Rosa Hoshi

Empathy and aggression: two faces of ecstasy? A study of interpretative cognitive bias and mood change in ecstasy users.

RationaleAs central 5-hydroxytryptamine (5-HT) is attenuated for a period following a single dose of MDMA (“ecstasy”) and low 5-HT is associated with aggression, then MDMA users may be more aggressive in the days following an acute dose of the drug.ObjectiveThis study therefore aimed to determine if acute use of MDMA is associated with aggression 4 and 7 days later.MethodsTwenty-nine MDMA users and 32 controls were compared on self-rated aggression and depression on the night of drug use (day 0), 4 and 7 days later. On day 4, participants performed an interpretative bias task in which they processed ambiguous sentences that could be interpreted in either an aggressive or neutral way (e.g. “The painter drew the knife”).ResultsMDMA users had faster response times in completing ambiguous aggressive sentences than neutral sentences; controls showed the opposite pattern of performance. In a subsequent recognition task, MDMA users were more confident in judging, and responded faster to, aggressive than neutral sentences; controls again showed the opposite pattern of effects. The level of aggressive interpretative bias positively correlated with extent of MDMA use. Midweek, MDMA users had higher self-rated aggression and depression scores than controls; on day 7, scores of both groups were similar.ConclusionsMDMA users display a cognitive bias towards interpreting ambiguous information in an aggressive way a few days after taking the drug. Self-rated mid-week low mood and mid-week aggression do not persist 7 days after use of the drug. This pattern of results is consistent both with the acute and residual effects of MDMA on central 5-HT and with the notion that 5-HT plays a role in modulating human aggression.

An investigation into the sub-acute effects of ecstasy on aggressive interpretative bias and aggressive mood – are there gender differences?

The lowering of serotonin for a period following MDMA use could account for the increases in both self-rated and objective measures of aggression previously found in ecstasy users several days after taking the drug. There is some evidence of gender differences in the acute, sub-acute and long-term effects of MDMA use, and given that gender differences have been found in aggression, it is possible that men may experience more aggression mid-week than women. The aim of this study was to attempt to replicate .ndings showing increased bias towards aggressive material in ecstasy users several days after using the drug. In addition, to investigate possible gender differences in mid-week aggression. A total of 46 participants were tested: 19 ecstasy users and 27 controls were compared on the night of drug use and 4 days later. On day 4, a task designed to tap cognitive bias toward material with aggressive content was administered. Participants were required to process sentences that could be interpreted as either aggressive or neutral and subsequently remember them in a recognition test. This data set was then combined with the data from Curran et al.s (2004) study that employed exactly the same procedure. Thus, the data from 107 participants was analysed to investigate gender differences. Ecstasy users recognized more aggressive sentences than controls and tended to react slower to neutral sentences than controls. Ecstasy users also rated themselves as being more aggressive and depressed than controls on day 4. No gender differences were found on any measure of aggression in the combined data set. Both male and female ecstasy users show a bias toward interpretation of ambiguous material in an aggressive manner when compared to controls 4 days after ecstasy use.

Persistent Nigrostriatal Dopaminergic Abnormalities in Ex-Users of MDMA (‘Ecstasy'): An 18F-Dopa PET Study

Ecstasy (±3,4-methylenedioxymethamphetamine, MDMA) is a popular recreational drug with known serotonergic neurotoxicity. Its long-term effects on dopaminergic function are less certain. Studying the long-term effects of ecstasy is often confounded by concomitant polydrug use and the short duration of abstinence. We used 18F-dopa positron emission tomography (PET) to investigate the long-term effects of ecstasy on nigrostriatal dopaminergic function in a group of male ex-recreational users of ecstasy who had been abstinent for a mean of 3.22 years. We studied 14 ex-ecstasy users (EEs), 14 polydrug-using controls (PCs) (matched to the ex-users for other recreational drug use), and 12 drug-naive controls (DCs). Each participant underwent one 18F-dopa PET, cognitive assessments, and hair and urinary analyses to corroborate drug-use history. The putamen 18F-dopa uptake of EEs was 9% higher than that of DCs (p=0.021). The putamen uptake rate of PCs fell between the other two groups, suggesting that the hyperdopaminergic state in EEs may be due to the combined effects of ecstasy and polydrug use. There was no relationship between the amount of ecstasy used and striatal 18F-dopa uptake. Increased putaminal 18F-dopa uptake in EEs after an abstinence of >3 years (mean) suggests that the effects are long lasting. Our findings suggest potential long-term effects of ecstasy use, in conjunction with other recreational drugs, on nigrostriatal dopaminergic functions. Further longitudinal studies are required to elucidate the significance of these findings as they may have important public health implications.

Ecstasy (MDMA) Does Not Have Long-Term Effects on Aggressive Interpretative Bias: A Study Comparing Current and Ex-Ecstasy Users With Polydrug and Drug-Naive Controls

+/-3, 4-methylenedioxymethamphetamine (MDMA or ecstasy) remains a widely used recreational drug, which, in animals, can produce long-lasting changes to the brains serotonergic system. As serotonin has been implicated in human aggression, it is possible that ecstasy users are at risk of increased aggression even after prolonged abstention from the drug. The objective of this study was to indirectly assess aggression in current and abstinent ecstasy users using an information-processing paradigm that measures cognitive bias toward material with aggressive content. The task employed has previously shown increased aggressive bias 3-4 days after ecstasy use. An interpretative bias task was administered to 105 male participants: 26 ex-ecstasy users, 25 current ecstasy users, 29 polydrug using controls, and 25 drug-naive controls. Accuracy and response times to process and recognize ambiguous sentences were tested. There were no group differences in aggressive interpretative bias. All 4 groups processed neutral sentences faster than aggressive sentences and were subsequently faster and more confident in recognizing neutral compared with aggressive sentences. Further, self-ratings of aggression also showed no group differences, even though self-rated impulsivity was significantly higher in current ecstasy users than in drug-naive controls. The findings that all groups were biased toward neutral and away from aggressive interpretations of ambiguous sentences add to the existing body of knowledge in suggesting that increased aggression found in ecstasy users a few days after taking the drug is a transient phenomenon and not a long-term, persisting effect.