obsessive compulsive disorder

how common are intrusive thoughts?

90% of population

what differentiates intrusive thoughts in the general population from those with OCD?

• most people are able to dismiss or to tolerate their intrusive thoughts pretty easily

• people with OCD are not

describe the diagnostic criteria of compulsions and obsessions in the DSM

obsessions

• recurrent and persistent thoughts, urges, images that are experienced as intrusive/unwanted, and in most individuals cause anxiety/distress

• the individual attempts to ignore or suppress such thoughts, urges, images or to neutralize them with some other thought or action

compulsions

• repetitive behaviors or mental acts that the individual feels driven to perform in response to an obsession or according to rules that must be applied rigorously

• the behaviors or mental acts are aimed at preventing or reducing anxiety or distress, or preventing some event or situation

  • these behaviors or mental acts are not connected in a realistic way with what they are designed to neutralize or prevent, or are clearly excessive

in pediatric cases, are compulsions and obsessions equally present?

in cases of onset before puberty

• patients often present with compulsions

• absence of obsessions

what is the developmental trajectory of OCD?

• ~80% of cases emerge before 18 years

• ~67% of children with OCD continue to show symptoms up to 14 years later

describe comorbidity trends with OCD (describe any gender differences)

• tic disorders

  • tourette syndrome

  • depression

  • odd

  • adhd

• anxiety (most common) ~75%

• rates of OCD are comparable across boys and girls

  • boys tend to have an earlier onset

  • most boys onset before puberty

  • most girls onset after puberty

describe how the worry circuit in the brain relates to OCD

• basal ganglia

  • caudate, striatum

  • set of nuclei in the cerebrum that contain inhibitory neurons

• related to inhibiting and controlling responses, which can select or amplify certain inputs

• plays a key role in habit formation

worry circuit

• basal ganglia communicate with other parts of brain (frontal cortex, cingulate gyrus, thalamus)

  • circuit is hyperactive in people with OCD

what effects do SSRIs have on OCD?

• fluoxetine is associated with significant declines in activity in the caudate and the thalamus

  • both part of the worry circuit

how do effects of SSRIs on OCD differ from depression?

• medication and therapy seem to have similar neural mechanisms of action for OCD

• in depression, meds and therapy influenced different parts of the brain