We previously reported that regular recreational intranasal cocaine users exhibit impaired recognition of facial expressions of fear compared to occasional cocaine users and cocaine-naïve controls. The aim of the present study was to re-investigate this phenomenon after controlling for impulsivity, conduct disorder (CD) and anti-social personality disorder (ASPD). We employed a cross-sectional design to compare 31 cocaine-naïve participants, 35 occasional cocaine users and 20 regular recreational cocaine users. An emotional facial expression (EFE) task which comprised a male and a female face expressing six basic emotions morphed to differing degrees of emotional intensity was administered together with questionnaires to assess: CD, ASPD and impulsiveness. ASPD was not a significant covariate for EFE performance but impulsiveness and CD were significant covariates. After treating impulsiveness and CD as covariates we again observed a group difference in fear recognition ability attributable to the particularly impaired performance of regular cocaine users. This suggests that, although elevated impulsiveness and CD before the age of 15 years, may predispose a relative inability to recognize facial expressions of fear in adulthood, subsequent regular recreational use of cocaine represents an additional factor that is specifically associated with a selective deficit in fear recognition.

The aim of this study was to differentiate the subacute from the chronic effects of ecstasy. Regular ecstasy users who subsequently chose to take ecstasy (experimental group: E, N = 16) were compared with regular ecstasy users who opted not to (control group: C, N = 16). Groups were assessed with neuropsychological and psychometric measures at drug-free baseline before ecstasy use and 1 and 4 days after use. Ecstasy users who consumed ecstasy (E) did not differ from those who did not (C) in relation to age, estimated IQ, personality or past substance use, including ecstasy. At baseline, E reported being more energetic, lively and cheerful whereas the day after ecstasy use they reported being more muddled, afraid, sad and dejected than C. However, this was not significant after controlling for sleep deprivation. Mood returned to baseline within 3 days and there were no group differences in Beck depression inventory scores at any of the three testing sessions. There were no subacute effects of ecstasy on working memory, story recall, impulsivity, or decision-making. However, at baseline and the day after use ecstasy users made poorer decisions, and were less sensitive to punishment, in the Somatic marker sensitivity test. These findings suggest that previous reports of marked subacute effects of ecstasy use may have been confounded by chronic polydrug use before use, co-substance use and sleep disturbances after use.