Influence of recent cannabis use on altered spectral entropy modulation and connectivity strength in patients with psychosis
Vicente Molina, Alvaro Diez, Inés Fernández-Linsenbarth, Emma Osorio-Iriarte, Rosa Beño-ruiz de la Sierra, Óscar Martín-Santiago, Claudia Rodríguez-valbuena, J. C. Fiorini-Talavera, Antonio Arjona
European Archives of Psychiatry and Clinical Neuroscience June 23, 2025 DOI: 10.1007/s00406-025-02004-0 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cross-sectional study Peer reviewed |
|---|---|
| Sample size | 179 |
| Population | 93 patients with psychosis (schizophrenia or bipolar disorder; 32 recent cannabis users, 61 non-users) and 86 age- and sex-matched healthy controls (all non-users) |
| Topics | Cannabis |
| Key findings | Both patient groups showed significantly impaired spectral entropy modulation and elevated gamma and broadband connectivity strength compared with healthy controls, but no significant differences were found between cannabis-using and non-using patients on any EEG measure. The authors conclude that recent cannabis use does not appear to be the primary driver of these electrophysiological alterations, suggesting they may be core features of psychosis and possible vulnerability markers. |
Abstract
Cannabis use is highly prevalent in individuals with psychosis, raising concerns about its influence on brain function. Electroencephalography (EEG) studies have identified alterations in brain activity in psychosis, including changes in spectral entropy (SE) modulation and connectivity strength (CS). However, the degree to which cannabis use contributes to these alterations remains unclear. This study investigated the effects of recent cannabis use on specific EEG measures previously found to be altered in psychosis: (i) SE modulation, (ii) pre-stimulus theta and broadband CS, and (iii) baseline CS in the gamma band. We focused specifically on the immediate effects of recent cannabis use, without considering factors like tetrahydrocannabinol content, frequency of use, or age of onset. We included 93 patients with psychosis (32 recent cannabis users, 61 non-users) and 86 age- and sex-matched healthy controls (HC; all non-users). Recent cannabis use was defined as any consumption within the past week, assessed through a clinical interview and confirmed by urinalysis. Patients had diagnosis of schizophrenia or bipolar disorder. EEG data were recorded during a P300 task, and SE modulation and baseline CS were calculated. Both patient groups (cannabis users and non-users) exhibited significantly impaired SE modulation and elevated gamma and broadband CS, compared to HC. Crucially, no significant differences were found between the two patient groups in any of the EEG measures. Recent cannabis use does not appear to be the primary driver of the observed electrophysiological alterations in psychosis. Impaired SE modulation and increased CS are likely core features of psychosis itself, independent of recent cannabis exposure. This suggests that these EEG abnormalities may represent underlying vulnerability markers for psychosis. However, further research is needed to explore the potential long-term and early-onset effects of cannabis use on brain function in individuals with psychosis.
Comparable studies
Other cross-sectional and survey studies on cannabis, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Cannabis use before age 15 and subsequent executive functioning 104 chronic cannabis users (49 early-onset before age 15, 55 late-onset after age 15)... | 2011 | Observational cross-sectional study | n = 148 |
| Patterns of simultaneous polysubstance use in drug using university students Drug-using university students | 2006 | Cross-sectional survey | n = 149 |
| Persisting Reductions in Cannabis, Opioid, and Stimulant Misuse After Naturalistic Psychedelic Use: An Online Survey Online survey respondents | 2020 | Cross-sectional survey | |
| User perceptions of the benefits and harms of hallucinogenic drug use: A web-based questionnaire study Users of hallucinogenic drugs who completed a web-based questionnaire | 2010 | Cross-sectional survey | n = 600 |
| Illicit Use of LSD or Psilocybin, but not MDMA or Nonpsychedelic Drugs, is Associated with Mystical Experiences in a Dose-Dependent Manner Adults recruited from the MAPS website and newsletter, most reporting use of various... | 2012 | Cross-sectional survey | n = 337 |
Citations in the library
Cites 4
- Human Laboratory Studies on Cannabinoids and Psychosis. Biological Psychiatry April 1, 2016
- The contribution of cannabis use to variation in the incidence of psychotic disorder across Europe (EU-GEI): a multicentre case-control study The Lancet Psychiatry May 1, 2019
- Cannabis and schizophrenia. Cochrane Database of Systematic Reviews October 14, 2014
- The effect of chronic cannabinoids on broadband EEG neural oscillations in humans. Neuropsychopharmacology September 2012