Obsessive compulsive disorder (OCD)

A common, chronic condition, often associated with marked anxiety and depression, characterized by obsessions and compulsions. Obsessions/compulsions must cause distress or interfere with the person's social or individual functioning (usually by wasting time), and should not be the result of another psychiatric disorder. At some point in the disorder, the person recognizes the symptoms to be excessive or unreasonable.

Clinical features
Checking (63%), washing (50%), contamination (45%), doubting (42%), bodily fears (36%), counting (36%), insistence on symmetry (31%), aggressive thoughts (28%).

Mean age: 20 yrs, 70% onset before age 25 yrs, 15% after age 35 yrs. Sex distribution equal. Prevalence: 0.5 2% of general population.

Avoidant, dependent, histrionic traits (-40% of cases), antistatic / obsessive-compulsive traits (15%) prior to disorder. In schizophrenia, 45% of patients may present with symptoms of OCD schizo-obsessive's poorer prognosis). Sydenham chorea (up to 70% of cases) and other basal ganglia disorders (e.g. TS, post-encephalitic parkinsonism).

Co morbidity
Depressive disorder (70%), alcohol- and drug-related disorders, social phobia, specific phobia, panic disorder, eating disorder, tic disorder (up to 40% in juvenile OCD) or TS.

Differential diagnosis
Normal (but recurrent) thoughts, worries, or habits; anankastic PD/OCDPD, schizophrenia; phobias; depressive disorder; hypochondriasis; body dysmorphic disorder; trichotillomania.

•    Psychological Psychotherapy Supportive: valuable (including family members, use of groups); psychoanalytical: no unequivocal evidence of effectiveness (insight-orientated psychotherapy may be useful in some patients). Behavioural therapy Response prevention useful in ritualistic behaviour; thought stopping may help in ruminations; exposure techniques for obsessions. Cognitive therapy so far not proven effective.

•    Pharmacological Antidepressants SSRIs: fluoxetine, fluvoxamine, sertraline, or paroxetine should be considered first-line (no clear superiority of any one agent, high doses usually needed e.g. 60 mg fluoxetine allow at least 12 wks for treatment response, regard as ong-term. Clomipramine (e.g. 300 mg) has specific anti-obsessional action (first-or second-line choice). MAOIs: phenelzine should be considered as third-line if patient resistant to 2 different SSRIs/or clomipramine and SSRI and there are associated panic attacks. Augmentative strategies: buspirone if marked anxiety; antipsychotic (risperidone, haloperidol, pimozide) if psychotic features, tics, or schizotypal traits; lithium if marked depression. Other possibilities include enhancing 5HT function with L-tryptophan or fenfluramine (controversialmay have serious cardiac adverse effects).

•    Physical ECT consider if patient suicidal or severely incapacitated. Psychosurgery may be considered for severe, incapacitating, intractable

cases (i.e. treatment-resistant 2 antidepressants, 3 combination treatments, ECT, and behavioural therapy), where the patient can given informed consent e.g. stereotactic cingulotomy (reported up to 65% success). In theory, disrupts the neuronal loop between the orbitofrontal cortex and the basal ganglia.

Often sudden onset (e.g. after stressful loss event), symptom intensity may fluctuate (contact-related/phasic) or be chronic.

30% significantly improve, 50% show moderate improvement, but 40% have chronic or worsening symptoms. Relapse rates are high for stopping medication.
Prognostic factors

•    Poor prognosis: Giving in to compulsions, longer duration, early onset, bizarre compulsions, symmetry, comorbid depression, delusional beliefs or overvalued ideas, personality disorder (esp. schizotypal PD).
•    Better prognosis: Good premorbid social and occupational adjustment, a precipitating event, episodic symptoms.

Aetiology of OCD
•    Neurochemical Dysregulation of the 5HT system, or 5HT/DA interaction.
•    Immunological Cell-mediated autoimmune factors may be associated (e.g. against basal ganglia peptides).
•    Imaging CT and MRI: bilateral reduction in caudate size. PET/SPECT: hypermetabolism in orbitofrontal gyrus and basal ganglia (caudate nuclei) that normalises following successful treatment (either pharmacological or psychological).
•    Genetic Suggested by family and twin studies (7% of first-degree relatives affected, MZ: 80% DZ: 25%.), no candidate genes as yet identified.
•    Psychological Defective arousal system and/or inability to control unpleasant internal states. Obsessions are conditioned (neutral) stimuli, associated with an anxiety-provoking event. Compulsions are learned (and reinforced) as they are a form of anxiety-reducing avoidance.
•    Psychoanalytical Regression from Oedipal stage to pre-genital anal-erotic stage of development as a defence against aggressive or sexual (unconscious) impulses. Associated defences: isolation, undoing, and reaction formation.

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