The drug purity discounting task: Ecstasy use likelihood is reduced by probabilistic impurity according to harmfulness of adulterants

• Published in: Drug and alcohol dependence 2020-03, Vol.208, p.107772-107772, Article 107772
• Main Authors: Dolan, Sean B., Johnson, Matthew W.
• Format: Article
• Language: English
• Subjects: Adult; Adulterants; Affect - physiology; Behavioral economics; Delay Discounting - physiology; Demand; Drug abuse; Drug checking; Drug Contamination; Economics, Behavioral - trends; Ecstasy; Ecstasy drug; Female; Frame analysis; Hallucinogens - standards; Health behavior; Health information; Humans; Illicit Drugs - standards; Impurities; Male; MDMA; N-Methyl-3,4-methylenedioxyamphetamine - standards; Pharmacology; Probabilistic methods; Probability; Probability discounting; Public health; Purity; Statistical analysis; Surveys and Questionnaires
• ISSN: 0376-8716; 1879-0046; 1879-0046
• DOI: 10.1016/j.drugalcdep.2019.107772

•Ecstasy use likelihood decreases as perceived sample impurity increases.•Framing conditions about inert adulterants increased impure Ecstasy use likelihood.•Framing for unspecified or potentially-harmful adulterants decreased use likelihood.•Hypothetical Ecstasy purchasing was not influenced by framing conditions.•Inelastic purchasing was associated with greater impure Ecstasy use likelihood. Ecstasy typically contains adulterants in addition to, or in lieu of, MDMA which may pose a greater risk to users than MDMA itself. The current study aimed to evaluate the effectiveness of adulterant-related informational prompts in reducing Ecstasy use using a novel probability discounting task. An online sample of past-month Ecstasy users (N = 278) were randomized to one of four different framing prompt conditions: no prompt; a prompt describing MDMA’s effects; a prompt describing adulterants as inert “filler”; or a prompt describing adulterants as pharmacologically-active, potentially-harmful compounds. Each prompt contained general, potential public-health information that was not specifically related to subsequent behavioral tasks. All participants then completed an identical Drug Purity Discounting Task, in which they indicated the likelihood of using a sample of Ecstasy across different probabilities of the sample being impure, and then completed a hypothetical Ecstasy purchasing task. Likelihood of Ecstasy use decreased as impurity probability increased across conditions. Ecstasy use likelihood was highest in the “inert” prompt condition, whereas pharmacologically-active adulterant or adulterant-nonspecific prompts resulted in comparably low likelihood of use. Ecstasy-use likelihood did not differ among conditions when the likelihood of sample impurity was 0. Ecstasy purchasing did not differ among groups. Inelastic purchasing was associated with greater likelihood of using potentially-impure Ecstasy. Altogether, these data highlight the necessity of education regarding pharmacologically-active, rather than inert, adulterants in Ecstasy, and suggest that increased access to drug checking kits and services may mitigate some of the harms associated with Ecstasy use.