (N = 236) comprised 3 groups: 147 patients with BD including 57 with a history of SA and 90 without (NoSA), and 89 healthy controls (HC). All participants were recorded during 21 days with actigraphy. Results: SA was associated with women gender (p = 0.03), familial history of SA (p = 0.03), mixed episodes (p = 0.001), and benzodiazepines (p = 0.019). SA, compared to noSA, had a morning phase preference (p = 0.04), and were more vigorous on the circadian type inventory (p = 0.04), and tended to suffer more from insomnia (45% versus 25% respectively, p = 0.10). SA was also associated with an earlier onset of daily activity assessed with actigraphy (M10 onset: p = 0.01). Backward stepwise linear regression indicated that a combination of four variables (Gender, vigour, insomnia, M10onset) significantly differentiated patients with SA from NoSA (p = 0.03). Limitations: Cross-sectional design, and no examination of suicidal behaviors' subgroups such as first attempters or repeaters, or violent suicide attempt. Conclusions: Woman gender, vigorous circadian type, insomnia and an earlier daily activity appeared independently associated with SA in BD. If these biomarkers are confirmed in prospective studies, they should be screened and used to prevent suicide, with the development of personal and targeted chronobiological treatments.