Psychological Disorders
This domain tests the criteria for abnormality, the major diagnostic categories, and the symptoms that separate them.
Defining abnormality
Criteria include statistical deviance, violation of social norms, personal distress and maladaptive functioning. No single criterion is sufficient. DSM-5-TR and ICD-11 are classification systems. The diathesis–stress model combines vulnerability with stress; the biopsychosocial model integrates biological, psychological and social factors.
Major disorders
- Anxiety disorders: generalised anxiety, panic disorder, phobias, social anxiety.
- Obsessive–compulsive disorder: obsessions (intrusive thoughts) and compulsions (repetitive acts).
- Mood disorders: major depression; bipolar disorder with manic and depressive episodes.
- Schizophrenia: positive symptoms (delusions, hallucinations, disorganised speech) and negative symptoms (flat affect, avolition, alogia).
- Personality disorders: enduring, inflexible patterns (e.g., borderline, antisocial).
Worked example
A student washes her hands for two hours daily to reduce intrusive contamination thoughts. The thoughts are obsessions and the washing is a compulsion, so this is OCD-not a psychotic disorder.
Traps
OCD is classified with anxiety-related disorders, not schizophrenia. Sadness after a loss is not automatically major depression. Positive symptoms add behaviour; negative symptoms subtract it. Diagnosis requires duration, impairment and exclusion of other causes.