# 23 - Obsessive compulsive disorder

# Obsessive-compulsive disorder

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patient may drop fainting with low BP and bradycardia. There is a high prevalence of the condition 
among first-degree relatives of affected people (Marks 1988) 
About 5% of adults have a fear of the dental procedures. It can 
become so severe that all dental treatment is avoided, and 
dangerous caries develops (Gale and Ayer 1969). 
DSM-IV specifies that in adults, but not children, an appreciation 
of the unreasonable or excessive nature of the fear to diagnose 
specific phobias. The duration criteria of 6 months is specified 
only for children, not adults; as many irrational fears in children 
may be transient and developmental (this is changed in DSM-V, 
see the box above). 
Obsessive-compulsive disorder 
OCD is characterised by obsessional thinking, compulsive 
behaviour and often associated with marked anxiety and 
depression. 
Diagnosis according to ICD10 obsessions (thoughts, images, or 
ideas) and compulsions share the following features, all of 
which must be present: 
(1) Acknowledged as originating in the mind of the 
patient 
(2) Repetitive and unpleasant; at least one recognised as 
excessive or unreasonable 
(3) At least one must be unsuccessfully resisted (although resistance may be minimal in some 
cases) 
(4) Carrying out the obsessive thought or compulsive act is not intrinsically pleasurable 
 
Obsessions can occur in several forms such as thoughts, ruminations, doubts, impulses and phobias. 
Obsessional slowness can occur as a result of Obsessional doubts or compulsive rituals. According to 
ICD-10, either obsessions or compulsions (or both) present on most days for a period of at least two 
successive weeks. 
Common symptoms: Checking (63%), washing (50%), fear of contamination (45%), doubting (42%), 
bodily fears (36%), counting (36%), insistence on symmetry (31%), aggressive thoughts (28%) (Data 
from OxfordHandbook of Psychiatry) 
Compulsive hoarding may be a neurobiologically distinct form of obsessive-compulsive disorder. 
Hoarding is notoriously difficult to treat by either psychological or pharmacological means. Symmetry 
obsessions tend to be chronic and treatment resistant. 
DSM-5 AND OCD 
A new exclusive chapter has been 
created to describe obsessive-compulsive 
and related disorders (not clubbed with 
anxiety disorders anymore). 
2 new diagnoses are included in this 
chapter. 
 1. Hoarding Disorder with core 
symptom being the inability (or 
persistent difficulty) to discard or give 
up possessions, regardless of their actual 
value. 
2. Excoriation Disorder 
(dermatillomania) with core symptom of 
compulsively  picking  one’s  own  skin  for  
no apparent reason.