Cannabis use worsened attention in adolescents with schizophrenia but not in healthy teens
Cannabis use disorder impaired executive attention in adolescents with schizophrenia but not in healthy adolescents, suggesting cannabis has a selectively harmful effect on attention in the context of psychotic illness.
Quick Facts
What This Study Found
Researchers compared attention performance across four groups of adolescents: early-onset schizophrenia with cannabis use disorder (EOS+CUD, n=18), schizophrenia only (EOS, n=34), cannabis use disorder only (CUD, n=29), and healthy controls (n=53). A significant interaction emerged: in the executive attention network, adolescents with both schizophrenia and cannabis use disorder performed worse than those with schizophrenia alone.
However, adolescents with cannabis use disorder alone showed no difference from healthy controls. This selective effect suggests that cannabis has a moderating impact on attention specifically in the context of schizophrenia.
The attention deficit was associated with smaller surface area in the right caudal anterior cingulate cortex, suggesting an anatomical substrate for the cognitive impairment.
Key Numbers
134 adolescents across four groups. Significant EOS x CUD interaction in executive attention. Attention deficit correlated with smaller right caudal anterior cingulate cortex surface area in the EOS+CUD group.
How They Did This
Four-group comparison using the Attention Network Test during fMRI in 134 adolescents. 2x2 design crossing EOS status with CUD status. Brain surface area in the anterior cingulate cortex was measured and correlated with attention performance.
Why This Research Matters
Cannabis use is common among people with schizophrenia, and understanding whether it worsens the cognitive deficits of the illness has direct clinical implications. The selective interaction found here suggests cannabis may specifically compound schizophrenia-related cognitive problems.
The Bigger Picture
This study adds nuance to the cannabis-psychosis literature by showing that the cognitive effects of cannabis may depend on underlying brain state. Rather than a universal effect, cannabis may be particularly harmful to brain functions already compromised by psychotic illness.
What This Study Doesn't Tell Us
Cross-sectional design. Relatively small group sizes, especially the EOS+CUD group (n=18). Cannot determine whether cannabis caused the attention deficit or whether more severely affected patients were more likely to use cannabis. The results are described as preliminary.
Questions This Raises
- ?Does cannabis cessation improve attention in adolescents with schizophrenia?
- ?Is the anterior cingulate cortex difference a consequence of cannabis use, schizophrenia, or both?
- ?Would these findings replicate in adult schizophrenia populations?
Trust & Context
- Key Stat:
- Cannabis impaired attention in schizophrenia but not in healthy adolescents
- Evidence Grade:
- Well-designed four-group comparison with brain imaging correlation, though limited by small subgroup sizes and cross-sectional design.
- Study Age:
- Published in 2014.
- Original Title:
- Executive attention impairment in adolescents with schizophrenia who have used cannabis.
- Published In:
- Schizophrenia research, 157(1-3), 48-54 (2014)
- Authors:
- Epstein, Katherine A, Kumra, Sanjiv(2)
- Database ID:
- RTHC-00792
Evidence Hierarchy
A snapshot of a population at one point in time.
What do these levels mean? →Frequently Asked Questions
Does cannabis make schizophrenia worse?
This study found that cannabis use disorder impaired executive attention specifically in adolescents who already had schizophrenia, but not in healthy adolescents. This suggests cannabis may selectively worsen cognitive functions already compromised by psychotic illness.
Did cannabis affect attention in healthy teenagers?
No. Adolescents with cannabis use disorder alone performed no differently from healthy controls on the Attention Network Test. The harmful effect of cannabis on attention appeared only in those who also had schizophrenia.
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Cite This Study
https://rethinkthc.com/research/RTHC-00792APA
Epstein, Katherine A; Kumra, Sanjiv. (2014). Executive attention impairment in adolescents with schizophrenia who have used cannabis.. Schizophrenia research, 157(1-3), 48-54. https://doi.org/10.1016/j.schres.2014.04.035
MLA
Epstein, Katherine A, et al. "Executive attention impairment in adolescents with schizophrenia who have used cannabis.." Schizophrenia research, 2014. https://doi.org/10.1016/j.schres.2014.04.035
RethinkTHC
RethinkTHC Research Database. "Executive attention impairment in adolescents with schizophr..." RTHC-00792. Retrieved from https://rethinkthc.com/research/epstein-2014-executive-attention-impairment-in
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.