Health service use among individuals with depression and psychological distress: a population-based cohort study in Ontario, Canada

Objectives — Relatively little is known about how health-care utilization differs among individuals with psychological distress compared to those with major depressive disorder (MDD).

Methods — Ontario participants of the Canadian Community Health Survey Cycle 1.2 (2002) were linked to health administrative data to follow their health-care utilization patterns for up to 15 years. Based on their survey responses, we classified individuals hierarchically into Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria MDD, psychological distress (Kessler-6: 8 to 24), or an unexposed group with neither condition. We compared the rates of outpatient and acute care mental and nonmental health-related visits across the 3 groups over time using Poisson regression.

Results — Among the 668 individuals with MDD, 430 with psychological distress, and 9,089 in the unexposed group, individuals with MDD and psychological distress had higher rates of health-care utilization than the unexposed overall and across time. The rates of psychiatrist visits for the MDD group were significantly higher than the other groups initially but declined over the follow-up. Conversely, the rates of psychiatrist visits among the psychological distress group increased over time and converged with that of the MDD group by the end of follow-up (rate ratioMDD vs. psychological distress at 1 year: 4.20 [1.97 to 11.40]; at 15 years: 1.53 [0.54 to 4.08]). Acute care visits were similar between the MDD and psychological distress groups at all time points.

Conclusions — Individuals with psychological distress required mental healthcare rivalling that of individuals with MDD over time, suggesting that even a cross-sectional assessment of significant psychological distress is a serious clinical concern.