Insomnia symptoms and short sleep duration predict trajectory of mental health symptoms

We evaluated whether insomnia symptoms and short or long sleep duration, alone or in combination, are robustly associated with subsequent trajectory of mental health symptoms.

Participants were 2598 individuals (15 to 94 years of age) with elevated mental health symptoms at baseline (2013-14). Associations of baseline insomnia symptoms and sleep duration with two-year trajectory of mental health were estimated and adjusted for multiple potential confounders. Outcomes included recovery (well at both follow-up timepoints), intermittent symptoms (unwell at one follow-up timepoint), and chronic symptoms (unwell at each follow-up timepoint).

Adjusted for age and sex, baseline insomnia symptoms predicted intermittent (OR 1.43, 95% CI 1.15-1.80) and chronic (OR 2.16, 95% CI 1.77-2.68) trajectories of mental health symptoms. Short sleep duration (<6 h and ≥6 to <7 h) only predicted a chronic trajectory (ORs 1.70-2.06). Associations were attenuated but significant after confounder adjustment. Those who experienced both insomnia and short (<7 h) sleep duration had the greatest risk of chronic mental health symptoms (OR 2.35, 95% CI 1.60-3.45).

A focus on just sleep duration or insomnia symptoms in those with elevated mental health symptoms will not be adequate to address chronicity. Both components of sleep disturbance, and in particular their co-occurrence, should be addressed.