Findings from a study conducted in the United Kingdom indicate that insomnia may be a cause of psychotic symptoms and other mental health problems. These results were published in Lancet Psychiatry.
Sleep problems are common in patients with mental health disorders. However, the conventional view has been that they are a symptom rather than a cause of these disorders, and therefore the treatment of sleep problems has been given a low priority. An alternative view is that disturbed sleep results in an escalating cycle of mental health symptoms, affecting daytime functioning and resulting in a struggle to gain restorative sleep. However, to date it has not been clearly established whether sleep problems are a consequence of or a contributory factor to mental health disorders.
OASIS was a single-blind randomized controlled trial conducted at 26 universities in the United Kingdom in 3755 students with insomnia between March 5, 2015 and February 17, 2016. Participants were randomly assigned to receive six 20-minute sessions of digital cognitive behavioral therapy (CBT) (n=1891) or usual practice (n=1864).
At 10 weeks, CBT reduced insomnia (adjusted difference 4.78; P <.0001), paranoia (–2.22; P <.0001) and hallucinations (–1.58; P <.0001) compared with usual practice.
The small, sustained reductions in paranoia and hallucinations in students assigned to CBT suggest that disrupted sleep plays a contributory causal role in these psychotic experiences in young adults. Furthermore, the mediation analyses support this conclusion, as sleep improvement accounted for nearly 60% of the change in paranoia. Improvements were observed particularly in depression, but also in anxiety, psychological well-being, nightmares, and perceived functioning.
Overall, the results of this trial highlight the importance of sleep difficulties for mental health problems and the need to reconsider the priority given to improving sleep.
There are a number of limitations to this study. The study relied on self-report questionnaires; participants were at the non-clinical end of the psychosis spectrum; participants were self-selecting; the extent to which these results can be generalized to other populations of patients with mental health disorders is unknown; and most notable, the high dropout rate in the treatment group introduced bias. While 1302 participants (69%) received 1 CBT session, only 331 subjects (18%) received all 6 CBT sessions. Nevertheless, it must be noted that beneficial treatment effects were greater in patients who completed the sleep therapy.
Freeman D, Sheaves B, Goodwin GM, et al. The effects of improving sleep on mental health (OASIS): a randomised controlled trial with mediation analysis. Lancet Psychiatry. 2017;4(10):749-758.