Molecular genetics in psychology and personality neuroscience: On candidate genes, genome wide scans, and new research strategies.

Despite the substantial heritability estimates for psychological traits, their precise genetic foundation from a molecular perspective remains elusive. We summarize findings and advances from more than twenty years of research into the molecular genetics of personality and other psychological traits. We describe how the candidate gene approach has - despite its appealing theoretical foundations - often (but not always) failed to point towards replicable associations between genetic polymorphisms and behavioral traits. The genome wide analysis approach on the contrary has become more fruitful in recent years and pointed towards reliable genetic associations. Results from genome wide scan studies (GWAS) are currently leveraged to explore gene-behavior associations through genetic correlation and polygenic score prediction which are important steps towards a precision medicine where treatment options are tailored to a patient's individual biology. But it is also true that future work needs to take a closer look at GWAS findings to link the growing list of statistical associations to biopsychological theory. We argue that research strategies from the candidate gene approach can be used to address these issues - given that necessary precautions are taken to avoid the problem of false-positive associations.