Insomnia—A risk factor for mental disorders

Longitudinal studies observed that individuals suffering from insomnia disorder have a higher vulnerability to develop symptoms of psychopathology compared with good sleepers. Particularly, insomnia disorder has been associated with an increased risk for depression. Previous studies indicate relatively stable effects; however, replication is needed as the last meta-analysis on the topic has been published 4 years ago. We conducted a replication of a previous systematic review and meta-analysis evaluating the longitudinal association between insomnia disorder and psychopathology, including original works published between 2018 and 2022. Literature search was conducted from April 2018 to August 2022 using key words identifying longitudinal studies that evaluate individuals with insomnia disorder compared with good sleepers at baseline, and the onset of all possible mental disorders at long-term follow-up. Only one work was added to the previous sample of studies published in 2019 looking at the longitudinal association between insomnia disorder and depression. Meta-analytic results confirmed the previous observation, with an even higher observed effect for the link between insomnia and depression. This again recognizes insomnia disorder as a possible transdiagnostic process in psychopathology, with consequent important clinical implications. Nevertheless, more longitudinal studies are needed evaluating the link between insomnia disorder and mental disorders.