Sociodemographic, psychiatric, and personality correlates of non-prescribed use of amphetamine medications for academic performance among medical students.

Abstract

Use of psychostimulants without a medical indication to supposedly improve academic performance is common among medical students, but its correlates remain poorly understood. In this cross-sectional study (Plataforma Brasil ethical approval 52982815.9.0000.5636), we explored sociodemographic, psychiatric, and personality factors associated with this phenomenon. Students from all semesters of two universities (A, public, and B, private) in the metropolitan area of Florianópolis (state of Santa Catarina, Brazil) were invited, at the start or the end of classes, to answer an anonymous, self-report questionnaire about methylphenidate or lisdexamfetamine use patterns, gender, living situation, household monthly income per capita, and last-month cannabis use, as well as complete the Alcohol Use Disorders Identification Test Consumption (AUDIT-C), 4-item Patient Health Questionnaire (PHQ-4), Adult Attention-Deficit/Hyperactivity Disorder (ADHD) Self-Report Scale (ASRS), and Big Five Inventory (BFI) instruments. Of 707 students enrolled, 698 (98.7%) completed the questions about methylphenidate or lisdexamfetamine use. Of these, 81.8% had never used these medications, 7.0% had ever used them with a medical prescription, and 11.2% had ever used them without a prescription. Students with prescribed use were excluded due to likely ADHD. Of those with non-prescribed use, 28.2% (n=22) used in the past month (median [interquartile interval], 2.0 [1.0-6.3] days of use in this period) and 71.8% (n=56) had done so more than 1 month before (2.0 [0.0-4.0] days of use in the past year). Motivations for non-prescribed use (more than one could be endorsed) were to study longer (84.6%), increase concentration (46.2%), stay awake (28.2%), experiment (15.4%), and party (10.3%). First, we performed preliminary analyses (MannWhitney or chi-square tests) comparing students with non-prescribed use for academic performance (to study longer, increase concentration, or stay awake; n=71, or 10.2% of the sample) to students without use (n=571). Non-prescribed use for academic performance was significantly associated (p o 0.05) with studying in University B, older age, last-month cannabis use, higher AUDIT-C and lower BFI conscientiousness scores, and screening positive in the ASRS (score of 24 or greater in part A or B). We then simultaneously entered these variables into a multiple logistic regression model to define independent significant associations (Table 1). Assumptions: numerical variables met the logit linearity assumption in the Box-Tidwell test (p 4 0.05); no numerical variables showed a tolerance o 0.1 or a variance inflation factor 4 5; no cases had a Cook’s distance 4 1; 15 cases had an absolute standardized residual 4 3; an analysis excluding these cases improved model fit (Hosmer-Lemeshow p = 0.74; Nagelkerke’s R = 0.35; c = 0.88), but did not change significance patterns. Although many studies have addressed non-prescribed use of psychostimulant medication among medical students, ours was novel in its broad exploration of factors independently associated with this phenomenon. For example, very few studies in university students took personality measures into account. Prevalence of nonprescribed use was similar or somewhat lower in our sample than in other studies, and most students reported sporadic use. The associations with cannabis