Sleep Matters in Chronotype and Mental Health Association: Evidence from the UK and Germany.

Background: There is considerable evidence supporting the elevated risk of mental health problems in individuals with evening chronotype relative to those with morning or intermediate chronotypes. Recent data, however, suggest that this risk may be explained, at least partially, by poor sleep quality.

Methods: This study aimed to further clarify the roles of chronotype and sleep quality in mental health outcomes (depression, anxiety, stress) in young individuals (18-40 years) living in the UK (n = 185) or Germany (n = 209).

Results: Consistent with our recent observations in a comparable North Indian sample, we found that poor quality of sleep had significantly positive associations with adverse mental health outcomes both in the UK and Germany-based samples. Significant associations between evening chronotype and poor mental health were also evident, but these associations were fully mediated by poor quality of sleep in both samples.

Conclusions: These observations suggest that efforts to identify sleep disruption in a timely manner and promotion of good sleep may prevent mental health problems, especially in individuals with evening chronotype and other known risks for mental disorders.