Related Experiment Video
Updated: Mar 10, 2026
07:30
Brain Morphology of Cannabis Users With or Without Psychosis: A Pilot MRI Study
Published on: August 18, 2020
8.0K
Assessing causality in associations between cannabis use and schizophrenia risk: a two-sample Mendelian randomization
S H Gage1, H J Jones1, S Burgess2
1MRC Integrative Epidemiology Unit (IEU), University of Bristol,Bristol,UK.
Psychological Medicine
|December 9, 2016
Summary
This study suggests cannabis initiation may slightly increase schizophrenia risk. However, schizophrenia risk appears to more strongly predict cannabis initiation, possibly due to genetic factors.
Area of Science:
- Psychiatry
- Genetics
- Epidemiology
Background:
- Observational studies link cannabis use to schizophrenia, but causation remains unclear.
- Mendelian randomization (MR) is a method to infer causation from observational data.
- This study utilizes publicly available genome-wide association data.
Purpose of the Study:
- To investigate the causal relationship between cannabis initiation and schizophrenia risk.
- To explore the potential causal effect of schizophrenia risk on cannabis initiation.
- To apply bi-directional two-sample MR for robust causal inference.
Main Methods:
- Bi-directional two-sample MR was performed using summary-level data.
- Genome-wide association study data from the International Cannabis Consortium and Psychiatric Genomics Consortium were utilized.
- Single nucleotide polymorphisms (SNPs) for cannabis initiation and schizophrenia were identified and analyzed.
Main Results:
- Some evidence suggests cannabis initiation causally increases schizophrenia risk (OR 1.04).
- Stronger evidence indicates schizophrenia risk causally influences cannabis initiation (OR 1.10).
- Control analyses for height and education supported the methodology.
Conclusions:
- Cannabis initiation may have a small causal effect on increasing schizophrenia risk.
- Schizophrenia risk appears to be a stronger predictor of cannabis initiation.
- Genetic instrument strength may explain the asymmetry in causal findings.
Related Concept Videos
01:29Biological Causes of Schizophrenia
887
Schizophrenia, a severe psychiatric disorder, arises from a complex interplay of biological factors, including genetic predisposition, structural brain abnormalities, neurotransmitter dysregulation, and developmental irregularities. These factors collectively contribute to the onset and progression of the disorder, which typically manifests in late adolescence or early adulthood.
Genetic Factors in Schizophrenia
The genetic basis of schizophrenia is strongly supported by family and twin...
Genetic Factors in Schizophrenia
The genetic basis of schizophrenia is strongly supported by family and twin...
887
01:29Psychological and Sociocultural Causes of Schizophrenia
742
Schizophrenia, a complex psychiatric disorder, has been historically misunderstood. Early psychological theories attributed its origins to childhood trauma and unresponsive parenting. However, contemporary research largely rejects these notions, favoring the vulnerability-stress hypothesis. This model proposes that individuals with a genetic predisposition to schizophrenia may develop the disorder following exposure to significant environmental stressors. Notably, studies on high-risk...
742
01:11Genome-wide Association Studies-GWAS
16.4K
Genome-wide association studies or GWAS are used to identify whether common SNPs are associated with certain diseases. Suppose specific SNPs are more frequently observed in individuals with a particular disease than those without the disease. In that case, those SNPs are said to be associated with the disease. Chi-square analysis is performed to check the probability of the allele likely to be associated with the disease.
GWAS does not require the identification of the target gene involved in...
GWAS does not require the identification of the target gene involved in...
16.4K
01:21Causality in Epidemiology
1.8K
Causality or causation is a fundamental concept in epidemiology, vital for understanding the relationships between various factors and health outcomes. Despite its importance, there's no single, universally accepted definition of causality within the discipline. Drawing from a systematic review, causality in epidemiology encompasses several definitions, including production, necessary and sufficient, sufficient-component, counterfactual, and probabilistic models. Each has its strengths and...
1.8K
01:27Psychosis: Pathophysiology of Schizophrenia and Other Psychotic Disorders
2.3K
Schizophrenia is a neurodevelopmental disorder whose origins are rooted in complex genetic components. Despite our burgeoning understanding, the pathophysiology of this disorder remains incompletely deciphered.
Researchers have identified genetic factors that increase susceptibility to schizophrenia, underscoring the intricate interplay between genetics and environment in disease development. At the core of schizophrenia's pathophysiology is excessive dopaminergic neurotransmission within...
Researchers have identified genetic factors that increase susceptibility to schizophrenia, underscoring the intricate interplay between genetics and environment in disease development. At the core of schizophrenia's pathophysiology is excessive dopaminergic neurotransmission within...
2.3K
01:28Criteria for Causality: Bradford Hill Criteria - II
1.4K
The Bradford Hill criteria serve as guidelines for establishing causative links in epidemiological research. Beyond Strength, Consistency, Specificity, and Temporality, key criteria also include Biological Gradient, Plausibility, Coherence, Experiment, and Analogy. These principles assist scientists in assessing the likelihood of causation in complex biological contexts. Below is a summary of these concepts:
1.4K