Irwin WaldmanProfessor

I am a clinical psychologist and behavior geneticist and did my undergraduate degree in Human Development and Family Studies at Cornell University, graduating in 1982, then attended graduate school at the University of Waterloo in Ontario, Canada earning my Ph.D. in clinical psychology in 1988. Following my year-long clinical internship at the Lafayette Clinic in Detroit (1987-88), I completed a three-year Postdoctoral Fellowship in Behavioral Genetics at the University of Minnesota. I have been a faculty member in the Psychology Department at Emory University since the fall of 1991. I was President-Elect / President of the Behavior Genetics Association from 2010-11 and am an Associate Editor of the journal, Behavior Genetics. I have been on the editorial boards of four other journals (Journal of Abnormal Psychology, Clinical Psychological Science, Journal of Abnormal Child Psychology, and Development and Psychopathology

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
   1. Association of the Oxytocin Receptor gene with Autism, Aggression, and Social Behavior
   2. 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

•  PSYC 190: Freshman Seminar in Psychology – The Nature of Evidence

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   PSYC 351: The Nature of Evidence (Maymester)

  · PSYC 352: The Genetics of Human Behavior

   

• PSYC 385R: American Films of the 1970s: Individualist versus Collectivist Identities (Academic year and Maymester)

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   PSYC 561: Multiple Regression and the General Linear Model

  · PSYC 770R: Latent Variable Model

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   PSYC 770R: Statistical Graphic

A complete list of my publications can be found on my Google Scholar page.

REPRESENTATIVE PUBLICATIONS

Classification, Structure, and Validity of Externalizing and Broad Psychopathology

a. Lahey, B. B., Krueger, R. F., Rathouz, P. J., Waldman, I. D., & Zald, D. H. (2017). A hierarchical causal

taxonomy of psychopathology across the life span. Psychological Bulletin, 143, 142-186.

b. Kotov R, Krueger RF, Watson D, Achenbach TM, Althoff RR, Bagby RM, et al. (2017). The Hierarchical Taxonomy of Psychopathology (HiTOP): A dimensional alternative to traditional nosologies. Journal of Abnormal Psychology, 126, 454–77.

c. Krueger RF, Hobbs KA, Conway CC, Dick DM, Dretsch MN, Eaton NR, et al. (2021). Validity and utility of Hierarchical Taxonomy of Psychopathology (HiTOP): II. Externalizing superspectrum. World Psychiatry, 20, 171–93.

d. Kotov R, Krueger RF, Watson D, Cicero DC, Conway CC, DeYoung CG, et al. (2021). The Hierarchical Taxonomy of Psychopathology (HiTOP): A Quantitative Nosology Based on Consensus of Evidence. Annual Review of Clinical Psychology, 17, 83–108.

e. Watson D, Levin-Aspenson HF, Waszczuk MA, Conway CC, Dalgleish T, Dretsch MN, et al

(2022). Validity and utility of Hierarchical Taxonomy of Psychopathology (HiTOP): III. Emotional dysfunction superspectrum. World Psychiatry, 21(1), 26-54. doi: 10.1002/wps.20943. PMID: 35015357; PMCID: PMC8751579.

f. Waldman ID, Poore HE, Luningham JM, Yang J. (2020). Testing structural models of psychopathology at the genomic level. World Psychiatry,19, 350–9.

Classification and Underlying Structure of Youth Psychopathology

a. Lahey, B. B., Rathouz, P. J., Applegate, B., Van Hulle, C. A., Garriock, H. A., Urbano, R. C.,

Chapman, D. A., Krueger, R. F., & Waldman, I. D. (2008). Testing structural models of DSM-IV symptoms of common forms of child and adolescent psychopathology. Journal of Abnormal Child Psychology, 36, 187-206.

b. Lahey, B.B., Applegate, B., McBurnett, K., Biederman, J., Greenhill, L., Hynd, G.W., Barkley, R.A., Newcorn, J., Jensen, P., Richters, J., Garfinkel, B., Kerdyk, L., Frick, P.J., Ollendick, T., Perez, D., Hart, E.L., Waldman, I., & Shaffer, D. (1994). DSM-IV field trials for attention-deficit / hyperactivity disorder in children and adolescents. American Journal of Psychiatry, 151,1673-1685.

c. Lahey, B.B., Applegate, B., Barkley, R.A., Garfinkel, B., McBurnett, K.,Kerdyk, L., Greenhill, L., Hynd, G.W., Frick, P.J., Newcorn, J., Biederman, J., Ollendick, T., Hart, E.L., Perez, D., Waldman, I., & Shaffer, D. (1994). DSM-IV field trials for oppositional defiant disorder and conduct disorder in children and adolescents. American Journal of Psychiatry, 151, 1163-1171.

Statistical issues in analyses of the structure and classification of psychopathology

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 for Adjudicating Among Alternative Structural Models of Psychopathology. Clinical Psychological Science, 11(4), 616–640. https://doi.org/10.1177/21677026221144256

b. Watts AL, Poore HE, Waldman ID. (2019). Riskier Tests of the Validity of the Bifactor Model of

Psychopathology. Clinical Psychological Science, 7,1285-1303.

c. Waldman, I. D. (2005). Statistical Approaches to Complex Phenotypes: Evaluating Neuropsychological Endophenotypes for Attention-Deficit/Hyperactivity Disorder,

Biological Psychiatry, 57, 1347-1356.

 Quantitative Genetic Studies of Youth Psychopathology

a. Waldman I.D., Rhee S.H., Levy F., Hay D.A.. (2021). Causes of the overlap among symptoms of Attention Deficit Hyperactivity Disorder, Oppositional Defiant Disorder, and Conduct Disorder. In Attention, genes, and ADHD, Florence Levy & David A. Hay (Eds.), pp.115-138, Psychology Press: London.

b. Singh AL, Waldman ID. (2010). The etiology of associations between negative emotionality and childhood externalizing disorders. J Abnormal Psychology, 119, 376–88.

c. Waldman ID, Poore HE, van Hulle C, Rathouz PJ, Lahey BB. (2016). External validity of a hierarchical dimensional model of child and adolescent psychopathology: Tests using confirmatory factor analyses and multivariate behavior genetic analyses. Journal of Abnormal Psychology, 125, 1053–66.

d. Rhee SH, Lahey BB, Waldman ID. (2015). Comorbidity Among Dimensions of Childhood Psychopathology: Converging Evidence from Behavior Genetics. Child Development Perspectives, 9, 26–31.

e. Poore, H. E., Watts, A. L., Friedman, H. P., & Waldman, I. D. (2022). A broad internalizing dimension accounts for the genetic associations between personality and individual internalizing disorders. Journal of Psychopathology and Clinical Science, 131(8), 857–867. https://doi.org/10.1037/abn0000782

Genome-wide Association Studies (GWAS) of Externalizing Psychopathology

 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

b. Demontis D, Walters RK, Martin J, Mattheisen M, Als TD, Agerbo E, et al. (2019). Discovery of the first genome-wide significant risk loci for attention deficit/hyperactivity disorder. Nature Genetics, 51, 63–75.

c. Demontis D, Walters RK, Rajagopal VM, Waldman ID, Grove J, Als TD, et al. (2021). Risk variants and polygenic architecture of disruptive behavior disorders in the context of attention-deficit/hyperactivity disorder. Nature Communications,12, 1-12.

d. Linnér RK, Mallard TT, Barr PB, Sanchez-Roige S, Madole JW, Driver MN, et al. (2021). Multivariate genomic analysis of 1.5 million people identifies genetic associations with traits related to self-regulation and addiction. Nature Neuroscience, 24, 1367-1376.

e. Tielbeek JJ, Johansson A, Polderman TJC, et al. Genome-Wide Association Studies of a Broad Spectrum of Antisocial Behavior. JAMA Psychiatry. 2017;74(12):1242–1250. doi:10.1001/jamapsychiatry.2017.3069

g. Mullins, N., Forstner, A.J., O’Connell, K.S. et al. Genome-wide association study of more than 40,000 bipolar disorder cases provides new insights into the underlying biology. Nat Genet 53, 817–829 (2021). https://doi.org/10.1038/s41588-021-00857-4

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

Meta-Analyses of Genetic and Environmental Influences on Psychopathology

a. Gizer, I.R., Ficks, C.A., & Waldman, I.D. (2009). Candidate gene studies of ADHD: a meta-analytic review. Human Genetics, 126, 51-90.

b. Rhee, S.H. & Waldman, I.D. (2002). Genetic and environmental influences on antisocial behavior: A meta-analysis of twin and adoption studies. Psychological Bulletin, 128, 490-529.

c. Ficks, C.A. & Waldman, I.D. (2014). Candidate Genes for Aggression and Antisocial Behavior: A Meta-analysis of Association Studies of the 5HTTLPR and MAOA-uVNTR. Behavior Genetics, 44, 427-444.

d. Poore HE, Waldman ID. (2020). The Association of Oxytocin Receptor Gene (OXTR) Polymorphisms with Antisocial Behavior: A Meta-analysis. Behavior Genetics, 50, 161–73.

e. LoParo, D., Waldman, I.D. (2015). The oxytocin receptor gene (OXTR) is associated with autism spectrum disorder: a meta-analysis. Mol Psychiatry 20, 640–646. https://doi.org/10.1038/mp.2014.77