Aetiology and pathogenesis

A genetic predisposition is likely based on twin and genome-wide linkage studies.

• twin studies which group OCD with obsessive personality show concordance rates as high as 87% in monozygotic twins and 47% in dizygotic twins

The following risk factors may be associated with development of OCD:

• developmental factors
  • emotional, physical, and sexual abuse
  • neglect
  • social isolation
  • teasing
  • bullying
• psychological factors
  • over-inflated sense of responsibility
  • magical thinking
  • an intolerance of uncertainty
  • a belief in the controllability of intrusive thoughts
• stressors
  • pregnancy
  • postnatal period

Rarely

• in adults OCD symptoms can be a consequence of certain neurological conditions such as a brain tumour, Sydenham’s chorea, Huntington’s chorea, or frontotemporal dementia or as a complication of brain injury to the frontal lobe or basal skull
• in children it is associated with pediatric autoimmune neuropsychiatric disorder associated with streptococcal infections (PANDAS) in which they develop an abrupt onset of OCD symptoms or tics after infection with group A Streptococcus (1,2)

Reference:

• (1) Veale D, Roberts A. Obsessive-compulsive disorder. BMJ. 2014;348:g2183
• (2) Fenske JN, Schwenk TL. Obsessive compulsive disorder: diagnosis and management. Am Fam Physician. 2009;80(3):239-45