Co-use of cannabis and tobacco in the same occasion: Acute effects. A systematic review.
Jingqi Xu, Adrien Nette, Christina Zakala, Sampson Zhao, Justin Matheson, Christine M Wickens, Sarah Bonato, Patricia Di Ciano
Psychopharmacology October 5, 2026 DOI: 10.1007/s00213-026-07174-w (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Systematic review Randomized Longitudinal Cross-sectional Qualitative Peer reviewed |
|---|---|
| Topics | Cannabis |
| Keywords | Blunts Chasing Co-administration Mulling Sequential co-use Spliffs |
| Key findings | The review reports mixed evidence on same-occasion cannabis and tobacco co-use: three studies found each drug attenuated the other's cognitive effects, while eight found subjective effects no different from either drug alone. Two studies reported tobacco dulled cannabis effects and two that tobacco increased cannabis's stimulant properties. Physiological findings were inconclusive, and the authors call for larger studies. |
Abstract
Cannabis and tobacco are widely used substances with addiction potential, which have opposing effects on cognition and subjective experience and are often co-used in a single occasion. The purpose of this systematic review was to synthesize evidence of the acute effects of same-occasion co-use of cannabis and tobacco. Databases Embase, Medline, CINAHL, PsycINFO, and Web of Science were searched from inception to May 2025. Inclusion criteria were broad. Included studies were peer-reviewed papers, theses, grey literature and abstracts. Designs included randomized controlled trials, laboratory studies, epidemiological studies, qualitative studies, case reports, before-and-after studies, cohort, case-control, cross-sectional, longitudinal, secondary data analysis and naturalistic studies. Papers were screened and selected by two authors and studies were evaluated for quality with the SIGN methodology. In total, 18 studies were included in the present synthesis, and some contained information on multiple outcomes. Five studies examined effects of same-occasion co-use of cannabis and tobacco on cognition; 12 studies evaluated same-occasion co-use on subjective experience; and seven studies evaluated effects on physiological measures. With respect to cognition, three studies found that cannabis and tobacco each attenuated the effects of the other, but the findings were not always consistent. For subjective experience, eight studies reported that the effects of same-occasion co-use of cannabis and tobacco did not differ from the effects of either drug on its own. Two studies of subjective experience found that tobacco dulled the effects of cannabis and two found that tobacco increased the stimulant properties of cannabis. In sum, the evidence for additive effects of cannabis and tobacco is mixed, with some studies reporting that cannabis and tobacco attenuate the effects of the other on cognition. There are inconclusive findings with respect to the combined effects of cannabis and tobacco on subjective effects and physiological outcomes. However, studies are limited and more large-scale studies that investigate the full range of diverse effects of cannabis and tobacco are needed.
Comparable studies
Other systematic reviews and meta-analyses on cannabis, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Effects of cannabis use on outcomes of psychotic disorders: systematic review People with psychotic disorders, as examined in 13 longitudinal studies | 2008 | Systematic review | |
| The Impact of Cannabis Use on Cognitive Functioning in Patients With Schizophrenia: A Meta-analysis of Existing Findings and New Data in a First-Episode Sample Patients with established schizophrenia (meta-analysis: 572) and patients with... | 2010 | Meta-analysis and cross-sectional observational study | n = 700 |
| Medicinal cannabis for psychiatric disorders: a clinically-focused systematic review | 2020 | Systematic review | |
| Neuroimaging in cannabis use: a systematic review of the literature Cannabis users and controls in neuroimaging studies | 2009 | Systematic review | |
| Human Laboratory Studies on Cannabinoids and Psychosis. Healthy human subjects and individuals with schizophrenia | 2016 | Systematic review |
Citations in the library
Cites 13
- Acute memory and psychotomimetic effects of cannabis and tobacco both ‘joint’ and individually: a placebo-controlled trial Psychological Medicine May 30, 2017
- Anatomy of a Joint: Comparing Self-Reported and Actual Dose of Cannabis and Tobacco in a Joint, and How These Are Influenced by Controlled Acute Administration Cannabis and Cannabinoid Research 2017
- Effects of different methods of cannabis use on cognition and blood THC: A systematic review. Progress in Neuro-Psychopharmacology and Biological Psychiatry May 1, 2025
- Evidence on the acute and residual neurocognitive effects of cannabis use in adolescents and adults: a systematic meta-review of meta-analyses. Addiction January 19, 2022
- Acute effects of partial CB1 receptor agonists on cognition - A meta-analysis of human studies. Progress in Neuro-Psychopharmacology and Biological Psychiatry August 10, 2020
and 8 more in the library