Misuse of psychoactive medicines and its harmful consequences in Portugal
Background: Psychoactive medicines (PMed) provide clinically meaningful relief in many psychiatric disorders. However, they are also a unique group of medicines to monitor due to their misuse risks. The aim of this study was to analyse morbimortality consequences of PMed misuse.
Methods: Retrospective multi-source cross-sectional study on PMed misuse morbimortality consequences and PMed sales data. All violent deaths, emergency department (ED) admissions, intentional poisoning calls, adverse drug reactions (ADR) reports and sales data involving prescription opioids (PO), sedatives (including benzodiazepines/z-drugs (BZDR), antidepressants (AD), anticonvulsants and psychostimulants, occurring in Portugal between 2014 and 2018, were included. We estimated prevalences, population- and exposure-based rates of the outcomes of interest: PMed-contributing deaths and ED admissions, and serious PMed misuse poisoning calls and ADRs. To study the association of the outcomes with exposures we calculated relative risks, and with sales data we computed Spearman correlation coefficients.
Results: Women prevailed in all outcomes of interest. PMed misuse-caused ED admissions had lower effective hospitalisation rates with shorter duration, lower severity and lower mortality risks (p<0.001) than other admissions with PMed misuse as secondary diagnosis. Nevertheless, intentional PMed exposures involving substance combinations, BZDR, AD or PO were mostly serious, with 70.2%, 65.6%, 67.1% and 67.4% of these intentional PMed exposures referring to serious poisonings. Correlation with exposure data was positive for all outcomes, stronger for serious poisoning calls (Spearman r=0.89, p<0.0001). Most (94.6%) of PMed contributing deaths involved substance combinations (PMeds, PMed(s) and/or alcohol and/or illicit drugs), vs. 67.9% of deaths without PMed contribution (p<0.001). Substance combinations and AD increased the risk of PMed being the cause of death [RR=8.01 (95% CI 4.10-15.7) and RR=3.20 (2.28-4.49)] and of ED admission [RR=1.58 (4.11.52-1.64) and RR=1.86 (1.80-1.93)], as well as of the call being a serious poisoning [RR=1.12 (1.10-1.14) and RR=1.04 (1.02-1.05)]. Alprazolam and sertraline, the most consumed PMed, had the highest population rates; however, the patient-based rate ranking is led by morphine and tricyclic antidepressants, resulting from their lower extent of use. No other opioid is present in the higher positions of this ranking, which taken together with sales data pointing to low levels of prescription opioid use, provides some reassurance on a possible insidious prescription opioid crisis in our country.
Conclusions: BZDR and AD are the main groups implicated in PMed-related morbimortality, with AD and substance combinations increasing the risk of psychoactive medicines contribution and seriousness of morbimortality events, confirming extensive evidence on the role of substance combinations in the increase of medicine-related harms.
