Psychosis Without Cannabis History Shows Worse Eye Movement Control
Patients with early psychosis who had never used cannabis showed worse smooth pursuit eye movement performance than patients whose psychosis developed in the context of cannabis use.
Quick Facts
What This Study Found
Among 91 participants across four groups, early psychosis patients without cannabis history had significantly worse smooth pursuit velocity gain compared to those with cannabis history (effect size g=0.76-0.86), suggesting less severe neurobiological alterations in cannabis-associated psychosis.
Key Numbers
91 participants (28 psychosis+cannabis, 25 psychosis no cannabis, 16 controls+cannabis, 22 controls no cannabis); smooth pursuit impairment effect size g=0.76-0.86 between psychosis groups; significant patient x cannabis interaction (p=0.04).
How They Did This
Case-control study comparing four groups (psychosis with/without cannabis history, controls with/without cannabis) on smooth pursuit eye movements at three frequencies and antisaccade performance.
Why This Research Matters
If psychosis that develops with cannabis use involves less severe underlying brain abnormalities than psychosis without cannabis, it could have implications for prognosis and treatment approaches.
The Bigger Picture
These findings align with the theory that cannabis-associated psychosis may represent a less neurobiologically impaired subtype, where the substance itself contributes substantially to pushing someone over the psychosis threshold.
What This Study Doesn't Tell Us
Small sample sizes in each group; cross-sectional design; cannabis use history was self-reported; medication effects could influence eye movements.
Questions This Raises
- ?Do patients with cannabis-associated psychosis have better long-term outcomes if they stop using?
- ?Could eye movement testing help distinguish psychosis subtypes?
Trust & Context
- Key Stat:
- Large effect size (g=0.76-0.86) showing worse eye movement control in psychosis patients without cannabis history
- Evidence Grade:
- Small case-control study with novel neurobiological measures, limited by sample size and cross-sectional design.
- Study Age:
- Published in 2021.
- Original Title:
- Eye movements in patients in early psychosis with and without a history of cannabis use.
- Published In:
- NPJ schizophrenia, 7(1), 24 (2021)
- Authors:
- Sami, Musa Basseer(2), Annibale, Luciano(3), O'Neill, Aisling(5), Collier, Tracy, Onyejiaka, Chidimma, Eranti, Savitha, Das, Debasis, Kelbrick, Marlene, McGuire, Philip, Williams, Steve C R, Rana, Anas, Ettinger, Ulrich, Bhattacharyya, Sagnik
- Database ID:
- RTHC-03491
Evidence Hierarchy
Compares people with a condition to similar people without it.
What do these levels mean? →Frequently Asked Questions
What do eye movements reveal about psychosis?
Smooth pursuit eye movement impairment is a well-established marker of neurobiological dysfunction in psychosis. This study found worse impairment in patients whose psychosis developed without cannabis use.
Does this mean cannabis-caused psychosis is less severe?
The findings suggest that when psychosis develops in the context of cannabis use, the underlying brain abnormalities may be less severe than in psychosis that develops without cannabis. However, more research is needed.
Read More on RethinkTHC
- THC-amygdala-anxiety-brain
- anandamide-weed-withdrawal
- cannabinoid-receptors-recovery-time
- cannabis-developing-brain-teenagers
- cant-enjoy-anything-without-weed
- dopamine-recovery-after-quitting-weed
- endocannabinoid-system-explained-simply
- endocannabinoid-system-withdrawal
- nervous-system-weed-withdrawal-fight-flight
- teen-weed-use-under-18-effects-brain
- thc-brain-withdrawal
- thc-prefrontal-cortex-brain-effects
- weed-cortisol-stress-hormones
- weed-memory-loss-recovery
- weed-motivation-amotivational-syndrome
- weed-nervous-system-effects
- weed-reward-system-brain
Cite This Study
https://rethinkthc.com/research/RTHC-03491APA
Sami, Musa Basseer; Annibale, Luciano; O'Neill, Aisling; Collier, Tracy; Onyejiaka, Chidimma; Eranti, Savitha; Das, Debasis; Kelbrick, Marlene; McGuire, Philip; Williams, Steve C R; Rana, Anas; Ettinger, Ulrich; Bhattacharyya, Sagnik. (2021). Eye movements in patients in early psychosis with and without a history of cannabis use.. NPJ schizophrenia, 7(1), 24. https://doi.org/10.1038/s41537-021-00155-2
MLA
Sami, Musa Basseer, et al. "Eye movements in patients in early psychosis with and without a history of cannabis use.." NPJ schizophrenia, 2021. https://doi.org/10.1038/s41537-021-00155-2
RethinkTHC
RethinkTHC Research Database. "Eye movements in patients in early psychosis with and withou..." RTHC-03491. Retrieved from https://rethinkthc.com/research/sami-2021-eye-movements-in-patients
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.