Psychiatric risk factors for chronic high-dose opioid prescribing: register-based cohort study.

Background: Chronic high-dose (CHD) prescription opioid use is a major public health concern. Although CHD opioid use has been associated with psychiatric disorders, the causality could go both ways. Some studies have already linked psychiatric disorders to an increased risk of transitioning to chronic opioid use, and longitudinal data identifying psychiatric disorders as predictors of CHD opioid use could shed further light on this issue.

Aims: To prospectively examine the relationship between the presence of a psychiatric disorder and subsequent development of CHD opioid use in primary care patients newly receiving opioids.

Method: Data were included from 137 778 primary care patients in The Netherlands. Cox regression modelling was used to examine the association between psychiatric disorders prior to a new opioid prescription and subsequent CHD opioid use (≥90 days; ≥50 mg/day oral morphine equivalents) in the subsequent 2 years.

Results: Of all patients receiving a new opioid prescription, 2.0% developed CHD opioid use. A psychiatric disorder before the start of an opioid prescription increased the risk of CHD opioid use (adjusted hazard ratio HR = 1.74; 95% CI 1.62-1.88), specifically psychotic disorders, substance use disorders, neurocognitive disorders and multiple co-occurring psychiatric episodes. Similarly, pharmacotherapy for psychosis, substance use disorders and mood and/or anxiety disorders increased the risk of CHD opioid use. Psychiatric polypharmacy conferred the greatest risk of developing CHD opioid use.

Conclusions: Psychiatric disorders increase the risk of developing CHD opioid use in patients newly receiving prescription opioids. To reduce the public health burden of CHD opioid use, careful monitoring and optimal treatment of psychiatric conditions are advised when opioid therapy is initiated.