Large study found slower startle responses predicted psychosis conversion, with cannabis altering sensory gating differently in at-risk individuals
Among 543 individuals at clinical high risk for psychosis, those who later converted had significantly slower startle response latency, and cannabis use was associated with increased sensory gating (PPI) in at-risk individuals but not in healthy controls.
Quick Facts
What This Study Found
CHR participants who converted to psychosis had significantly slower startle latency than non-converters, driven by female participants. PPI showed a significant group-by-cannabis interaction: cannabis users in the CHR group had greater PPI than non-users, opposite to the pattern in healthy controls. PPI correlated significantly with age in CHR but not healthy participants.
Key Numbers
543 CHR participants, 218 healthy controls, ages 12-35. 58 CHR participants converted to psychosis at 1-year follow-up. Significant group-by-cannabis interaction on PPI. Slower startle latency predicted conversion, driven by females.
How They Did This
Prospective study of 543 CHR and 218 normal comparison participants aged 12-35 from the NAPLS consortium. Startle reactivity, latency, and prepulse inhibition were measured at baseline, with psychotic conversion assessed at 1-year follow-up.
Why This Research Matters
Identifying biomarkers that predict who among at-risk individuals will develop psychosis could enable earlier intervention. The finding that cannabis alters sensory gating differently in this population suggests distinct neurobiological effects.
The Bigger Picture
The opposite pattern of cannabis effects on sensory gating in at-risk vs. healthy individuals suggests that cannabis interacts with already-altered brain circuits in people vulnerable to psychosis, rather than simply impairing everyone equally.
What This Study Doesn't Tell Us
Observational design; cannabis use was self-reported and not experimentally controlled; 1-year follow-up may miss later conversions; the sex-specific latency finding needs replication.
Questions This Raises
- ?Why do at-risk cannabis users show enhanced rather than reduced sensory gating?
- ?Could startle latency be used clinically to identify females at highest conversion risk?
Trust & Context
- Key Stat:
- 58 of 543 clinical high-risk participants converted to psychosis within one year
- Evidence Grade:
- Large prospective cohort from a well-established consortium (NAPLS), with replication of age-PPI findings from a prior sample.
- Study Age:
- Published in 2020.
- Original Title:
- Evidence of Slow Neural Processing, Developmental Differences and Sensitivity to Cannabis Effects in a Sample at Clinical High Risk for Psychosis From the NAPLS Consortium Assessed With the Human Startle Paradigm.
- Published In:
- Frontiers in psychiatry, 11, 833 (2020)
- Authors:
- Cadenhead, Kristin S(2), Duncan, Erica, Addington, Jean(4), Bearden, Carrie, Cannon, Tyrone D, Cornblatt, Barbara A, Mathalon, Dan, McGlashan, Thomas H, Perkins, Diana O, Seidman, Larry J, Tsuang, Ming, Walker, Elaine F, Woods, Scott W, Bauchman, Peter, Belger, Ayse, Carrión, Ricardo E, Donkers, Franc, Johannesen, Jason, Light, Gregory, Niznikiewicz, Margaret, Nunag, Jason, Roach, Brian
- Database ID:
- RTHC-02445
Evidence Hierarchy
Enrolls participants and follows them forward in time.
What do these levels mean? →Frequently Asked Questions
Did cannabis use predict psychosis in this study?
The study did not find a direct cannabis-to-psychosis link. Instead, it found that cannabis affected a brain biomarker (prepulse inhibition) differently in at-risk individuals compared to healthy controls, suggesting cannabis interacts with already-altered neural circuits in vulnerable people.
What is prepulse inhibition and why does it matter?
PPI is a measure of sensory gating, the brain's ability to filter out irrelevant stimuli. Deficits in PPI are commonly seen in psychotic disorders. The finding that cannabis increased PPI in at-risk individuals (opposite to healthy controls) suggests complex interactions between cannabis and psychosis-related brain changes.
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Cite This Study
https://rethinkthc.com/research/RTHC-02445APA
Cadenhead, Kristin S; Duncan, Erica; Addington, Jean; Bearden, Carrie; Cannon, Tyrone D; Cornblatt, Barbara A; Mathalon, Dan; McGlashan, Thomas H; Perkins, Diana O; Seidman, Larry J; Tsuang, Ming; Walker, Elaine F; Woods, Scott W; Bauchman, Peter; Belger, Ayse; Carrión, Ricardo E; Donkers, Franc; Johannesen, Jason; Light, Gregory; Niznikiewicz, Margaret; Nunag, Jason; Roach, Brian. (2020). Evidence of Slow Neural Processing, Developmental Differences and Sensitivity to Cannabis Effects in a Sample at Clinical High Risk for Psychosis From the NAPLS Consortium Assessed With the Human Startle Paradigm.. Frontiers in psychiatry, 11, 833. https://doi.org/10.3389/fpsyt.2020.00833
MLA
Cadenhead, Kristin S, et al. "Evidence of Slow Neural Processing, Developmental Differences and Sensitivity to Cannabis Effects in a Sample at Clinical High Risk for Psychosis From the NAPLS Consortium Assessed With the Human Startle Paradigm.." Frontiers in psychiatry, 2020. https://doi.org/10.3389/fpsyt.2020.00833
RethinkTHC
RethinkTHC Research Database. "Evidence of Slow Neural Processing, Developmental Difference..." RTHC-02445. Retrieved from https://rethinkthc.com/research/cadenhead-2020-evidence-of-slow-neural
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.