About

Professor Sarah Thomas is part of the Adolescent Mental Health Collaborative, a research group that includes researchers and scientist-practitioners in the fields of psychology and psychiatry. The collaborative is dedicated to improving the mental health of youth through coordinated research, treatment, and training. The team has extensive experience and expertise in child and adolescent mental health and developmentally appropriate psychological education, reflecting Professor Thomas's commitment to advancing understanding and interventions in adolescent mental health.

Research topics

• Psychiatry
• Psychology
• Medicine
• Clinical psychology
• Medical emergency
• Psychotherapist

Selected publications

• The role of subcortical brain tissue iron as an indicator of dopamine neurophysiology in adolescent cannabis use

  PsyArXiv (OSF Preprints) · 2026-05-08

  preprintOpen access

  Approximately 10-20% of U.S. adolescents report past-year cannabis use (CU). Although regular CU beginning in adolescence is expected to blunt dopamine-related neurophysiology, this hypothesis has not been tested in adolescents due to methodological limitations. However, neurophysiology contributing to dopamine can be noninvasively indexed via subcortical tissue iron measured with magnetic resonance imaging (MRI). We examined adolescent CU quantity, frequency, and problems in relation to tissue iron in regions with high dopamine activity, hypothesizing that greater CU would be linked to less tissue iron. Adolescents (n=81; 64.2% female) aged 14-17 reporting either fewer than 5 lifetime cannabis episodes (n=47) or more than 11 episodes (n=34), with limited alcohol and nicotine use and no other illicit substance use, completed substance use assessments and an MRI. We calculated the inverse of the normalized T2* measurement (1/nT2*; lower values indicate less tissue iron) from resting-state functional scans by assessing relative T2* decay. 1/nT2* was estimated using subcortical masks for hypothesized regions. Lower 1/nT2* signal was associated with increased daily concentrate hits (b = -0.01, p < 0.001), cannabis hours high (b = -0.01, p = 0.016), CU frequency (b = -0.01, p = 0.01), and cannabis use disorder (CUD) severity (b = -0.01, p = 0.003). Post-hoc analyses highlighted the VTA as a key region. Results align with reduced dopamine-related neurophysiology associated with CU in adult and animal samples, and have implications for understanding adolescent CUD development. Measuring 1/nT2* offers an innovative, non-invasive method to index neurobiological alterations in adolescent CU.

  Publisher

• The role of subcortical brain tissue iron as an indicator of dopamine neurophysiology in adolescent cannabis use

  2026-05-13

  articleOpen access1st authorCorresponding

  Approximately 10-20% of U.S. adolescents report past-year cannabis use (CU). Although regular CU beginning in adolescence is expected to blunt dopamine-related neurophysiology, this hypothesis has not been tested in adolescents due to methodological limitations. However, neurophysiology contributing to dopamine can be noninvasively indexed via subcortical tissue iron measured with magnetic resonance imaging (MRI). We examined adolescent CU quantity, frequency, and problems in relation to tissue iron in regions with high dopamine activity, hypothesizing that greater CU would be linked to less tissue iron. Adolescents (n=81; 64.2% female) aged 14-17 reporting either fewer than 5 lifetime cannabis episodes (n=47) or more than 11 episodes (n=34), with limited alcohol and nicotine use and no other illicit substance use, completed substance use assessments and an MRI. We calculated the inverse of the normalized T2* measurement (1/nT2*; lower values indicate less tissue iron) from resting-state functional scans by assessing relative T2* decay. 1/nT2* was estimated using subcortical masks for hypothesized regions. Lower 1/nT2* signal was associated with increased daily concentrate hits (b = -0.01, p < 0.001), cannabis hours high (b = -0.01, p = 0.016), CU frequency (b = -0.01, p = 0.01), and cannabis use disorder (CUD) severity (b = -0.01, p = 0.003). Post-hoc analyses highlighted the VTA as a key region. Results align with reduced dopamine-related neurophysiology associated with CU in adult and animal samples, and have implications for understanding adolescent CUD development. Measuring 1/nT2* offers an innovative, non-invasive method to index neurobiological alterations in adolescent CU.

  PublisherDOI

• The role of subcortical brain tissue iron as an indicator of dopamine neurophysiology in adolescent cannabis use

  2025-10-28

  preprintOpen access1st authorCorresponding

  Approximately 10-20% of U.S. adolescents report past-year cannabis use (CU). Although regular CU beginning in adolescence is expected to blunt dopamine-related neurophysiology, this hypothesis has not been tested in adolescents due to methodological limitations. However, neurophysiology contributing to dopamine can be noninvasively indexed via subcortical tissue iron measured with magnetic resonance imaging (MRI). We examined adolescent CU quantity, frequency, and problems in relation to tissue iron in regions with high dopamine activity, hypothesizing that greater CU would be linked to less tissue iron. Adolescents (n=81; 64.2% female) aged 14-17 reporting either fewer than 5 lifetime cannabis episodes (n=47) or more than 11 episodes (n=34), with limited alcohol and nicotine use and no other illicit substance use, completed substance use assessments and an MRI. We calculated the inverse of the normalized T2* measurement (1/nT2*; lower values indicate less tissue iron) from resting-state functional scans by assessing relative T2* decay. 1/nT2* was estimated using subcortical masks for hypothesized regions. Lower 1/nT2* signal was associated with increased daily concentrate hits (b = -0.01, p < 0.001), cannabis hours high (b = -0.01, p = 0.016), CU frequency (b = -0.01, p = 0.01), and cannabis use disorder (CUD) severity (b = -0.01, p = 0.003). Post-hoc analyses highlighted the VTA as a key region. Results align with reduced dopamine-related neurophysiology associated with CU in adult and animal samples, and have implications for understanding adolescent CUD development. Measuring 1/nT2* offers an innovative, non-invasive method to index neurobiological alterations in adolescent CU.

  PublisherDOI

• Investigating Substance Use as a Coping Strategy Among Adolescent Psychiatric Inpatients: A Comparative Analysis Before and During the COVID-19 Pandemic

  Child Psychiatry & Human Development · 2024-07-04 · 4 citations

  articleOpen access1st authorCorresponding
  PublisherOA PDFDOI

• Cannabis Vaping Is Associated With Past 30-Day Suicide Attempts and Suicidal Ideation Among Adolescents in a Psychiatric Inpatient Setting

  JAACAP Open · 2024-05-09 · 2 citations

  articleOpen access1st authorCorresponding

  Objective: Increasing evidence links adolescent cannabis use (CU) to suicidal thoughts and behaviors.CU may be associated with both developing and self-medicating psychiatric symptoms.Although relatively new, cannabis vaping is increasing among adolescents.This chart review investigation evaluated the association between cannabis vaping and suicidal thoughts and behaviors among adolescents experiencing acute psychiatric symptomatology.Method: The sample included 470 adolescents (ages 11-18; 64% biological female) admitted to an inpatient psychiatric hospital between 2021 and 2023.Adolescents completed an assessment battery measuring CU, psychiatric symptoms, and suicidal thoughts and behaviors.Separate regressions tested links between cannabis vaping and 2 outcomes-past 30-day suicide attempt and suicidal ideation (SI)-controlling for age and biological sex.Results: In this sample, 26.8% reported past 30-day suicide attempts; 44.3% endorsed ever using cannabis, and 31.5% reported past 30-day CU.Of adolescents who ever used cannabis, 30.8% reported their most frequent method was vaping.Vaping as the most frequent cannabis method was associated with past 30-day suicide attempts (adjusted odds ratio 2.38, p .002)and greater SI (b 8.71, p .020).The association remained significant for suicide attempts, but only marginally significant for SI (p .087),after controlling for depressive symptoms, impulse control, psychosocial impairment, and past 30-day substance use.Conclusion: Vaping as the most frequent method of CU was significantly associated with suicide attempts and SI.Because data are cross-sectional, causality cannot be inferred.Nonetheless, cannabis vaping is important to assess among adolescents with acute psychiatric concerns because it may place them at higher risk for suicidal thoughts and attempts.Plain language summary: Vaping can deliver higher potency cannabis than other routes of administration, and adolescents are increasingly vaping to consume cannabis.This chart review study of 470 adolescents admitted to an inpatient psychiatric hospital found that vaping is the most frequent way of using cannabis.Vaping was associated with a greater likelihood of a past 30-day suicide attempt and worse suicidal thoughts compared to adolescents who never used or who smoked cannabis as their primary method.Adults should be aware of how adolescents are consuming cannabis, especially if it is occurring in the context of psychiatric disorders.

  PublisherOA PDFDOI

• Correlates of Menarcheal Age in a Psychiatric Sample of Adolescents

  The Journal of Nervous and Mental Disease · 2024-01-30 · 3 citations

  articleOpen accessCorresponding

  ABSTRACT: Early pubertal timing is associated with more adverse childhood experiences (ACEs) and increased risk for psychopathology during adolescence. However, most work to date has used community or epidemiological samples, and it remains unclear whether these associations persist in acute clinical samples. The present study examined associations between age at menarche and ACEs, psychiatric symptoms, and emotion regulation difficulties in a sample of N = 140 adolescents on a psychiatric inpatient unit. Youth with early menarche reported higher levels of depressive symptoms, more severe suicidal ideation, and greater difficulty with emotion regulation than youth with normative age at menarche. There was a marginal effect of youth with early menarche reporting more ACEs and more anxiety symptoms. These results suggest menarcheal age, and ACEs may be useful risk factors to assess in inpatient settings to predict risk for more severe outcomes, and future research on pubertal timing in high acuity settings is warranted.

  PublisherOA PDFDOI

• Links between parental monitoring and parent–adolescent conflict: A multimodal test of bidirectional relations.

  Journal of Family Psychology · 2024-05-16 · 1 citations

  articleOpen access1st authorCorresponding

  = 65) interacted for 5 min about an adolescent-identified conflict topic. Different beliefs about daily life topics related to parental knowledge: parents' reports of greater different beliefs about daily life topics predicted less knowledge of adolescents' activities/whereabouts, solicitation, and disclosure, for both parent and adolescent reports of these domains. For adolescents, greater different beliefs related to less solicitation and disclosure. Only adolescent reports of parental knowledge, solicitation, and disclosure predicted attachment-related behaviors both dyad members displayed during the conflict discussion task. Findings reveal links between parental knowledge of adolescents' activities and conflict processes and demonstrate dyadic interdependence between parental knowledge of adolescents' activities and conflict processes. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

  PublisherDOI

• Psychometric properties of the family assessment task parental monitoring scenario among adolescents receiving substance use treatment

  Journal of Substance Use and Addiction Treatment · 2023-12-05 · 1 citations

  articleOpen accessCorresponding
  PublisherOA PDFDOI

• Resting state network connectivity is associated with cognitive flexibility performance in youth in the Adolescent Brain Cognitive Development Study

  Neuropsychologia · 2023-10-27 · 15 citations

  articleOpen access1st authorCorresponding
  PublisherOA PDFDOI

• Leveraging Parent–Youth Interactions to Measure and Analyze Emotion Regulation

  Cambridge University Press eBooks · 2023-11-30

  book-chapter1st authorCorresponding

  Developmental theories propose that children learn emotion regulation through dynamic interactions with their parents over time. Emotion regulation is transmitted intergenerationally through environmental and genetic pathways, yet both parents and children evoke regulatory capacities from each other. Further, these interactive effects iterate on a micro -level day by day, as well as on a longer time scale, influenced by factors like parenting style and dyadic conflict. Thus, dyadic parent–child emotion regulation is a bidirectional developmental process requiring careful study design, measurement, and analysis. Yet there are fewer research studies on these dynamic processes than one would expect, perhaps due to the aforementioned complexity. In this chapter, we provide a brief theoretical background on interactive emotion regulation between parent–child dyads, review example studies that have addressed these processes, identify conceptual and methodological barriers to conducting this research, and provide resources for researchers. Finally, we highlight the Actor–Partner Interdependence Model to derive interactive and bidirectional inferences into parent–youth emotion regulation.

  PublisherDOI

Recent grants

• Cognitive flexibility and reward motivation in adolescent cannabis use: An investigation of neurobehavioral mechanisms and intrinsic resting state connectivity.

  NIH · $787k · 2021–2025

• Experimentally Testing the Effect of Parent-Adolescent Conflict on HIV Risk

  NIH · $104k · 2012–2015

Frequent coauthors

• Luís A. Moreno

  92 shared

• Laura Censi

  87 shared

• Enrique G. Artero

  University of Almería

  87 shared

• Sabine Dietrich

  Medical University of Vienna

  86 shared

• Stamatoula Tsikrika

  86 shared

• S Castello

  86 shared

• Nico Rizzo

  Universidad de Zaragoza

  86 shared

• Noemi Bevilacqua

  86 shared

Awards & honors

• BBRF/NARSAD Young Investigator Award