OPEN Foundation

M. Walter

Interaction of Sex and Age on the Dissociative Effects of Ketamine Action in Young Healthy Participants.


Ketamine is a drug that reduces depressive and elicits schizophrenia-like symptoms in humans. However, it is largely unexplored whether women and men differ with respect to ketamine-action and whether age contributes to drug-effects. In this study we assessed dissociative symptoms via the Clinician Administered Dissociative States Scale (CADSS) in a total of 69 healthy subjects aged between 18 and 30 years (early adulthood) after ketamine or placebo infusion. Dissociative symptoms were generally increased only in the ketamine group post-infusion. Specifically, within the ketamine group, men reported significantly more depersonalization and amnestic symptoms than women. Furthermore, with rising age only men were less affected overall with respect to dissociative symptoms. This suggests a sex-specific protective effect of higher age which may be due to delayed brain maturation in men compared to women. We conclude that it is crucial to include sex and age in studies of drug effects in general and of ketamine-action in specific to tailor more efficient psychiatric treatments. Clinical Trial Registration: EU Clinical Trials Register (EudraCT), trial number: 2010-023414-31.
Derntl, B., Hornung, J., Sen, Z. D., Colic, L., Li, M., & Walter, M. (2019). Interaction of sex and age on the dissociative effects of ketamine action in young healthy participants. Frontiers in neuroscience13,
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Neuroimaging in moderate MDMA use: A systematic review


MDMA (“ecstasy”) is widely used as a recreational drug, although there has been some debate about its neurotoxic effects in humans. However, most studies have investigated subjects with heavy use patterns, and the effects of transient MDMA use are unclear. In this review, we therefore focus on subjects with moderate use patterns, in order to assess the evidence for harmful effects. We searched for studies applying neuroimaging techniques in man. Studies were included if they provided at least one group with an average of <50 lifetime episodes of ecstasy use or an average lifetime consumption of <100 ecstasy tablets. All studies published before July 2015 were included. Of the 250 studies identified in the database search, 19 were included.

There is no convincing evidence that moderate MDMA use is associated with structural or functional brain alterations in neuroimaging measures. The lack of significant results was associated with high methodological heterogeneity in terms of dosages and co-consumption of other drugs, low quality of studies and small sample sizes.

Mueller, F., Lenz, C., Steiner, M., Dolder, P. C., Walter, M., Lang, U. E., … & Borgwardt, S. (2016). Neuroimaging in moderate MDMA use: A systematic review. Neuroscience & Biobehavioral Reviews, 62, 21-34.
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11 December - Panel discussion on the Metaphysics of Psychedelic Experiences