Psychopharmacology
May 1, 2019
Thomas R. Arkell, Nicholas Lintzeris, Richard C. Kevin et al.
177 citations
Both THC-dominant and THC/CBD equivalent cannabis increased lane weaving during simulated driving but had little effect on other driving measures. Impairment on the Digit Symbol Substitution Task, Divided Attention Task, and Paced Auditory Serial Addition Task occurred with both active cannabis types, with worse performance on the latter two tasks after THC/CBD equivalent cannabis. Subjective feelings of being "stoned" and confidence in driving ability did not differ by CBD content. Peak plasma THC concentrations were higher after THC/CBD equivalent cannabis, suggesting a possible pharmacokinetic interaction. Cannabis with equivalent CBD and THC appears no less impairing than THC-dominant cannabis, and CBD may exacerbate THC-induced impairment in some circumstances.
Drug and Alcohol Review
January 1, 2007
Kelly J. Clemens, Iain S. Mcgregor, Glenn E. Hunt et al.
55 citations
The substituted amphetamines MDMA (Ecstasy) and methamphetamine (METH, ice, speed) are increasingly popular among party-drug users. Human studies of their acute and long-term adverse effects are often ambiguous due to confounding factors. Animal models show that intravenous METH is a potent reinforcer, while MDMA enhances social behavior. Brief exposure to either drug can cause long-term reductions in dopamine, serotonin, and noradrenaline in the brain and alter receptor and transporter proteins, though whether this reflects neurotoxicity remains unclear, especially for MDMA. Lasting changes in social behavior, anxiety, depressive symptoms, and memory have been observed in rats, matching some human findings. MDMA/METH combinations may produce greater adverse effects than either drug alone, a concern given that party drug users may frequently encounter this combination.
Social Neuroscience
June 21, 2008
Murray R. Thompson, Glenn E. Hunt, Iain S. Mcgregor
48 citations
MDMA (Ecstasy) produces feelings of love and closeness in humans and prosocial effects in animals. In male Wistar rats, a moderate dose (5 mg/kg) increased social interaction, specifically general investigation of other rats while decreasing anogenital sniffing. Analysis of neural activation across 39 brain regions showed that MDMA given in a social context caused considerably greater brain activation than the same dose given to solitary rats. Six brain regions—including the caudate-putamen, medial preoptic area, paraventricular thalamic nucleus, central amygdala, ventromedial hypothalamic nucleus, and medial amygdala—showed augmented activation in the social-MDMA group. The nucleus accumbens, ventral tegmental area, and periaqueductal grey were activated only when MDMA was combined with social interaction. These findings suggest MDMA modulates neural circuits regulating affiliative behavior, possibly via oxytocin.
Addiction Biology
December 22, 2021
Thomas R. Arkell, Richard C. Kevin, Frederick Vinckenbosch et al.
45 citations
Males and females show few differences in their acute responses to a moderate dose of vaporized cannabis containing 13.75 mg THC, with or without 13.75 mg CBD. After controlling for body mass index and plasma THC concentrations, males performed better on a divided attention task and had higher peak plasma levels of a THC metabolite (11-COOH-THC), but no sex differences appeared in subjective drug effects, cardiovascular measures, or plasma concentrations of THC, CBD, or other metabolites. The findings suggest an absence of systematic sex differences at this dose, though differences might emerge with higher THC doses or other routes of administration.
Psychopharmacology
October 13, 2022
Nadia R. P. W. Hutten, Thomas R. Arkell, Frederick Vinckenbosch et al.
36 citations
Vaporized cannabis containing both THC and cannabidiol (CBD) produces less anxiety than THC alone, but this effect depends on a person's baseline anxiety level. In a placebo-controlled trial with 26 healthy recreational cannabis users, THC-dominant cannabis (13.75 mg THC) and THC/CBD-equivalent cannabis (13.75 mg each) both increased self-rated state anxiety compared to placebo, though the combination caused significantly less anxiety than THC alone. When baseline anxiety was low, CBD completely counteracted THC-induced anxiety; when baseline anxiety was high, CBD did not counteract it. Trait anxiety did not influence the results, and objective measures of attention bias showed no effects.
OBM Neurobiology
June 24, 2021
Sarah-Catherine Rodan, Phillip Aouad, Iain S. Mcgregor et al.
10 citations
Anorexia nervosa (AN) has high mortality and treatment costs, and cognitive behavioural therapy (CBT) achieves remission in at most 50% of adults. Drop-out and relapse rates are high, and no approved pharmacological treatments exist. Over the past two decades, research into classic psychedelics (LSD, 5-MeO-DMT, DMT, and psilocybin) shows that one or two exposures can produce lasting reductions in anxiety and depression, which are the most common co-morbid psychiatric symptoms in AN. The authors suggest that classic psychedelics, especially psilocybin, may normalize dysfunctional neurobiological systems in AN and offer a novel intervention, particularly for treatment-resistant patients.
JAMA Network Open
July 1, 2025
Sarah-Catherine Rodan, Sarah Maguire, Noah Meez et al.
5 citations
In a large international survey of over 6,600 adults with eating disorders or disordered eating, cannabis and psychedelics were rated as most helpful for improving eating disorder symptoms, while prescription antidepressants were seen as beneficial for overall mental health but not for eating disorder symptoms, except for fluoxetine in bulimia nervosa and lisdexamfetamine in binge-eating disorder. Alcohol, nicotine, and tobacco were rated as most harmful. The findings suggest that cannabis and psychedelics may alleviate eating disorder symptoms, supporting further research into these substances as potential treatments.
Journal of Eating Disorders
July 24, 2025
Sarah-Catherine Rodan, Noah Meez, Sophie Lloyd-Hurwitz et al.
2 citations
Among adults with eating disorders, about one in three reported having used a psychedelic drug at some point, and one in five had used one in the past year. Users tended to be younger, less likely to take prescription drugs or be hospitalized for their eating disorder, and more likely to use other non-prescription drugs and to have ADHD, PTSD, ASD, or substance misuse. Those with anorexia nervosa were less likely to report psychedelic use, while those with an undiagnosed eating disorder were more likely. Qualitative comments described profound transformation, increased connectedness, and new insights into illness, though a few reported bad trips or worsened symptoms. The findings suggest psychedelics may hold promise for this population and warrant clinical trials.