Gender, MAOA Genotype, and History of Child Abuse Predict Tobacco and Cannabis Use

Sex-dimorphic interactions between the monoamine oxidase A (MAOA) gene and a history of child abuse increases vulnerability to the use of tobacco and cannabis, according to the results of a study published in CNS Neuroscience and Therapeutics.

Epidemiologic surveys have indicated that college students in the United States and other Western countries have a high rate of alcohol, tobacco, and cannabis abuse. Such abuse can have serious consequences, including neurocognitive problems, health concerns, poor academic performance, financial and legal repercussions, and even increased injury and death. Evidence has suggested that the risk for substance use, and particularly early use, is affected by the MAOA gene, which encodes the enzyme that catalyzes the oxidative deamination of brain monoamine transmitters such as serotonin, norepinephrine, and dopamine. These in turn play major roles in the stress response and the pathophysiology of substance abuse.

Paula J. Fite, PhD, of the Consortium for Translational Research on Aggression and Drug Abuse and the Clinical Child Psychology Program at the University of Kansas in Lawrence, and colleagues, surveyed 500 college students from a large Midwestern University for child maltreatment history, including physical, emotional, or sexual abuse, and for the consumption of tobacco and cannabis. They determined the MAOA uVNTR genotype of each participant using saliva samples.

In female students, the interaction of childhood physical and emotional abuse with high-activity MAOA allelic variants was associated with increased tobacco and cannabis use. In contrast, in male students, low-activity MAOA allelic variants in combination with childhood physical abuse correlated with increased tobacco use, but not cannabis use.

The investigators noted that the study was limited by the homogeneous nature of the college student population, which was primarily white. Another limitation was the use of only 3 variables: gender, the MAOA gene, and a history of child abuse. Other environmental and genetic factors may be involved. The study also surveyed the use, but not the frequency, of the substances, and the information on childhood maltreatment was based on retrospective self-reports.

The investigators noted that these findings underscore the importance of gender as a factor in these analyses. They suggest that it is possible that sex factors may be critical in differentiating the response to stress with respect to specific gene pathways. They also argue that their results may have implications for the prevention of substance use.

Reference

Fite PJ, Brown S, Hossain W, Manzardo A, Butler MG, Bortolato M. Tobacco and cannabis use in college students are predicted by sex-dimorphic interactions between MAOA genotype and child abuse [published online June 27, 2018]. CNS Neurosci Ther. doi:10.1111/cns.13002