A quote attributed to Benjamin Franklin reads, “An ounce of prevention is worth a pound of cure.” With this in mind, the goal of psychiatry continues to be to identify early signs of mental illness in order to initiate early treatment after it has been shown to be Meaningful treatment positively influences the results of many psychiatric illnesses. Indeed, there is an unmet need for preventive strategies that delay or prevent the onset of mental illness, especially among those at increased risk. Consequently, the researchers identified insomnia – a syndrome of chronic problems with falling asleep and / or sleep continuity associated with impaired daily function – as a possible predictor of emerging major depressive disorder in 2 meta-analyzes with odds ratios (ORs) of 2.3 to 184.108.40.206
Hertenstein and colleagues3 conducted a systematic, quantitative review of longitudinal studies to investigate whether initial insomnia (including symptoms during the night and during the day) is associated with subsequent onset of a mental disorder. Study authors searched for articles in PubMed, Medline, PsycInfo, and PsycArticles, as well as reference lists of identified studies and recently published congress abstracts.
Longitudinal studies were included if they met the following criteria: follow-up lasted at least 12 months in adults diagnosed with insomnia based on interview or questionnaire (covering both nocturnal and daytime symptoms); Diagnoses of mental disorders were verified through clinical interviews or validated self-assessment questionnaires; and either participants with mental disorders other than baseline insomnia were excluded, or the study was controlled for baseline psychopathology. The data were analyzed using the random effects meta-analysis. Effect sizes (ORs) were calculated for individual mental disorders as well as for all mental disorders combined. The authors performed assessments of both risk of bias and publication bias.
The authors identified 13 studies with a total sample of 181,798 participants at the start of the study and 133,967 participants at the last follow-up. These studies included 10 samples for depression, 6 for anxiety, 2 for alcohol abuse, and 1 for psychotic disorders. The average study duration was 61 months. They found that baseline insomnia was associated with a significantly increased likelihood of occurrence of depression (OR, 2.8), anxiety (OR, 3.2), alcohol abuse (OR, 1.4) and psychosis (OR, 1.3 ) was connected.
In all pooled studies, baseline insomnia was associated with a significant 2.6-fold increased risk of mental disorders, with evidence of significant heterogeneity between studies. Overall, the risk of bias for most of the individual studies was classified as moderate. There was no significant evidence of publication bias for depression or anxiety. There was no evidence that study duration moderated these associations. In addition, the pattern of findings did not change in a subgroup analysis of studies with participants without mental disorders at the start of the study.
The authors concluded that baseline insomnia was associated with a significantly increased likelihood of mental disorders. Possible explanations for these associations include brain hyper-arousal, neuroplasticity, and emotion regulation. A strength of the meta-analysis is that inclusion required both nocturnal and daytime symptoms of insomnia that meet current diagnostic criteria. The authors found, however, that the observed temporal relationship does not allow any causal attributions. Nonetheless, the results indicate the possibility of insomnia treatment for the prevention of mental disorders.
Dr. Miller is a professor in the Department of Psychiatry and Health Behavior at Augusta University, Augusta, Georgia. He is the director of schizophrenia for the Psychiatric Times ™. The author reports that he has received research funding from Augusta University, the National Institute of Mental Health, the Brain and Behavior Research Foundation, and the Stanley Medical Research Institute.
1. Baglioni C, Battagliese G, Feige B, et al. Insomnia as a Predictor of Depression: A Meta-Analytical Evaluation of Longitudinal Epidemiological Studies.
J influence disturbance. 2011; 135 (1-3): 10-19.
2. L. Li, C. Wu, Y. Gan et al. Insomnia and the risk of depression: a meta-analysis of prospective cohort studies. BMC Psychiatrist 2016; 16 (1): 375.
3. Hertenstein, E., Feige, B., Gmeiner, T., et al. Insomnia as a Predictor of Mental Disorder: a Systematic Review and Meta-Analysis. Sleep Med Rev 2019; 43: 96-105.