Early Career Impact Awardee – Behavior Genetics Association
Dr. Emma Johnson’s research has contributed to our understanding of the genetic factors underlying substance use disorders, which continue to be a major public health concern and among the most frequent comorbidities with other mental and physical health conditions. After earning her PhD in Psychology – Behavioral, Psychiatric, and Statistical Genetics from the University of Colorado Boulder in 2017, she began her career in the Department of Psychiatry at Washington University School of Medicine in St Louis, Missouri where she is now an Assistant Professor. Through her use of large-scale genome-wide association studies (GWAS) of SUDs, she characterizes the genomic and biological underpinnings of SUDs, advances our understanding of the genetic similarities and distinctions between SUDs and substance use behaviors (e.g., cannabis use) and other relevant phenotypes (e.g., schizophrenia), and has enabled hundreds of follow-up studies using the publicly-available summary statistics that were generated from this body of work.
As PhD student, Dr. Johnson asked evolutionarily-informed questions about human behaviors and psychiatric disorders, such as whether genetic risk variants for schizophrenia have been under negative selection pressures over time. Using studies of autozygosity (alleles or chromosomal segments of DNA that are identical as a result of inheritance from a shared ancestor), she has shown that different classes of genetic variants (e.g., rare, recessive variants) contribute to complex traits. Recently, she has shown lower levels of autozygosity in younger samples than in older adults, supporting that overall levels of autozygosity are decreasing over generations in certain populations.
Dr. Johnson has advanced our understanding of the genetic relationships between SUDs and mental health conditions, including schizophrenia and suicide. For example, she has showed moderately large genetic correlations between suicide-related phenotypes – suicidal ideation, suicide attempt, and suicide death – and substance use disorders, genetic correlations that are similar in magnitude to those between suicide-related phenotypes and depression. With her NIDA-funded research, she has focused on the relationship between cannabis and psychosis; for example, she has shown that genetic risk for schizophrenia is robustly associated with cannabis-related psychosis-like experiences. Her work has led to multiple invitations to present at conferences like The American College of Neuropsychopharmacology, or community events like Research Connections hosted by the American Foundation for Suicide Prevention.
Ultimately, the goal of Dr. Johnson’s research is to improve diagnosis and treatments for psychiatric disorders, as well as to decrease stigma around these disorders. Dr. Johnson actively presents and teaches about her and others’ recent findings from psychiatric and behavioral genetics research with the hundreds of undergraduate students in her class each year. In this way, she hopes to increase the genetic literacy and empathy of the next generation of scholars.
