• Causal modelling of variation in clinical practice and long-term outcomes of ADHD using Norwegian registry data: The ADHD controversy project 

      Mykletun, Arnstein; Widding-Havneraas, Tarjei; Chaulagain, Ashmita; Lyhmann, Ingvild; Bjelland, Ingvar; Halmøy, Anne; Elwert, Felix; Butterworth, Peter; Markussen, Simen; Zachrisson, Henrik Daae; Rypdal, Knut (Journal article; Peer reviewed, 2021)
      Introduction Attention-deficit/hyperactivity disorder (ADHD) is among the most common mental disorders in children and adolescents, and it is a strong risk factor for several adverse psychosocial outcomes over the lifespan. ...
    • Geographical variation in ADHD: do diagnoses refect symptom levels? 

      Widding-Havneraas, Tarjei; Markussen, Simen; Elwert, Felix; Lyhmann, Ingvild; Bjelland, Ingvar; Halmøy, Anne; Chaulagain, Ashmita; Ystrøm, Eivind; Mykletun, Arnstein; Zachrisson, Henrik Daae (Journal article; Peer reviewed, 2022)
      Rates of ADHD diagnosis vary across regions in many countries. However, no prior study has investigated how much within-country geographic variation in ADHD diagnoses is explained by variation in ADHD symptom levels. We ...
    • Preference-based instrumental variables in health research rely on important and underreported assumptions: a systematic review 

      Widding-Havneraas, Tarjei; Chaulagain, Ashmita; Lyhmann, Ingvild; Zachrisson, Henrik Daae; Elwert, Felix; Markussen, Simen; McDaid, David; Mykletun, Arnstein (Journal article; Peer reviewed, 2021)
      Objective: Preference-based instrumental variables (PP IV) designs can identify causal effects when patients receive treatment due to variation in providers’ treatment preference. We offer a systematic review and methodological ...