Genetic and Environmental Influences on Gambling: A Meta-Analysis of Twin Studies.
Level 3 - non-randomized controlled study
Meta-analysis of observational twin studies (level 3 by design analogy).
PubMed 29259572 · doi:10.3389/fpsyg.2017.02121
What was done
The authors conducted a systematic review and meta-analysis of 18 twin studies to estimate the proportions of total variance in gambling behavior explained by additive genes (A), dominant genes (D), shared environment (C), and non-shared environment plus measurement error (E). Moderation analyses examined gambling assessment type (symptom-oriented vs. behavior-oriented), age (adults vs. adolescents), and sex.
What was found
Across the whole sample, additive genetic factors (a² = 0.50) and non-shared environment (e² = 0.50) each accounted for 50% of the variance in gambling behavior. Genetic influence was higher for symptom-oriented disordered gambling (53%) than behavior-oriented gambling (41%), and higher in adults (53%) than adolescents (42%). Genetic influence was greater for males (47%) than females (28%), whereas shared environment accounted for 14% of the variance in females (c² = 0.14) and 0% in males.
Why it matters
This meta-analysis quantifies the relative contributions of heritability and environment to gambling behavior, demonstrating equal overall contributions of genes and non-shared environment while highlighting significant moderation by sex, age, and clinical severity.
Limits
The meta-analysis included a relatively small total number of studies (18 twin studies), and the abstract does not report the total participant count. Twin modeling cannot pinpoint specific biological pathways or specific environmental factors, and non-shared environment estimates (E) inherently include measurement error.
Cited by
- contradicts Asians, and particularly Asian women, carry a genetic predisposition to gambling at higher rates than other racial groups.