Psychology · Ch 4 — Psychological Disorders
Obsessive-Compulsive and Related Disorders
Obsessive-Compulsive and Related Disorders
Obsessive-compulsive and related disorders are marked by an inability to control certain thoughts or actions, to the point where normal daily life is disrupted. You may have seen someone wash their hands every time they touch an object, or wash coins, or walk only on specific floor tiles. These are not just habits — for the person affected, they are uncontrollable patterns that interfere with functioning.
The core of this category is obsessive-compulsive disorder (OCD). It has two distinct but often linked features.
Obsessive behaviour is the inability to stop thinking about a particular idea or topic. The person finds these repeated thoughts unpleasant and shameful, yet cannot push them away.
Compulsive behaviour is the need to perform certain actions over and over again. Many compulsions involve counting, ordering, checking, touching, and washing. The person feels driven to do these acts, often to reduce the anxiety caused by an obsession.
A common mistake is to call any repeated habit a 'compulsion'. In OCD, the behaviour is not voluntary or enjoyable — it is a response to an intrusive thought, and the person often recognises it as unreasonable but cannot stop.
The textbook also lists other disorders in this category, which are less commonly discussed but equally important for the exam:
- Hoarding disorder — the persistent difficulty discarding possessions, regardless of their actual value.
- Trichotillomania — hair-pulling disorder, where a person repeatedly pulls out their own hair. …