Subjective sleep, depression and anxiety: Inter-relationships in a non-clinical sample

Objectives: Previous research confirms the interdependent relationship between poor sleep and depression, but has often focused on objective measures of sleep and overlooked the importance of subjective factors. Insomnia may be maintained by anxiety and perceptions of poor sleep timing, and depression is associated with poor sleep satisfaction, regardless of perceived sleep timing. Methods: This study explored the contribution of current depression and anxiety to sleep perceptions. Participants (n=98) completed the Hospital Anxiety and Depression scale, and questionnaires were used to evaluate current and previous psychiatric illness, sleep disorders and prescribed psychotropic medication. Results: A series of ANOVAs and regression analyses indicated that variance in sleep timing perceptions was more likely to be explained by symptoms of anxiety than depression; explained variance (adj. R2) 25%, 1=2.361; p=0.023. The analyses also showed that sleep satisfaction perceptions (adj. R2=20%, 1=3.085; p=0.004), and those relating to overall quality of life (adj. R2=37%, t=-2.763; p=0.013), were more likely to be explained by symptoms of depression. Conclusions: These findings support the observation that anxiety appears related to poorer sleep timing perceptions, while depression appears associated with poor sleep satisfaction. Further research is needed to explore the factors that might maintain poor sleep satisfaction in depression. Copyright © 2009 John Wiley & Sons, Ltd.