Obsessive-Compulsive Disorder

Question 1

What are obsessions?

Answer 1

Intrusive and recurring thoughts, images, or impulses that come unbidden to the mind, are uncontrollable, and usually appear irrational to the person experiencing them

Question 2

Which forms do obessions often take? (5)

Answer 2

• wishes
• impulses
• images
• ideas
• doubts

Question 3

What are compulsions?

Answer 3

Repetitive, clearly excessive behaviors or mental acts that the person feels driven to perform in order to prevent or reduce anxiety

Question 4

What is the difference between intrusive thoughts and ritualistic behaviors in the general population and in the OCD population?

Answer 4

In OCD they are psychopathological:

• time consuming
• cause marked distress
• interfere with everyday functioning

Question 5

What is the lifetime prevalence and mean onset of age of OCD?

Answer 5

Lifetime prevalence: 2-3%

Mean onset of age: 20 years

Question 6

What are common comorbidities of OCD? (5)

Answer 6

• motor tics (including TS)
• trichotillomania (=compulsive hair pulling)
• body dismorphic disorder
• mood disorders
• anxiety disorders

Question 7

What is the etiology of OCD?

Answer 7

• genetic component (precise is unknown)
• neurotransmitters: serotonin (and others e.g. DA)
• brain imaging abnormalities: OFC, ACC, striatum)
• cortico-striatal model

Question 8

What is the cortical-striatal model of OCD?

Answer 8

Abnormal striatal funtioning

• > inefficient gaiting at the level of the thalamus
• > hyperactivity within the OFC and ACC

Question 9

Name 3 treatment possibilities of OCD`

Answer 9

1) behavior therapy
2) pharmacotherapy (SRI’s)
3) deep brain stimulation

Question 10

What are the 2 forms of modern neurosurgery?

Answer 10

• ablatve procedure

- neuromodulation

Question 11

What is the procedure and mechanism of action in DBS?

Answer 11

• placement of one (sometimes two) small electrodes deep into the brain’s subcortical structures
• DBS appears to disrupt abnormal patterns of neuronal activity associated with structures implicated in disorder-specific pathophysiology
• effects of DBS are locally and ar distance

Question 12

What are the advantages (2) of DBS?

Answer 12

• non-ablative procedure

- reversible and adjustable

Question 13

What kind of adverse effects are there of DBS?

Answer 13

• surgical procedure (bleedings, infections,

Question 14

What is the role of neuropsychologists in DBS? (3)

Answer 14

• patient selection
• evaluation of outcome
• managment of post-operative effects

Question 15

What is likely to represent the neurobiological basis of inhibitory failures in OCD?

Answer 15

Abnormalities in neural circuitry connecting cortical to subcortical structures (particularly the lateral-orbitofrontal loop)

Question 16

What has been found regarding the hypothesis ‘impaired implicit learning in patients with OCD’?

Answer 16

Inconsistent findings, evidece suggests that:
because of dysfunctional fronto-striatal systems, patients may use medial temporal networks associated with explicit learning to compensate for striatal dysfunction
-> parallel processing of explicit information may have “preoccupied” frontal-temporal systems, thereby preventing subjects with OCD from employing these structures for implicit learning

Question 17

What is the rationale of the hypothesis ‘impaired implicit learning in patients with OCD’?

Answer 17

Compulsions occur in an attempt to be reassured that the task was competed when implicit processubf is deficient