Depression and anxiety among chronic pain patients receiving prescription opioids and medical marijuana.

BACKGROUND: High rates of depression and anxiety have been consistently reported among patients suffering from chronic pain. Prescription opioids are one of the most common modalities for pharmacological treatment of pain, however in recent years medical marijuana(MM) has been increasingly used for pain control in the US and in several countries worldwide. The aim of this study was to compare levels of depression and anxiety among pain patients receiving prescription opioids and MM.

METHODS: Participants were patients suffering from chronic pain treated with prescription opioids (OP,N=474), MM (N=329) or both (OPMM,N=77). Depression and anxiety were assessed using the depression module of the Patient Health Questionnaire (PHQ-9) and the Generalized Anxiety Disorder scale (GAD-7).

RESULTS: Prevalence of depression among patients in the OP, MM and OPMM groups was 57.1%, 22.3% and 51.4%, respectively and rates of anxiety were 48.4%, 21.5% and 38.7%, respectively. After controlling for confounders, patients in the OP group were significantly more likely to screen positive for depression (Adjusted Odds Ratio(AOR)=6.18;95%CI=4.12-9.338) and anxiety(AOR=4.12;CI=3.84-5.71)) compared to those in the MM group. Individuals in the OPMM group were more prone for depression (AOR for depression=3.34;CI=1.52-7.34)) compared to those in the MM group.

LIMITATIONS: Cross-sectional study, restricting inference of causality.

CONCLUSIONS: Levels of depression and anxiety are higher among chronic pain patients receiving prescription opioids compared to those receiving MM. Findings should be taken into consideration when deciding on the most appropriate treatment modality for chronic pain, particularly among those at risk for depression and anxiety.