Wearable accelerometer data from over 89,000 participants indicated that people with a mental illness diagnosis were more likely to have poor sleep quality than the general population.
In investigating the relationship between sleep and mental health, sleep interventions have been cited to reduce the symptom burden of several mental illnesses, such as depression and posttraumatic stress disorder.
“We know that up to 80% of people with mental health disorders can have problems with falling asleep, staying asleep, or waking up earlier than they intended,” said Michael Mak, MD, FRCPC, psychiatrist at the Centre for Addiction and Mental Health (CAMH) and assistant professor of Sleep Medicine at the University of Toronto, in a statement.
“We know that sleep disturbances cause a great burden to society, including an economic one. And we know that treatments that improve sleep quality, whether it is therapy or some types of medication, can improve mental health outcomes," he continued.
Despite this association, prior studies have focused solely on self-reported measures of sleep when assessing mental illness risk, which may not always correlate well with direct physiological measurements.
Moreover, although the use of lab-based polysomnography (PSG) is the gold standard for sleep measurement, spending a night in a sleep clinic with multiple electrodes attached to one’s body may not be conducive to a good night’s sleep, added the study authors.
As an alternative to standard PSG, researchers leveraged wrist-worn accelerometers in their analysis, which provide objective measurements of sleep at scale and have been used in prior smaller studies, with conflicting findings. They examined the association of accelerometer-derived sleep measures with psychiatric diagnoses and polygenic risk scores in a cohort of 89,205 UK Biobank participants (56% female; 97% self-reported White) between 2013 and 2015.
In the post hoc cross-sectional analysis, the wearable accelerometer tracked participants’ body movement 24 hours a day for 7 days. These accelerometry recordings provided 10 interpretable sleep measures: bedtime, wake-up time, sleep duration, wake after sleep onset, sleep efficiency, number of awakenings, duration of longest sleep bout, number of naps, and variability in bedtime and sleep duration.
“These measures were examined for association with lifetime inpatient diagnoses of major depressive disorder, anxiety disorders, bipolar disorder/mania, and schizophrenia spectrum disorders from any time before the date of accelerometry, as well as polygenic risk scores for major depression, bipolar disorder, and schizophrenia,” said the study authors.
Across each mental illness diagnosis, the researchers found that affected patients were associated with a median 8.5 of the 10 accelerometer-derived sleep measures, although effect sizes were generally small.
Furthermore, their results indicated a stronger association between measures of sleep quality and mental illness diagnosis than sleep duration, particularly sleep efficiency in association with lifetime inpatient major depressive disorder diagnosis, which exhibited the largest magnitude effect size across the 4 diagnoses (β = −0.11; 95% CI, −0.13 to −0.10; P = 3 × 10−56; false discovery rate = 6 × 10−55).
The researchers said that associations were largely replicated across ancestries and sexes and accelerometry-derived measures were concordant with self-reported sleep properties.
“The relationship between sleep and mental health is bidirectional,” said lead study author Michael Wainberg, PhD, postdoctoral researcher at the Krembil Centre for Neuroinformatics, in a statement. “Poor sleep contributes to poor mental health and poor mental health contributes to poor sleep. Sleep pattern differences were a feature of all mental illnesses we studied regardless of diagnosis.”
Following the study findings, researchers noted plans to develop a CAMH BrainHealth Databank, designed similarly to the UK Biobank, which will use patient data collected either in-hospital or via remote wearable technologies to enhance personalized mental health care and accelerate future clinical research.
Wainberg M, Jones SE, Beaupre LM, et al. Association of accelerometer-derived sleep measures with lifetime psychiatric diagnoses: A cross-sectional study of 89,205 participants from the UK Biobank. PLoS Med. Published online October 12, 2021. doi:10.1371/ journal.pmed.1003782