May 2026
Cannabis
What May 2026's 9 new studies found, synthesized from the papers below. All Cannabis research →
The synthesis
Synthesized from 5 studies in the library · AI-generated, grounded in the abstracts below
Found by searching the library for Cannabis, marijuana, THC, cannabidiol, CBD, then ranked by relevance.
Research on cannabis published in May 2026 found that THC impairs memory, alters brain connectivity, and worsens driving performance, especially when combined with alcohol. Effects on executive function were mixed and varied by age and region. A key caveat is that many studies used small samples or animal models, limiting generalizability.
Evidence by study
Direction is which way each study's own result points, not our rating of the study.
What the directions mean
- Supports:
- the study found the intervention worked, or its hypothesis held.
- Opposes:
- it found the opposite, no benefit or a harm.
- No effect:
- no significant difference either way.
- Mixed:
- effects in both directions within the same study.
- Unclear:
- the abstract does not report a direction.
| Study | Design | Sample size | Direction | Finding |
|---|---|---|---|---|
| Neuropsychological effects of cannabis use by continent and age: a systematic review 2026 | systematic review | 22 | Opposes | Memory impairments were the most consistent finding across studies, while executive function results were heterogeneous. |
| Effects of THC, CBD, and Their Combination on EEG Dynamics in Rats. 2026 | animal study | Supports | THC and THC+CBD increased low-frequency EEG power and altered functional connectivity in brain regions rich in CB1 receptors. | |
| Δ9-Tetrahydrocannabinol Alters Limbic and Frontal Functional Brain Connectomes Among Young Adult Cannabis Users. 2026 | RCT | 33 | Opposes | Acute THC reduced within-network connectivity in corticostriatal and sensory networks, and reduced between-network connectivity in limbic and frontal regions. |
| Effects of acute THC challenge on behavior and neuroinflammation in HIV-1 Tg26 mice vary based on HIV status, chronic THC history, and sex. 2026 | animal study | 63 | Mixed | Chronic THC history led to minor behavioral changes and overall decreases in cytokines/chemokines, with effects varying by HIV status and sex. |
| Impact of Cannabis Edibles Combined With Alcohol on Driving, Field Sobriety Performance, and Subjective Effects: A Within-Participant Crossover Trial. 2026 | RCT | 25 | Opposes | Cannabis edibles alone and with alcohol impaired driving performance and field sobriety tests, with additive effects when combined. |
Memory impairments were the most consistent finding across studies, while executive function results were heterogeneous.
systematic review Sample size: 22
THC and THC+CBD increased low-frequency EEG power and altered functional connectivity in brain regions rich in CB1 receptors.
animal study
Acute THC reduced within-network connectivity in corticostriatal and sensory networks, and reduced between-network connectivity in limbic and frontal regions.
RCT Sample size: 33
Chronic THC history led to minor behavioral changes and overall decreases in cytokines/chemokines, with effects varying by HIV status and sex.
animal study Sample size: 63
Cannabis edibles alone and with alcohol impaired driving performance and field sobriety tests, with additive effects when combined.
RCT Sample size: 25
Points of agreement
- THC consistently impairs memory and alters brain connectivity.
- Cannabis impairs driving performance, especially when combined with alcohol.
- Animal models show THC alters EEG dynamics and neuroinflammatory markers.
Conflicts
- Executive function findings were heterogeneous across studies in the systematic review.
- Chronic THC history produced only minor behavioral changes in mice, contrasting with acute effects in humans.
Gaps
- Long-term durability of cognitive impairments is not addressed.
- Effects in older adults or clinical populations are not studied.
- Dose-response relationships and sex differences are underexplored in human studies.
- Real-world driving performance after cannabis use is not assessed.