Psychopathology Obsessivecompulsive disorder

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Psychopathology Obsessive-compulsive disorder
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Prefrontal Cortex
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Cortico-Striatal-Thalamo-cortical loops

• Orbitofrontal cortex
• Personality, emotion, response inhibition, and
  social behavior
• Dorsolateral cortex
• Executive functioning, planning, attention,
  working memory
• Anterior cingulate cortex
• Initiative, motivation

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OCD

• Obsessions persistent thoughts
• Compulsions persistent behaviors
• Individual is aware that the behavior or
  obsession is unreasonable or excessive

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OCD

• ONSET
• males, childhood, often associated with tic
  disorders
• Females, puberty and early adulthood
• 3.3 million adults in the United States (2-3 )
• Cross-cultural studies find symptoms are similar
  in various racial and ethnic groups

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Associated Disorders

• Associated Disorders
• Trichotillomania
• Onychophagia
• Co-morbidity
• Depression
• Tourettes
• body dysmorphic disorder
• Eating disorders

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Neuropathology

• Imaging studies
• Structural increases or decreases in size of the
  orbitofrontal cortex, striatum, or thalamus
• Increased activity in caudate, orbitofrontal
  cortex, cingulate cortex
• Dysfunction of cortical/basal ganglia loop
• Huntingtons, Tourettes, maybe Parkinsons,
  Sydenhams chorea also exhibit OCD
• Remember craving and compulsive drug-taking?

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Structural alterations
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Reduced left orbitofrontal cortex in OCD patients
correlates with severity of symptoms
Kang, et al., 2004, J Neuropsychiatry Clin
Neurosci
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Alterations in the anterior cingulate and globus
pallidus
Drug-naïve patients
Szeszko et al., Am J Psychiatry 2004
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Reduced caudate volume
Denys, et al. 2004 Biol Psychaitry
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Altered function of the cortico-striatal-thalamo-c
ortical loop
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At rest

• Increased activity of the orbitofrontal cortex
• Increased activity of the cingulate cortex
• Increased activity in the caudate nucleus
• Increased activity in the thalamus

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Overactivity of prefrontal-basal ganglia loops
Baxter et al., 1998
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Increased activity in the thalamus
Saxena et al., Biol Psychiatry, 2001
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Hyperactivity is exacerbated during symptom
provocation
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Breiter et al (1996)

• fMRI
• Contaminated items vs neutral items
• Handling of contaminated items exacerbated
  activity in the prefrontal cortical areas
  (anterior cingulate, orbitofrontal), the basal
  ganglia, and the amygdala

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Activation in the orbitofrontal cortex and
amygdala during symptom provocation
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Injury-induced OCD
12-year-old female, struck by car Max et al. 1995
Chako et al., 2004
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Overactivity of cortico-basal ganglia

• Baseline
• During provocation of symptoms
• OCD can be caused by damage to the basal ganglia
• OCD occurs in other prefrontal-basal ganglia
  disorders

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Altered Direct/Indirect Pathway Balance

• Overactivity of the DIRECT LOOP

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Dysfunction of habit formation?
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Treatments

• SSRIs
• Adjunctive antipsychotics (dopamine antagonists)
• Behavior therapy
• Psychosurgery
• Effective treatment, pharmacologic or behavioral
  therapy, normalizes activity

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Treatments

• SSRIs
• Adjunctive antipsychotics (dopamine antagonists)
• Behavior therapy
• Psychosurgery

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Normalization of striatal activity with SSRI
treatment

Paroxetine

Saxena et al., 2002
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Normalization of orbitofrontal cortex activation
Saxena et al., 1999
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Treatments

• SSRIs
• Adjunctive antipsychotics (dopamine antagonists)
• Behavior therapy
• Psychosurgery

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Treatments

• SSRIs
• Adjunctive antipsychotics (dopamine antagonists)
• Behavior therapy
• Psychosurgery

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PET scans of OCD patients
OCD, pre-behavior therapy
OCD, pre-drug treatment
OCD, post-behavior therapy
OCD, post-drug treatment
Behavior- or drug therapy produce similar
reductions in the activity of the basal ganglia
From Baxter, et al., 1992, Arch Gen Psychiat, 49
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Either drug treatment or behavioral treatment
normalizes brain activity

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Treatments

• SSRIs
• Adjunctive antipsychotics (dopamine antagonists)
• Behavior therapy
• Psychosurgery

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Psychosurgeries
Probes are inserted through the skull
into cingulum.
Cingulotomy
Destroy connections between the frontal lobe and
basal ganglia/limbic structures
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Psychosurgery Success

• 27 definite improvement, 27 probably
  improvement, 46 no improvement (Baer et al,
  1995)
• 32 definite improvement, 14 partial
  improvement, 54 no improvement (Dougherty et al,
  2002)

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Patient-conducted psychosurgery?
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Psychosurgeries
Deep Brain Stimulation
1. The surgeon inserts wires through the skull
and into capsule. 2. Wires are permanent and
attached to battery pack implanted in chest. 3.
Battery produces adjustable freq. that has same
effect as the other Surgeries. this has been used
on PD patients.
http//www.erworld.com/sjh_images/OCD.gif
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Summary

• OCD is related to dysfunction of prefrontal-basal
  ganglia loops that lead to repetitive thoughts
  and actions
• Effective treatments normalize this activity
• Treatments include SSRIs, behavioral therapies
  and psychosurgery