Irwin Waldman

My overarching interests are in developmental psychopathology and behavior genetics. In my lab we work at the intersection of psychology, statistics, and biology to understand the classification, causes, development, and biological underpinnings of psychopathology and relevant personality traits across the lifespan. Although we study psychopathology broadly, we also have a specific focus on understanding the causes, classification, and development of childhood disruptive disorders (i.e., ADHD, ODD, and Conduct Disorder [CD]) and externalizing behavior problems (e.g., aggression, psychopathic traits), as well as related personality / temperament traits (e.g., prosociality, Negative Emotionality), social cognitive mechanisms (e.g., perception of others’ intention cues), and neurocognitive functions. A major focus of my research centers on disentangling and characterizing the genetic and environmental influences that underlie these traits and disorders, as well as understanding how such factors combine to induce risk for psychopathology. These themes and representative projects are described below. The Structure and Classification of Psychopathology To address these issues, I use developmental behavior genetic methods (primarily twin study designs) in which the genetic and environmental influences that underlie such disorders and behavior problems can be disentangled and their magnitude can be quantified. I also use these methods to gain a better understanding of comorbidity, in particular the extent to which common genetic and environmental influences may account for the overlap within and among childhood externalizing and internalizing disorders, and the covariation of these disorders with temperament and personality traits. Quantitative Genetics In addition to conducting twin studies to estimate genetic and environmental influences, I use molecular genetic methods to search for specific genes that may account for the genetic influences on these disorders and traits. Historically, most of the genes we studied underlie various neurotransmitter systems, though recently we have begun examining neuropeptide genes such as the arginine vasopressin 1a receptor (AVPR1a) and oxytocin receptor gene (OXTR). We genotype multiple markers to capture genetic variation across the genes and use omnibus gene-based tests, thus increasing the likelihood of obtaining replicable associations with disorders and traits. We also are transitioning from examining associations with specific genes selected a priori to conducting gene-based tests of data from Genome Wide Association Scans (GWAS) of ADHD, Conduct Disorder, aggression, and psychopathic traits, as GWAS provides more comprehensive and unbiased tests of genetic associations. Within the context of behavioral and molecular genetic designs, we have also examined specific environmental influences at a number of different levels (e.g., pre- and peri-natal influences, parenting behavior, neighborhood characteristics), neurocognitive endophenotypes (e.g., measures of inattention and impulsivity), and social cognitive mechanisms (e.g., hostile perceptual biases, and deficits and biases in the processing of facial emotions) that may underlie externalizing disorders and the development of aggression and psychopathic traits. We also are using twin study designs and sophisticated statistical methods (e.g., Confirmatory Factor Analysis [CFA], Exploratory Structural Equation Modeling [ESEM], and Item Response Theory [IRT]) to test alternative models for the hierarchical dimensional structure of psychopathology. Finally, I've recently co-authored or edited several pieces focusing explicitly on replication issues in our field. Molecular Genetics Increasingly we use molecular genetic methods, particularly genome-wide association studies (GWAS), to search for specific genes and biological pathways that underlie these disorders and traits. We have been involved in large-scale GWAS of ADHD, ODD, Conduct Disorder, Bipolar Disorder, antisocial behavior, and the Externalizing spectrum. We are particularly interested in gene-based and pathway-based association tests, genetic correlations among disorders and relevant traits, understanding the biological meaning of associated genes, and uses of polygenic risk scores. Within the context of quantitative and molecular genetic designs, we also are interested in examining neurocognitive endophenotypes (e.g., lab measures of inattention and impulsivity) and social cognitive mechanisms (e.g., hostile perceptual biases, and deficits and biases in the processing of facial emotions) that may underlie externalizing disorders and other forms of psychopathology, and the development of aggression Statistical Methods We use a variety of sophisticated statistical methods (e.g., Confirmatory Factor Analysis [CFA], Exploratory Structural Equation Modeling [ESEM], and Item Response Theory [IRT]) to test alternative models for the hierarchical dimensional structure of psychopathology in general and externalizing in particular. In addition, we use meta-analytic methods and multivariate quantitative genetic analyses in our research. I've also co-authored or edited several pieces focusing explicitly on replication issues. Diversity and Inclusiveness We welcome lab members from diverse backgrounds. In an effort to reduce mental health disparities, we are also actively extending our studies and research findings in the above domains to examine sex differences and similarities and differences in underrepresented groups, such as individuals from non-European backgrounds. Thus, an interest in and commitment to diversity and inclusiveness is important. Waldman Lab Research Topics 1. Using Genome-Wide Data to Find Genes for Externalizing Psychopathology, including Attention Deficit Hyperactivity Disorder, Conduct Disorder, Aggression, Psychopathic Traits, and Antisocial Behavior 2. Tests of Specific Genes as Risk Factors for Externalizing Psychopathology a. Association of the Oxytocin Receptor gene with Autism, Aggression, and Social Behavior b. Finding Dopamine & Noradrenergic Genetic Risk Factors for ADHD 3. Meta-Analyses of Genetic and Environmental Influences on ADHD and Antisocial Behavior 4. Analyses of the Classification and Underlying Structure of Youth Psychiatric Disorders 5. Etiological Relation of Temperament and Personality with Youth Psychiatric Disorders 6. Neurocognitive and Social Cognitive Endophenotypes for ADHD and Aggression 7. Rigorous Tests of Direct Causal Environmental Influences on Child Psychopathology 8. Exploration of Issues Related to Replicability of Findings of Psychological Research Information for Prospective Students Graduate student applicants should have substantive interests in conducting research on the classification and underlying causes of personality and psychopathology. Specifically, a strong interest in disentangling and characterizing genetic and environmental influences on personality and psychopathology is key, as we use quantitative genetic and molecular genetic methods extensively in my lab. Our research thus integrates psychology, statistics, and biology. We also are actively seeking to extend our studies and research findings in these domains to underrepresented groups, such as individuals from non-European backgrounds, so an interest in and commitment to diversity is important. We use a variety of sophisticated statistical analytic methods on very large datasets, so a strong statistical background and keen interest in further developing one’s quantitative reasoning and skills is paramount. Graduate students in my lab are expected to contribute to ongoing research projects in the lab, as well as to develop their own research program under my mentorship. Applicants with the following characteristics will receive the strongest consideration: 1. A strong statistical background, as evidenced by having taken several statistics courses, and a strong interest in further developing one’s quantitative skills. 2. A strong coding background, with working knowledge of using R for generating statistical graphics and conducting various kinds of statistical analyses. Knowing Python also is helpful. 3. Having worked previously in a researcher’s lab for at least a year. Being a coauthor on publications and conference presentations also is highly desirable. 4. Completing an Honor’s thesis also is advantageous. 5. Some post-undergraduate research experience is typical. 6. Some familiarity with behavior genetic (e.g., twin or adoption study) and molecular genetic (e.g., Genome Wide Association Studies) methods / findings 7. Substantive familiarity with personality and psychopathology research

a. Demontis, D., Walters, G.B., Athanasiadis, G. et al. Genome-wide analyses of ADHD identify 27 risk loci, refine the genetic architecture and implicate several cognitive domains. Nat Genet 55, 198–208 (2023). https://doi.org/10.1038/s41588-022-01285-8 h. Waszczuk, M.A., Jonas, K.G., Bornovalova, M. ...Waldman ID. (2023). Dimensional and transdiagnostic phenotypes in psychiatric genome-wide association studies. Mol Psychiatry. https://doi.org/10.1038/s41380-023-02142-8 a. Waldman, I. D., King, C. D., Poore, H. E., Luningham, J. M., Zinbarg, R. M., Krueger, R. F., Markon, K. E., Bornovalova, M., Chmielewski, M., Conway, C., Dretsch, M., Eaton, N. R., Forbes, M. K., Forbush, K., Naragon-Gainey, K., Greene, A. L., Haltigan, J. D., Ivanova, M., Joyner, K., … Zald, D. (2023). Recommendations