Is Insomnia a Predictor of Mental Illness?
A quote attributed to Benjamin Franklin is “An ounce of prevention is better than a cure.” With this in mind, the field of psychiatry continues to aim to identify early indications of mental illness to initiate early treatment, as prompt treatment has been shown to positively affect the outcome of many psychiatric disorders. Indeed, there is an unmet need for preventive strategies that delay or prevent the onset of mental illness, particularly in those at increased risk. Therefore, the researchers looked at insomnia – a syndrome with chronic problems related to falling asleep and / or sleep continuity that are associated with impaired daytime functioning – as a potential predictor of major depressive disorder. of recent appearance in 2 meta-analyzes with odds ratios (OR) of 2.3 to 126.96.36.199
Hertenstein and his colleagues3 performed a systematic quantitative review of longitudinal studies, seeking to determine whether baseline insomnia (including nocturnal and daytime symptoms) is associated with subsequent onset of a mental disorder. The study authors searched PubMed, Medline, PsycInfo, and PsycArticles, as well as reference lists of identified studies and recent conference abstracts.
Longitudinal studies were included if they met the following criteria: follow-up lasted at least 12 months for adults diagnosed with insomnia, based on an interview or questionnaire (and covering at least both nocturnal and daytime symptoms); diagnoses of mental disorders were verified by clinical interviews or validated self-report questionnaires; and either participants with mental disorders other than insomnia at baseline were excluded or the controlled study for baseline psychopathology. Data were analyzed using a random effects meta-analysis. Effect sizes (OR) were calculated for individual mental disorders as well as for all mental disorders combined. The authors assessed both risk of bias and publication bias.
The authors identified 13 studies, comprising a total sample of 181,798 participants at baseline and 133,967 at last follow-up. These studies included 10 samples for depression, 6 for anxiety, 2 for alcohol abuse, and 1 for psychotic disorders. The mean duration of study follow-up was 61 months. They found that baseline insomnia was associated with a significantly increased risk of incident depression (OR, 2.8), anxiety (OR, 3.2), alcohol abuse (OR, 1, 4) and psychosis (OR, 1.3).
In all the studies pooled, baseline insomnia was associated with a significantly increased 2.6-fold likelihood of mental disorders, with evidence of significant heterogeneity between studies. Overall, the risk of bias was rated as moderate for most of the individual studies. There was no significant evidence of publication bias for depression or anxiety. There was no evidence that the duration of the study moderated these associations. In addition, the pattern of results did not change in a subgroup analysis of studies of participants without any mental disorder at baseline.
The authors concluded that baseline insomnia is associated with significantly increased risks of incident mental disorders. Potential explanations for these associations include brain hyperarousal, neuroplasticity, and emotional regulation. One of the strengths of the meta-analysis is that nocturnal and daytime insomnia symptoms were required for inclusion, according to current diagnostic criteria. The authors noted, however, that the observed temporal association does not allow causal attributions. Nonetheless, the findings raise the possibility of treating insomnia for the prevention of mental disorders.
Dr Miller is Professor in the Department of Psychiatry and Health Behavior, University of Augusta, Augusta, Georgia. He is the head of the schizophrenia section of Psychiatric Times ™. The author reports that he receives research support 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 Affect Disorder. 2011; 135 (1-3): 10-19.
2. Li L, Wu C, Gan Y 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 disorders: a systematic review and meta-analysis. Sleep Med Rev. 2019; 43: 96-105.