Introduction/Aims: 'Hidden’ symptoms, or subtle cognitive deficits and long-term changes in mood, have been
linked to the recreational use of 3, 4-methylenedioxymethamphetamine/MDMA, and are notionally present in non-heavy
polydrug users. This study assessed the cognitive functioning and mood profiles of clinically diagnosed drug dependents
who had never consumed MDMA, recreational drug users that had previously consumed MDMA, with both groups
having not consumed illicit drugs for 6-months, and a control group with limited illicit drug use and no MDMA usage in
Methods: Cognitive functioning was assessed using the Cognitive Drug Research computerised cognitive assessment
system and participants completed the Profile of Mood States and Beck Depression Inventory to assess their current mood
Results: Participants in the clinically diagnosed drug dependent group scored significantly worse on the ‘Quality of
Working Memory’ cognitive factor score than both the MDMA and control group (F (2, 33) = 5.75, p = 0.007). The
control and clinical groups also differed on depression scores (U  = 13.00, p = 0.016) and Tension/Anxiety scores (U
 = 16.00, p = 0.034), with the clinical group scoring significantly higher in both cases. The MDMA group did not
differ from the control group on the measures of cognition or mood.
Discussion/Conclusions: These results suggest that despite a 6-month prolonged abstinence the cognitive deficits
ostensibly caused by ‘heavy’ usage or the dependence on or abuse of illicit drugs are not reversed by abstinence.