Schizophrenia with heavy cannabis use showed different brain structure than cannabis-induced psychosis | Research

The takeaway

Brain imaging revealed that schizophrenia patients with heavy cannabis use had thinner cortex than both cannabis-induced psychosis patients and healthy controls, suggesting these are structurally distinct conditions.

Psychiatrists, neuroimaging researchers, and clinicians distinguishing cannabis-induced psychosis from schizophrenia.

SZC had significantly thinner cortex than both CIP and healthy controls

What the researchers found

Schizophrenia with heavy cannabis use (SZC) showed the lowest cortical thickness, depth, and gyrification, followed by cannabis-induced psychosis (CIP), then healthy controls. SZC had significantly thinner cortex than controls in frontal regions and thinner than CIP in postcentral and frontal regions. Duration of cannabis use negatively correlated with cortical thickness in parietal and occipital areas.

Why it matters

Distinguishing cannabis-induced psychosis from schizophrenia has important treatment implications. Different brain structural profiles support different underlying pathophysiology.

The numbers in context

31 SZC, 28 CIP, 30 controls. SZC had reduced cortical thickness vs controls in middle/inferior frontal and other regions. SZC was also thinner than CIP in bilateral postcentral and right middle frontal regions.

How the study worked

Cross-sectional brain MRI study comparing 31 men with schizophrenia and heavy cannabis use, 28 with cannabis-induced psychosis, and 30 healthy controls. Surface-based brain morphometry using the CAT-12 toolbox with cortical parcellation.

What this study cannot tell us

Small sample size. All male participants. Cross-sectional design cannot determine whether brain differences preceded or resulted from cannabis use or illness. Only one imaging modality.

How to read the evidence

Rigorous neuroimaging methodology with appropriate controls, but small sample size and cross-sectional design limit conclusions.

When this study was published

Published in 2022.

The bigger picture

The cortical thickness gradient (SZC < CIP < controls) suggests schizophrenia involves more severe structural brain changes than cannabis-induced psychosis, supporting the clinical distinction between these diagnoses.

Questions still open

Do CIP patients who later develop schizophrenia show intermediate cortical thickness? Could brain imaging help predict which CIP patients will progress to schizophrenia?

Common questions

Are cannabis-induced psychosis and schizophrenia the same condition?

This study suggests they are structurally different. Schizophrenia patients with cannabis use had significantly thinner cortex than cannabis-induced psychosis patients, indicating different levels of brain structural changes.

Did cannabis use duration affect brain structure?

Yes. Longer duration of cannabis use was correlated with thinner cortex in parietal and occipital regions, suggesting cumulative effects on brain structure.

Read the original research

Surface-based brain morphometry in schizophrenia vs. cannabis-induced psychosis: A controlled comparison.

Journal of psychiatric research, 155, 286-294

View on PubMed ↗Publisher’s paper ↗

Citation

Ghosh, Abhishek; Kaur, Simranjit; Shah, Raghav; Oomer, Fareed; Avasthi, Ajit; Ahuja, Chirag K; Basu, Debasish; Nehra, Ritu; Khandelwal, Niranjan. (2022). Surface-based brain morphometry in schizophrenia vs. cannabis-induced psychosis: A controlled comparison.. Journal of psychiatric research, 155, 286-294. https://doi.org/10.1016/j.jpsychires.2022.09.034