Genetic Links to Drug and Alcohol Use Among Young People With Mental Health Risks

Young people who are genetically predisposed to risk-taking, low extraversion and schizophrenia are more likely to use alcohol, cigarettes, cannabis or other illicit drugs, according to a new University College London-led study.

The researchers say that the findings, published in Addiction Biology, are in line with the notion that people who are more vulnerable to psychopathology or certain personality traits are more inclined to try several types of drugs or use them to 'self-medicate'.

The study used data from the Avon Longitudinal Study of Parents and Children (n=4218) and applied trait‐state‐occasion models to delineate the common and substance‐specific factors based on four classes of substances (alcohol, cigarettes, cannabis and other illicit substances) assessed over time (ages 17, 20 and 22 years). The researchers generated 18 polygenic scores indexing genetically influenced mental health vulnerabilities and individual traits.

The results implicated several genetically influenced traits and vulnerabilities in the common liability to substance use, most notably risk taking (b_standardised, 0.14; 95% CI, 0.10-0.17), followed by extraversion (b_standardised, −0.10; 95% CI, −0.13 to −0.06) and schizophrenia risk (b_standardised, 0.06; 95% CI, 0.02-0.09).

Educational attainment (EA) and body mass index (BMI) had opposite effects on substance‐specific liabilities such as cigarette use (b_{standardised‐EA}, −0.15; 95% CI, −0.19 to −0.12 and b_{standardised‐BMI}, 0.05; 95% CI, 0.02-0.09) and alcohol use (b_{standardised‐EA}, 0.07; 95% CI, 0.03-0.11 and b_{standardised‐BMI}, −0.06; 95% CI, −0.10 to −0.02).

These findings point towards largely distinct sets of genetic influences on the common versus specific liabilities.

Co-lead author Dr Tabea Schoeler (UCL Psychology and Language Sciences) said: “Treatment and prevention programmes that target risk-taking behaviours among young people, while also focusing on adolescents with early signs of schizophrenia, could be beneficial in reducing the risk of developing substance use problems.”