Aims: It still remains unclear whether psychopathological abnormalities described in human 3,4-methylenedioxymethamphetamine users (MDMA users) and d-amphetamine users (AMPH users) existed before the beginning of regular use or if they develop with ongoing use.
Objectives: The present study was conducted in order to assess this relationship and to overcome previous methodological shortcomings.
Methods: A longitudinal cohort study in 96 beginning MDMA and d-amphetamine users between 2006 and 2011 with a follow-up duration of 24 months. In order to explore the impact of MDMA and AMPH use on self-reported psychopathology (measured by the Symptom Checklist-90-Revised), mixed models for repeated measures were fitted. In order to examine the impact of previous psychopathology on subsequent use, partial correlation analyses and linear regression analyses were applied.
Results: Over the course of the 2-year follow-up period, 31 subjects used neither MDMA nor AMPH (non-users); 65 subjects used both MDMA and AMPH: 37 subjects used between 1 and 14 tablets of MDMA and 28 subjects used 15 or more tablets of MDMA. Thirty-three subjects used between 1 and 14 g of AMPH, and 32 subjects used 15 g or more. No associations concerning MDMA/AMPH use and development of self-reported psychopathology were found. However, there was a significant relationship between globally increased self-reported psychopathology-particularly psychoticism-at the beginning of the study and subsequent AMPH use.
Conclusions: The data of the present study suggest that a certain psychopathological profile could form a risk factor for later use of amphetamines.