Assistant Professor of Psychology
Dr. Schaefer received his Ph.D in Clinical Psychology from Duke University and completed his postdoc at the University of Minnesota, where he was awarded a K01 Career Development Award from NIDA.
Dr. Schaefer has two primary research objectives. The first is improving scientific understanding of the relationship between environmental exposures (e.g., socioeconomic disadvantage, environmental toxicants, victimization, substance use) and psychopathology, thereby generating actionable insights for interventionists, policymakers, and consumers. Work in line with this objective is explicitly multi-modal and multi-disciplinary, combining theory and methods from developmental science, clinical psychology, behavioral genetics, and psychiatric epidemiology. Specifically, it seeks to (1) determine whether associations between environmental factors and mental health represent causal processes or statistical confounding using twin and longitudinal methods, as well as (2) identify modifiable mechanisms that might drive causal effects.
Dr. Schaefer's second research objective is to contribute to the destigmatization of mental health problems and wider uptake of evidence-based treatments. He has written several research and popular science articles showing that if people are followed long enough while being assessed frequently for mental disorders, almost everyone will accrue at least one psychiatric diagnosis at some point.
Dr. Schaefer will be recruiting a grad student, postdoc, and lab manager for 2024. He is particularly excited to work with folks interested in the (1) environmental determinants of mental health, (2) behavioral genetics, and (3) using technology to improve the measurement of both mental health and people's social and physical environments.
24. Zellers, S.M., Alexander, J., Ellingson, J.M., Schaefer, J.D., Corley, R.P., Iacono, W., Hewitt, J.K., Hopfer, C.J., McGue, M.K., Vrieze, S. (in press) Limited psychological and social effects of lifetime cannabis use frequency: Evidence from a 30-year community study of 4,078 twins. Journal of Psychopathology and Clinical Science.
23. Padrutt, E.R., Harper, J., Schaefer, J.D., Nelson, K.M., McGue, M., Iacono, W.G., Wilson, S. (in press) Pubertal timing and adolescent outcomes: Investigating explanations for associations with a genetically informed design. Journal of Child Psychology and Psychiatry.
22. Schaefer, J.D., Nelson, K., Wilson, S. (2023) The effects of adolescent cannabis use on psychosocial functioning: A critical review of the evidence. Child and Adolescent Psychiatric Clinics of North America, 32(6), 43-55. doi: 10.1016/j.chc.2022.06.003
21. Schaefer, J.D., Cheng, T., Dunn, E.C. (2022). Sensitive periods in development and risk for psychiatric disorders and related endpoints: a systematic review of child maltreatment findings. The Lancet Psychiatry, 9(12), 978-991. doi: 10.1016/S2215-0366(22)00362-5
20. Deak, J., Clark, D., Liu, M., Schaefer, J.D., Jang, S., Durbin, C., Iacono, W., McGue, M., Vrieze, S., Hicks, B. (2022). Alcohol and nicotine polygenic scores are associated with the development of alcohol and nicotine use problems from adolescence through young adulthood. Addiction, 117, 1117-1127. doi: 10.1111/add.15697
19. Assari, S. & Schaefer, J.D. (2021) Parental educational attainment and frequency of marijuana use in youth: Hispanics’ diminished returns. Journal of Educational and Cultural Studies, 5(6), 47-60.
18. Schaefer, J.D., Jang, S., Clark, D.A., Deak, J.D., Hicks, B.M., Iacono, W.G., Liu, M., McGue, M., Vrieze, S., Wilson, S. (2021) Associations between polygenic risk of substance use and use disorder and alcohol, cannabis, and nicotine use in adolescence and young adulthood in a
longitudinal twin study. Psychological Medicine, 1-11. doi:10.1017/S0033291721004116
17. Polusny, M.A., Marquadt, C.A., Campbell, E.H., Filetti, C.R., Noel, V.V., Disner, S.G., Schaefer, J.D., Davenport, N., Lissek, S., Noorbaloochi, S., Sponheim, S.R., Erbes, C.R. (in press). Advancing Research on Mechanisms of Resilience (ARMOR) longitudinal cohort study of new military recruits: results from a feasibility pilot study. Research in Human Development, 18(3), 212-229. doi: 10.1080/15427609.2021.1964898
16. Hicks, B.M., Clark, D.A., Deak, J.D., Schaefer, J.D., Liu, M., Jang, S., Durbin, C.E., Johnson, W., Wilson, S., Iacono, W.G., McGue, M., Vrieze, S.I. (2021). Polygenic scores for smoking and educational attainment have independent influences on academic success and adjustment in adolescence and educational attainment in adulthood. PLOS ONE, 16(8):e0255348. doi: 10.1371/journal.pone.0255348
15. Schaefer, J.D., Jang, S., Vrieze, S., Iacono, W.G., McGue, M., Wilson, S. (2021). Adolescent cannabis use and adult psychoticism: A longitudinal co-twin control analysis using data from two cohorts. Journal of Abnormal Psychology, 130(7), 691-701. doi: 10.1037/abn0000701
Interviews: Mind & Matter (December, 2021)
14. Reuben, A., Arseneault, L., Beddows, A., Beevers, S.D., Caspi, A., Moffitt, T.E., Ambler, A.P., Latham, R.M., Newbury, J.B., Odgers, C.L., Schaefer, J.D., Fisher, H.L. (2021). Air pollution exposure in childhood and adolescence and psychopathology at the transition to adulthood. JAMA Network Open, 4(4):e217508. doi:10.1001/jamanetworkopen.2021.7508 Selected news coverage: U.S. News, The Guardian, HealthDay, ScienceDaily, Popular Science, Earth.com, Daily Express, Futurity
13. Schaefer, J.D., Hamdi, N.R., Malone, S., Vrieze, S., Wilson, McGue, M., Iacono, W.G. (2021). Associations between adolescent cannabis use and young-adult functioning in three longitudinal twin studies. Proceedings of the National Academy of Sciences of the United States of America, 118(14), e2013180118. doi:10.1073/pnas.2013180118 Selected news coverage: APA’s Monitor on Psychology, U.S. News, Politico, Star Tribune, HealthDay, Cosmos, Healio, MN Daily, Star Tribune, Jamaica Observer, Ganjapreneur Interviews: Minnesota Public Radio – All Things Considered (April, 2021), “Researcher” App (July, 2022)
12. Hicks, B.M., Clark, D.A., Deak, J.D., Liu, M., Durbin, E., Schaefer, J.D., Wilson, S., Iacono, W.G., McGue, M., Vrieze, S.I. (2021). Polygenic score for smoking is associated with externalizing psychopathology and disinhibited personality traits but not internalizing psychopathology in adolescence. Clinical Psychological Science, 9(6), 1205-1213. doi: 10.1177/21677026211002117
11. Schaefer, J.D. (2021) Enduring mental health: The high lifetime prevalence of psychiatric disorder and emerging science of persistent mental wellness. Journal of the American Academy of Child and Adolescent Psychiatry, 60(8), 955-957. doi: 10.1016/j.jaac.2021.01.004
10. Weissman, D.G., Bitran, D., Miller, A.B., Schaefer, J.D., Sheridan, M.A., McLaughlin, K.A. (2019). Difficulties with emotion regulation as a transdiagnostic mechanism linking child maltreatment with the emergence of psychopathology. Development and Psychopathology, 31(3), 899-915. doi: 10.1017/S0954579419000348
9. *Reuben, A., *Schaefer, J.D., Moffitt, T.E., Belsky, D.W., Broadbent, J., Harrington, H., Houts, R., Ramrakha, S., Poulton, R., Caspi, A. (2019). Association of childhood lead exposure with adult personality traits and lifelong mental health. JAMA Psychiatry, 76(4), 418-425. doi: 10.1001/jamapsychiatry.2018.4192
Selected news coverage: U.S. News, Tech Times, Science Daily, Quartz, JAMA Network News
8. Schaefer, J.D. (2018). Use of hierarchical measures of psychopathology to capture the long (and wide) shadow of early deprivation in the Bucharest Early Intervention Project analysis. JAMA Psychiatry, 75(11), 1101-1102. doi:10.1001/jamapsychiatry.2018.2215 Selected news coverage: Reuters, Mad in America
7. Schaefer, J.D., Moffitt, T.E., Arseneault, L., Danese, A., Fisher, H.L., Houts, R., Sheridan, M. A., Wertz, J., Caspi, A. (2018). Adolescent victimization and early-adult psychopathology: Approaching causal inference using a longitudinal twin study to rule out alternative non-causal explanations. Clinical Psychological Science, 6(3), 352-371. doi: 10.1177/2167702617741381
Selected news coverage: APS Observations
6. Belsky, D.W., Moffitt, T.E., Cohen, A.A., Corcoran, D.L., Levine, M.E., Prinz, J., Schaefer, J.D., Sugden, K., Williams, B., Poulton, R., Caspi, A. (2018). Eleven telomere, epigenetic clock, and biomarker-composite quantifications of biological aging: Do they measure the same thing? American Journal of Epidemiology, 187(6), 1220-1230. doi: 10.1093/aje/kwx346
Selected news coverage: Herald-Tribune, The Verge Designated by the American Journal of Epidemiology as the “2018 Article of the Year”
5. *Schaefer, J.D., *Scult, M.A., Caspi, A., Belsky, D.W., Hariri, A.R., Harrington, M., Houts, R., Ramrakha, S. Poulton, R., Moffitt, T.E. (2017). Is low cognitive functioning a predictor or consequence of major depressive disorder? A test in two longitudinal birth cohorts. Development and Psychopathology, 1-15. doi: 10.1017/S095457941700164X
4. Schaefer, J.D., Caspi, A., Belsky, D.W., Harrington, H., Houts, R., Horwood, J., Hussong, A., Ramrakha, S., Poulton, R., Moffitt, T.E. (2017). Enduring mental health: prevalence and prediction. Journal of Abnormal Psychology, 126(2), 212-224. doi: 10.1037/abn0000232
Selected news coverage: Science News, Psychology Today, Weekendavisen, Huffington Post, New York Post, Teen Vogue, Elite Daily
Interviews: Think. Act. Be. (Podcast, Seth Gillihan, Ph.D) (May 2021), Who cares? What’s the Point? (Podcast, Sarb Johal, Ph.D) (August, 2017), NewsTalk770 (Radio CHQR) (February, 2017)
Highlighted by Science News as one of the most important contributions to understanding “The Science of Us” in the past 100 years
3. Belsky, D.W., Caspi, A., Houts, R., Cohen, H., Corcoran, D., Danese, A., Harrington, H., Israel, S., Levine, M., Schaefer, J. D., Sugden, K., Williams, B., Yashin, A., Poulton, R., Moffitt, T. E. (2015). Quantification of biological aging in young adults. Proceedings of the National Academy of Sciences, 112(30): E4104-10. doi: 10.1073/pnas.1506264112
Selected news coverage: The Wall Street Journal, The Washington Post, TIME, The Guardian, The Onion Elected by Science News as the 4th most important science paper in 2015 (behind Pluto, gene editing, and a new hominid).
2. Schaefer, J.D., Caspi, A., Belsky, D., Harrington, H., Houts, R., Israel, S., Levine, M., Sugden, K., Williams, B., Poulton, R., Moffitt, T. E. (2015). Early-life intelligence predicts midlife biological age. The Journal of Gerontology: Psychological Sciences, 1-8. doi: 10.1093/geronb/gbv035.
Selected news coverage: Psychology Today
1. Schaefer, J., Giangrande, E., Weinberger, D.R., Dickinson, D. (2013). The global cognitive impairment in schizophrenia: Consistent over decades and around the world. Schizophrenia Research, 150(1): 42-50. doi: 10.1016/j.schres.2013.07.009
Selected news coverage: medwireNews Received certificate from journal for being 1 of the 5 most highly cited papers published in Schizophrenia Research (December, 2016)
2022 - NIDA T32 Postdoctoral Fellowship in Genetic & Neurobehavioral Mechanisms of Addiction
2020 - NIMH T32 Postdoctoral Fellowship in Developmental Psychopathology
2020 - American Psychopathological Association (APPA) Travel Award
2018 - American Psychopathological Association (APPA) Poster Award
2017 - University Scholars Program Travel Award
2016 - Keohane Distinguished Visiting Professorship Graduate Student Award
2016 - NICHD T32 Predoctoral Fellowship in Developmental Science
2016 - Graduate School Conference Travel Award
2014 - International Society for Intelligence Research (ISIR) Travel Fellowship
2014 - Shaping the Developing Brain: From Prenatal to Early Childhood Travel Fellowship
2014 - University Scholars Program Travel Award
2014 - Claire Hamilton Graduate Student Conference Travel Award
2014 - NIA T32 Predoctoral Fellowship in the Demography of Aging
2014 - Curran & Bauer Analytics Student Tuition Scholarship
2013 - University Scholars Program Fellowship
2013 - James B. Duke Fellowship
2011 - NIH Intramural Research Training Award (IRTA)
2011 - Election to Phi Beta Kappa
2010 - Swarthmore Joel Dean Summer Research Fellowship