Paul Arnold

AIHS Translational Health Chair

Child and Youth Mental Health


Departments of Psychiatry & Medical Genetics

Adjunct Scientist

Hospital for Sick Children, University of Toronto

Full Member

Hotchkiss Brain Institute

M.D. (Doctor of Medicine)

Ph.D. (Doctor of Philosophy)


Contact information


Office : TRW4D60

Research and teaching

Research areas

  • Mental Health
  • Obsessive-Compulsive Disorder
  • anxiety disorders
  • child adolescent mental health
  • genetics
  • neurobiology

Research activities

I am the Director of the Mathison Centre for Mental Health Research & Education, and was previously at the Hospital for Sick Children in Toronto. My research focuses on the genetics and neurobiology of childhood obessesive-compulsive disorder (OCD) and related neuropsychiatric disorders. I am a Child and Adolescent Psychiatrist with particular expertise in pediatric OCD.


Arnold PD, Hanna GL, Rosenberg DR. Imaging the amygdala: Changing the face of gene discovery in child psychiatry. Journal of the American Academy of Child and Adolescent Psychiatry 49(1): 7-10. (2010).

Ornstein TJ, Arnold PD, Manassis K, Mendlowitz S, Schachar RJ. Neuropsychological performance in childhood OCD: A preliminary study. Depression and Anxiety 27(4):372-80 (2010). Epub Dec 3, 2009.

Nicolini H, Arnold PD, Nestadt G, Lanzagorta N, Kennedy JL: Overview of genetics and obsessive-compulsive disorder. Psychiatry Research 170:7-14 (2009).

Arnold PD, MacMaster FP, Richter MA, Hanna GL, Sicard T, Burroughs E, Mirza Y, Easter PC, Rose M, Kennedy JL, Rosenberg DR: Glutamate receptor gene (GRIN2B) associated with reduced anterior cingulate glutamatergic concentration in pediatric obsessive-compulsive disorder. Psychiatry Research: Neuroimaging 172(2): 136-139 (2009) “Recommended” rating by Faculty of Medicine 1000”.

Arnold PD, MacMaster FP, Hanna GL, Richter MA, Sicard T, Burroughs E, Mirza Y,Easter PC, Rose M, Kennedy JL, Rosenberg DR: Glutamate system genes associated with ventral prefrontal and thalamic volume in pediatric obsessive-compulsive disorder. Brain Imaging and Behavior 3: 64-76. (2009).

Arnold PD, Sicard T, Burroughs E, Richter MA, Kennedy JL: Glutamate transporter gene (SLC1A1) associated with obsessive-compulsive disorder. Archives of General Psychiatry. 63(7): 769-76. (2006).

Hu X-Z, Lipsky RH, Zhu G, Akhtar LA, Taubman J, Greenberg BD, Xu K, Arnold PD, Richter MA, Kennedy JL, Murphy D, Goldman D: Serotonin transporter gain-of-function polymorphisms are linked to obsessive-compulsive disorder. American Journal of Human Genetics. Am J Hum Genet. 78:815-826 (2006). Epub March 28, 2006.

Arnold PD, Ickowicz I, Chen S, Schachar RJ: Attention deficit disorder with and without obsessive compulsive disorder: clinical characteristics, cognitive assessment and risk factors. Canadian Journal of Psychiatry. 50(1): 59-66 (2005).

Arnold PD, Rosenberg DR, Mundo E, Tharmalingam S, Kennedy JL, Richter MA. Association of a glutamate (NMDA) subunit receptor gene (GRIN2B) with obsessive-compulsive disorder: a preliminary study. Psychopharmacology (Berl). 174(4): 530-538 (2004). Epub 2004 Apr 09.

Arnold PD, Siegel-Bartelt J, Cytrynbaum C, Teshima I, Schachar R: Velo-cardio-facial syndrome: Implications of microdeletion 22q11 for schizophrenia & mood disorders. American Journal of Medical Genetics (Neuropsychiatric Genetics) 105:354-362. (2001).