This article is the fourth in the series. If you missed the first three and want to catch up, here they are:
- Sleep & Pain ... or is it Pain & Sleep
- Sleep and Weekend Recovery: Can You Catch Up?
- Sleep and Exercise: A Reciprocal Relationship
Sleep and mental health are closely linked, with sleep disruptions often accompanying and contributing to conditions such as mood disorders (e.g., depression), anxiety and poor coping capacity.
Epidemiological studies suggest that poor sleep increases the risk of developing mood disorders, while improving sleep can help alleviate psychological symptoms. A 2017 intervention study conducted by Freeman et al. which at the time was the largest randomised controlled trial of a psychological intervention (i.e., CBT for insomnia) for a mental health problem. The results provide strong evidence that insomnia is a causal factor in the occurrence of psychotic experiences and other mental health problems. The authors concluded that "the treatment of disrupted sleep might require a higher priority in mental health provision." (Freeman D 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).
Sleep architecture (i.e., the stages and organisation of sleep) plays a key role in emotional regulation. Rapid eye movement (REM) sleep, in particular, plays a crucial role in processing/integrating, and understanding emotional memories. Inadequate REM (i.e, quantity) or fragmented REM (i.e., quality) sleep may heighten emotional reactivity and reduce coping capacity. Furthermore, insomnia often precedes the onset of depressive episodes and can be a warning sign of an impending relapse. (Sweetman, et al., Co-occurring depression and insomnia in Australian primary care: recent scientific evidence. Med. J. Aust. 2021; 215(5)).
Recent neuroimaging studies have revealed that sleep deprivation affects brain regions involved in emotional regulation, including the amygdala and prefrontal cortex. A study by Goldstein and Walker (Nat Rev Neurosci. 2014;15(9):585–598) showed that sleep-deprived individuals had exaggerated amygdala responses to harmful stimuli, which were less effectively regulated by the prefrontal cortex.
Cognitive Behavioural Therapy for Insomnia (CBT-I) has shown consistent benefits for both sleep and mental health. Reported by the authors of a 2018 systematic review in Sleep Medicine Reviews, CBT-I improves sleep outcomes and reduces symptoms of depression and anxiety, with sustained effects over time (van Straten A et al. Cognitive and behavioural therapies in the treatment of insomnia: A meta-analysis. Sleep Med Rev. 2018;40:19 36). CBT-I is one of the key interventions taught in my Sleep Mastery course.
Improving sleep hygiene, addressing sleep disorders, and seeking psychological support when needed are crucial steps in enhancing mental well-being. Sleep should be considered a foundational pillar of mental health care, not just a secondary symptom or consequence of illness.