Behrang Mahjani

Behrang Mahjani

Research Specialist

We study developmental origins and trajectories of neuropsychiatric disorders, including psychiatric-somatic comorbidity (lower urinary tract symptoms), and how genetic profiles influence long-term tr

Visiting address: D4:53, Eugeniavägen 3, 17164 Stockholm
Postal address: K1 Molekylär medicin och kirurgi, K1 MMK Urologi, 171 76 Stockholm
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About me

  • Our lab investigates the developmental origins and trajectories of neuropsychiatric disorders, with particular focus on autism spectrum disorder and ADHD. These neurodevelopmental conditions emerge early in childhood through complex interactions between genetic and environmental factors. We explore psychiatric somatic comorbidity, particularly the unexpected overlap between ADHD and lower urinary tract symptoms (LUTS), which reveals shared neuroendocrine mechanisms involving the HPA axis and autonomic nervous system. Additionally, we investigate pharmacogenetic interactions in ADHD, examining how genetic profiles influence stimulant treatment outcomes and the risk of developing psychotic and bipolar disorders in treated youth.

    We also study severe postpartum psychiatric disorders, particularly postpartum psychosis, which represents a critical window for understanding psychiatric vulnerability. Through rare variant analyses and large scale genomic cohorts, we characterize the genetic architecture of these conditions and identify pregnancy specific triggers.

Articles

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Grants

  • The Role of Stimulant Medication for Psychotic and Bipolar Disorders in Youth with ADHD
    Swedish Research Council
    1 January 2026 - 31 December 2029
  • Swedish Research Council
    1 January 2026 - 31 December 2029
    This five-year project investigates how stimulant treatment influences the risk of psychotic and bipolar disorders in youth with ADHD. While stimulants provide significant therapeutic benefits, they may precipitate severe psychiatric complications in vulnerable individuals. To identify risk and protective factors, we will examine: (1) stimulant type, dose, and duration effects
    (2) shared genetic and environmental factors
    (3) individual vulnerabilities and stressors
    and (4) ADHD symptom-specific contributions.We will analyze two complementary datasets: Swedish national registers (1,269,516 individuals, 86,705 with ADHD) and detailed clinical data from Uppsala´s Child and Adolescent Psychiatric unit (6,000 individuals). Using advanced statistical methods, including time-to-event analyses, family-based quasi-experimental designs, and statistical genetic models, we will distinguish medication effects from familial influences.Given the 119% increase in ADHD diagnoses in Sweden over the past decade, this research addresses an urgent public health concern. Findings will improve risk assessment, inform safer prescribing practices, and guide personalized ADHD treatment to prevent severe psychiatric outcomes, including suicide, in high-risk youth.
  • Mechanism of Association Between Childhood Psychiatric Disorder and Lower Urinary Tract Symptoms
    Swedish Research Council
    1 January 2026 - 31 December 2028
  • Swedish Research Council
    1 January 2026 - 31 December 2028
    This project explores the bidirectional relationship between psychiatric disorders (ADHD, OCD, anxiety) and urinary problems in children. We aim to: (1) identify genetic factors in neuroendocrine pathways contributing to this co-occurrence
    (2) determine how these genetic factors influence gene expression in relevant tissues
    and (3) track how these conditions develop over time and are affected by environmental factors.Spanning five years, this project brings together experts in urology, psychiatry, and genetics from Karolinska Institutet and Mount Sinai. We will analyze data from Swedish registers, international cohorts (All of Us, ABCD Study), and Swedish Twin Registry. The first two years will focus on genetic analysis, the third year on gene expression, and the final two years on developmental trajectories and data integration. The project employs pathway-specific genetic risk scores, sex-stratified analyses, and longitudinal modeling.This research reframes urinary symptoms as potential markers of broader neuroendocrine dysfunction affecting both body and brain. By understanding how stress-response systems connect these conditions, we can identify children at highest risk and determine optimal timing for intervention. This approach targeting shared biological mechanisms will improve outcomes for these vulnerable children.
  • National Institute of Mental Health
    1 July 2025 - 30 April 2026
  • National Institute of Mental Health
    15 January 2023 - 31 December 2024
  • Swedish Research Council
    1 January 2022 - 31 December 2024

Employments

  • Research Specialist, Department of Molecular Medicine and Surgery, Karolinska Institutet, 2022-
  • Research Specialist, Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, 2023-2026

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