Associations of common mental disorder severity with treatment contact and treatment intensity, and its changes over twelve years.

Purpose: To guide formal healthcare resource allocation for common mental disorders (CMDs), this study updates and expands earlier findings on the associations of CMD severity with treatment contact and intensity.

Methods: Baseline data (2019-2022) of NEMESIS-3, a prospective study of a representative cohort of Dutch adults (18-75 years), were used. Severity of 12-month CMDs was assessed with the CIDI 3.0. Using multivariate analyses, its associations with 12-month treatment contact and intensity for emotional/substance-use problems were examined, both for general medical care (GMC) only and mental health care (MHC). Changes over time were identified by making comparisons with baseline data (2007-2009) of NEMESIS-2.

Results: Persons with severe CMDs were more likely to have made contact with GMC only or MHC compared to persons without CMDs. Between 2007-2009 and 2019-2022 there was a greater increase in the contact rate with GMC only for moderate cases compared to persons without CMDs, while the increasing contact rate with MHC did not vary by CMD severity. Both among users of GMC only and MHC, receiving high-intensity treatment was more likely among severe cases compared to persons without CMDs. Between 2007-2009 and 2019-2022 there was a greater increase in the rate of high-intensity treatment for severe cases using GMC only, while results tentatively indicate that this rate declined among severe cases using MHC.

Conclusion: Evidence was found that treatment of CMDs in GMC has been strengthened in the past twelve years. No indications were found that allocation of MHC resources to severe cases has improved.