Abnormal psychology and psychopathology (classification, diagnosis, etiology)
This domain tests diagnostic criteria, duration thresholds, and etiological models. The commonest point-losing mistake is choosing a plausible label that fails one duration or exclusion rule.
Classification basics
- Disorder generally requires deviance, distress, dysfunction, and sometimes danger. DSM categorizes with specifiers and severity ratings; the multiaxial system was dropped. Prevalence = current cases in a population; incidence = new cases over time; comorbidity is the rule.
- Etiology is best framed as diathesis-stress: vulnerability plus trigger. Biopsychosocial models integrate genetic, neural, cognitive, and social factors.
Major categories
- Anxiety: generalized anxiety disorder (6 months or more of diffuse worry), panic disorder (recurrent unexpected attacks plus worry or behavior change), specific and social anxiety disorder, agoraphobia. OCD sits in its own chapter: obsessions are intrusive thoughts, compulsions are rituals that reduce distress. PTSD is trauma- and stressor-related with intrusion, avoidance, negative cognition or mood, and arousal beyond 1 month; acute stress disorder spans 3 days to 1 month.
- Mood: major depressive disorder requires 5 or more symptoms for 2 weeks, including depressed mood or anhedonia. Persistent depressive disorder lasts 2 years. Manic episode: 1 week of elevated or irritable mood with increased energy; hypomania: 4 or more days without marked impairment. Bipolar I requires mania; bipolar II requires hypomania plus depression and never mania. Cyclothymia is 2 years of subthreshold swings.
- Schizophrenia spectrum: positive (delusions, hallucinations, disorganized speech), negative (flat affect, avolition, alogia), and cognitive symptoms. Requires 6 months of disturbance with 1 month active. Schizophreniform = 1 to 6 months; brief psychotic disorder = 1 day to 1 month.
- Personality disorders: cluster A odd-eccentric (paranoid, schizoid, schizotypal); B dramatic (antisocial, borderline, histrionic, narcissistic); C anxious (avoidant, dependent, obsessive-compulsive, distinct from OCD).
- Also neurodevelopmental (ADHD, autism spectrum), eating, and neurocognitive disorders.
Worked example
A man has 3 months of delusions and disorganized speech with social decline and no mood episode. Reasoning: duration exceeds 1 month but is under 6, so schizophreniform disorder fits; at 6 months it becomes schizophrenia. Schizoaffective disorder would require mood episodes present most of the time.
Traps
Placing OCD in the anxiety chapter; relabeling hypomania as mania; diagnosing bipolar II when a full manic episode has occurred; swapping prevalence and incidence.