What makes some of us more likely to drive over the speed limit, participate in extreme sports or make decisions that can impact health over time? Risk-taking behavior has distinct subtypes (for example disinhibition, sensation seeking, calculated risks, impulsivity) that develop due to the complex interplay of different factors: our lifestyle and environment, our personal susceptibility (genetic and biological variants) and a wide range of psychological effects.

In the study of Strawbridge and colleagues (2018) the goal was to identify genetic determinants of this trait. This approach has the potential to improve our understanding of impulsive behavior across different psychiatric disorders. It can also help later on to explore the possible overlap between mental illnesses and physical health.

„Would you consider yourself a risk taker?” This was the question posed to 116,255 participants, aged 40 to 69, from the UK Biobank project, a large population cohort containing a wide range of sociodemographic and medical information. Roughly one-quarter answered yes, they were the ’risk takers’ group.

A subset of participants took part in a prolonged follow-up occasion as well, where the same question was asked enabling an assessment of response consistency. Reproducibility was quite good, 81% of all participants responded consistently, 13% inconsistently, while in 6% the data was missing.

Genetic loci associated with risk-taking behavior were explored using the genome-wide association study approach. The authors identified one potential locus on chromosome 3 (CADM2) consistently, which was previously implicated in cognitive and executive functions.

Considering the entire genome using the polygenic risk score approach, the authors found, that the genetic variants that make us risk-prone also make us more likely to develop mental illnesses, such as bipolar disorder, schizophrenia, attention-deficit hyperactivity disorder, and post-traumatic stress disorder.

This trait has not only significant positive genetic correlations with a range of mental health disorders, but also with smoking, lifetime cannabis use and body mass index (BMI). The latter implies the possibility that this finding could be followed up in a study exploring the nutritional aspects of impulsivity as well.

Overall, using dimensional approach for traits (from “normal” to pathological) rather than discrete diagnostic categories could be helpful for finding the common ground in the neurobiological underpinnings across psychiatric disorders. From this point of view, risk-taking behavior is also a complex and important phenotype for investigations.

You can find the full research article here.

Strawbridge, R. J., Ward, J., Cullen, B., Tunbridge, E. M., Hartz, S., Bierut, L., Horton, A., Bailey, M. E. S., Graham, N., Ferguson, A., Lyall, D. M., Mackay, D., Pidgeon, L. M., Cavanagh, J., Pell, J. P., O’Donovan, M., Escott-Price, V., Harrison, P. J., & Smith, D. J. (2018). Genome-wide analysis of self-reported risk-taking behaviour and cross-disorder genetic correlations in the UK Biobank cohort. Translational Psychiatry, 8. https://doi.org/10.1038/s41398-017-0079-1

This was co-authored by  Tünde Kilencz, a psychologist and research assistant at Semmelweis University, Department of Psychiatry and Psychotherapy in Budapest, Hungary.

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