LONG TERM EFFECTS OF MDMA ADMINISTRATION IN RATS DURING EARLY AND LATE ADOLESCENCE A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Science in Psychology by Olga Kolyaduke

Drug use and abuse for recreational purposes is a common phenomenon, with club drugs such as MDMA (3,4-methylendioxymethamphetamine) being popular for its energetic and euphoric effects – recreating an artificial feeling of “Ecstasy”. Although use of the drug itself has remained relatively constant over the years, the population among which it is popular has been shifting toward younger users, with MDMA use among adolescents becoming more prominent. However research on the effects that MDMA has on the developing adolescent brain has been limited. The current study focuses on the long term effects in rats following chronic MDMA exposure during either early or late adolescence. In adulthood, the rats‟ memory, activity and emotional reactivity were assessed through frequency of ambulation, grooming, rearing, defecation, and corner or center occupancy of an open-field, novel object-recognition in the open-field, emergence from a dark chamber into a bright area, and recognition of the changed arm of the Y-maze. The results showed that there were significant long-term effects resulting in increased anxiety for rats treated with MDMA during late adolescence only. This increase of emotional reactivity was indicated through decreased ambulation on the open-field measures, decreased movement between the dark and light chambers, and decreased entries of both arms of the Y-maze. Sex of the animal was also found to differentiate MDMA effects, with females showing a greater increase in anxiety. Measures regarding spatial and working memory were not significant. Overall, the results suggest that animals are more susceptible to long-term effects following MDMA administration in late, but not early adolescence. Furthermore, memory appears to remain unaffected regardless of the age of administration, and only anxiety levels were affected by the drug.