Evaluation of common prescription analgesics and adjuvant analgesics as markers of suicide risk: a longitudinal population-based study in England

Background: Analgesics prescriptions may provide a marker for identifying individuals at higher risk of suicide. In particular, awareness of which analgesics are implicated may help clinicians assess and modify risk. Method: A case-control study in England using the Clinical Practice Research Datalink (for primary care records) linked with hospital and national mortality electronic registries. We included patients aged ≥15 who died by suicide between 2001 and 2019 (N = 14,515), to whom we individually matched 580,159 controls by suicide date and general practice (N = 594,674). Odds ratios (ORs) for suicide, controlled for age and sex, were assessed using conditional logistic regression. Findings: Suicide risks were highest in those prescribed adjuvant analgesics (pregabalin, gabapentin and carbamazepine) (adjusted OR 4.07; 95% confidence intervals CI: 3.62-4.57), followed by those prescribed opioids (adjusted OR 2.01; 95% CI: 1.88-2.15) and those prescribed non-opioid analgesics (adjusted OR 1.48; 95% CI: 1.39-1.58) compared to those not prescribed these medications. By individual analgesic, the highest suicide risks were seen in patients prescribed oxycodone (adjusted OR 6.70; 95% CI: 4.49-9.37); pregabalin (adjusted OR 6.50; 95% CI: 5.41-7.81); morphine (adjusted OR 4.54; 95% CI: 3.73-5.52); and gabapentin (adjusted OR 3.12; 95% CI: 2.59-3.75). Suicide risk increased linearly with the number of analgesic prescriptions in the final year (p < 0.01 based on the likelihood ratio test), and the more different analgesics categories were prescribed in the final year (p < 0.01 based on the likelihood ratio test). Interpretation: Analgesic prescribing was associated with higher suicide risk. This is a particular issue with regard to adjuvant non-opiate analgesics. Funding: There was no funding for this study.