Obsessive Compulsive disorder

Question 1

Point prevalence

Answer 1

• 1-3% of adults

- 1-2% children and adolescents

Question 2

Lifetime prevalence of OCD

Answer 2

• 2-3%

- 4th most commonly prevalent psychiatric disorder in epidemiological studies

Question 3

Gender ratio of OCD

Answer 3

• roughly equal in clinical samples
• females dominate in community populations 1.5:1
• males with OCD show earlier onset and trend toward more tics and poorer outcome than females

Question 4

Presentation of OCD

Answer 4

4 factor model

1. aggressive, sexual and religious obsessions and checking compulsions
2. symmetry and ordering obsessions and compulsions
3. contamination obsessions and cleaning compulsions
4. hoarding obsessions and compulsions

Question 5

Neuroimaging

Answer 5

-hypermetabolism of basal ganglia structures (caudate)

Question 6

D2 antagonism

Answer 6

-D2 antagonists such as clozapine can cause secondary OCD-like symptoms in some patients

Question 7

OCD spectrum disorders

Answer 7

1. those associated with somatic preoccupation e.g AN, BDD, hypochondriasis
2. those associated with neurological disorders e.g Tourettes, Sydenham’s chorea and ASD
3. Those associated with impulse control disorders e.g paraphilias, kleptomania, pathological gambling
4. Anankastic personality

Question 8

PANDAS

Answer 8

• Paediatric autoimmune neuropsychiatric disorders associated with strep infection
• autoantibodies bind to basal ganglia
• produces tics, OCD symptoms and anxiety

Question 9

Diagnostic criteria for PANDAS

Answer 9

1. presence of OCD or Tic disorder
2. Onset between 3 years of age and the beginning of puberty
3. abrupt onset of symptoms or a course characterised by dramatic exacerbations of symptoms
4. the onset of symptoms is temporally related to infection with GABHS
5. Abnormal results of neurological examination (hyperactivity, choreiform movements and tics) during exacerbation

Question 10

Testing for PANDAS

Answer 10

• AntiDNAseB

- Antistreptolysin O titres are elevated

Question 11

Mild to moderate OCD treatment

Answer 11

Step 1: self help
Step 2: CBT with ERP
Step 3: SSRIs +/- CBT

Question 12

Severe OCD treatment

Answer 12

Step 1: SSRIs+/- CBT
Responders: continue SSRI for 1-2 years +/- booster CBT
Non-responders: switch to different SSRI or clomipramine

Question 13

SSRIs and OCD

Answer 13

• 60-70% patients experience some degree of improvement after SSRI treatment
• NNT is 6-12

Question 14

Antipsychotic augmentation

Answer 14

• indicated if no response seen after a three month trial of a maximal dose of SSRI
• also helpful in Tics