An SSRI blocked most of MDMA's psychological effects in a placebo-controlled study of 16 volunteers
Citalopram pretreatment "markedly reduced" the heightened mood, self-confidence, extroversion and sensory intensification that MDMA produced in healthy volunteers, because MDMA needs the serotonin transporter the SSRI occupies.
Reasonable evidence with real limitations. how we score evidence
Caveat on this rating: Sixteen healthy volunteers, single doses, intravenous citalopram rather than chronic oral SSRI treatment; a person on months of an oral SSRI may respond differently. Whether the cardiovascular effects of MDMA were also reduced is not stated in the abstract and is not claimed here.
"Will my antidepressant stop ecstasy from working" has a measured answer from a Swiss laboratory, and it also explains why the combination is not simply safe.
Significant findings
Liechti and colleagues (Neuropsychopharmacology, 2000) gave MDMA 1.5 mg per kilogram by mouth to 16 healthy volunteers in a double-blind, placebo-controlled study, with or without pretreatment with citalopram 40 mg intravenously.
"MDMA produced an emotional state with heightened mood, increased self-confidence and extroversion, moderate derealization, and an intensification of sensory perception. Most of these effects were markedly reduced by citalopram."
The mechanism, from the abstract: "The effect of MDMA on 5-HT release can be blocked by 5-HT uptake inhibitors such as citalopram, suggesting that MDMA interacts with the 5-HT uptake site." The finding "suggests that the psychological effects of MDMA are mediated via action at the 5-HT uptake site to increase 5-HT release through the carrier".
Worth asking
Two consequences follow, in opposite directions. The first is that a person on an SSRI who takes MDMA and feels little may take more, and the dose that goes up is the dose whose heart and temperature effects were not blocked. The second is that MDMA and an SSRI both raise serotonin, and every SSRI label lists amphetamines among the drugs that raise serotonin syndrome risk. The Vuori 2003 row in this wave is what happened when MDMA met an MAOI antidepressant. A person on an antidepressant who is going to use MDMA anyway should know that "it did nothing" is not the same as "it was safe".
Source
Acute psychological effects of 3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy") are attenuated by the serotonin uptake inhibitor citalopram — Liechti ME, Baumann C, Gamma A, Vollenweider FX (2000)
Reputable peer-reviewed journal
Read the source: https://doi.org/10.1016/S0893-133X(99)00148-7
DOI: 10.1016/S0893-133X(99)00148-7
How this was scored
- Study design
- Randomised controlled trial
- Funding
- Funding not disclosed
- Published in
- Reputable peer-reviewed journal
- Sample size
- 16
- Preregistered
- not recorded
- Conflicts disclosed
- not recorded
- Independent of proponent
- not recorded
- Retracted
- No
Read the full scoring rubric, including what it can't tell you.
Published September 21, 2026.
Questions
How strong is the evidence behind this?
veisund rates this source "moderate evidence". Reasonable evidence with real limitations. It scores 55 out of 100 on our published rubric. One caveat travels with that badge: Sixteen healthy volunteers, single doses, intravenous citalopram rather than chronic oral SSRI treatment; a person on months of an oral SSRI may respond differently. Whether the cardiovascular effects of MDMA were also reduced is not stated in the abstract and is not claimed here. The score is calculated from recorded facts about the source — study design, funding, publication venue, sample size, preregistration — not typed in by an editor.
What is the source for this?
Acute psychological effects of 3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy") are attenuated by the serotonin uptake inhibitor citalopram — Liechti ME, Baumann C, Gamma A, Vollenweider FX (2000). Published in: Reputable peer-reviewed journal. DOI: 10.1016/S0893-133X(99)00148-7. The full source is linked on this page so you can read it yourself.
Who paid for this research, and does that matter?
Study design: Randomised controlled trial. Funding: Funding not disclosed. Independence from the proponent is not recorded. Industry sponsorship is one of the most reliably measured biases in medicine, which is why funding carries real weight in the score rather than sitting in a footnote.
Is this medical advice?
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.