What happens when people use both MDMA and cannabis together | Research

The takeaway

A review of 23 studies found co-use of MDMA and cannabis appeared to produce additive negative effects on memory, mediated by interactions between cannabinoid, serotonin, and dopamine systems.

Read this if you want to understand the cognitive risks of using MDMA and cannabis together.

23 articles reviewed on a very common but understudied drug combination

What the researchers found

This review examined 23 articles on the combined effects of MDMA (ecstasy) and cannabis. Human retrospective studies pointed to additive negative effects on different types of memory in long-term co-users, with cannabis-independent decreases in learning and decision-making among MDMA users.

Animal studies showed that acute co-administration of MDMA and cannabinoid agents affected body temperature, conditioned reinforcement, and presumed neurotoxicity. The neural mechanisms involved interactions between the CB1 receptor and serotonergic and dopaminergic systems in the prefrontal cortex, nucleus accumbens, and hippocampus.

The review noted that despite MDMA-cannabis co-use being very common among recreational drug users, surprisingly few studies had specifically examined the combination.

Why it matters

MDMA and cannabis are frequently used together in recreational settings, but most drug research examines each substance in isolation. Understanding their interaction helps predict risks for the large population of co-users.

The numbers in context

23 articles reviewed (2002-2010). Brain regions involved: prefrontal cortex, nucleus accumbens, hippocampus. Neurotransmitter systems: CB1, serotonin, dopamine.

How the study worked

Mini-review of 23 articles published between 2002 and 2010 specifically examining combined MDMA and cannabis/cannabinoid effects. Included human retrospective cognitive studies and animal behavioral and neurobiological experiments.

What this study cannot tell us

Most human studies were retrospective, meaning they could not prove the drugs caused the observed cognitive deficits. Polydrug use makes it difficult to isolate specific drug combination effects. Few studies examined chronic co-administration in animals.

How to read the evidence

Mini-review of a small literature with mostly retrospective human studies and limited animal experiments. Identifies knowledge gaps more than it resolves them.

When this study was published

Published in 2011. Research on polydrug interactions has expanded since, though MDMA-cannabis co-use remains understudied.

The bigger picture

The finding that cognitive effects were additive rather than synergistic is important for harm reduction messaging. Co-users face compounded memory impairment, and the CB1-serotonin-dopamine interaction may have implications for understanding long-term neurotoxicity.

Questions still open

Does cannabis use worsen MDMA neurotoxicity or provide some protection? Are the memory effects reversible with abstinence from both drugs? What specific CB1-serotonin interactions drive the combined effects?

Common questions

Does mixing MDMA and cannabis make memory problems worse?

The reviewed studies suggested additive negative effects on memory, meaning the combined impact appeared to be the sum of each drug's individual effects rather than something exponentially worse. Both drugs independently affect memory through overlapping brain regions.

Why is this combination so common?

Many recreational drug users consume multiple substances. MDMA and cannabis are among the most popular recreational drugs, and users often combine them at social events or festivals. Despite high co-use rates, few studies have specifically examined the interaction.

Read the original research

MDMA & cannabis: a mini-review of cognitive, behavioral, and neurobiological effects of co-consumption.

Current drug abuse reviews, 4(2), 81-6

View on PubMed ↗

Citation

Schulz, Sybille. (2011). MDMA & cannabis: a mini-review of cognitive, behavioral, and neurobiological effects of co-consumption.. Current drug abuse reviews, 4(2), 81-6.