Worked example 1
A patient with contamination fears believes they will cause serious illness if they do not wash hands repeatedly after touching door handles.
(a) Explain this OCD using Salkovskis's cognitive theory and the operant conditioning account. [5 marks] (b) Evaluate the serotonin explanation of OCD. [5 marks]
Show solution outline
(a) AO1 — Salkovskis (cognitive):
- Inflated responsibility: Patient believes they have power and duty to prevent illness through washing.
- Thought-action fusion: Touching handle linked to catastrophic outcome — intrusive contamination thought treated as threat requiring neutralisation.
- Overestimation of threat: Exaggerated probability and severity of illness from germs.
AO1 — Operant conditioning:
- Hand-washing reduces anxiety temporarily → negative reinforcement.
- Ritual strengthened each repetition despite long-term maintenance of disorder.
(b) AO3 — Serotonin explanation evaluation:
- Strengths: SSRIs/clomipramine reduce OCD symptoms in RCTs — pharmacological evidence for serotonin involvement.
- Strengths: Consistent with comorbidity with depression/anxiety (shared serotonin system).
- Limitations: Drugs take weeks to work; not all patients respond — incomplete account.
- Limitations: Reductionist — does not explain content of obsessions (why contamination not violence in this case) — cognitive theory needed.
- Correlation vs causation: Low serotonin may be effect of chronic anxiety, not cause.
Judgement: Serotonin explanation supported by treatment evidence but insufficient alone — cognitive and learning accounts explain symptom content and maintenance.