Types of Psychological Disorders
High-Yield Summary
- Schizophrenia: ≥6 months continuous disturbance, ≥1 month active symptoms. Positive symptoms = added (delusions, hallucinations, disorganized thought/behavior, catatonia); negative symptoms = missing (flat/blunted/inappropriate affect, avolition).
- Delusion subtypes: reference (things directed at you), persecution (plotted against), grandeur (remarkable — common in bipolar), thought broadcasting (thoughts sent out), thought insertion (thoughts placed in). Catatonia includes echolalia (repeating words) and echopraxia (imitating actions).
- Depressive: MDD = ≥5/9 symptoms over 2 weeks incl. depressed mood/anhedonia; persistent depressive disorder = dysthymia ≥2 years; seasonal affective disorder = seasonal-onset presentation, not a standalone DSM diagnosis.
- Bipolar I = manic episode (± MDE); bipolar II = hypomania + ≥1 MDE (never a full manic episode). Manic episode = ≥1 week elevated mood + ≥3 symptoms (distractibility, ↓sleep need, grandiosity, racing thoughts, ↑goal-directed activity, pressured speech, risk-taking); may include psychosis. Hypomania doesn't impair functioning/no psychosis. Cyclothymic disorder = hypomania + dysthymia (neither severe enough for full diagnosis).
- Anxiety: GAD = disproportionate persistent worry about many things; specific phobia = one object/situation; social anxiety disorder = social/performance situations; agoraphobia = fear of being unable to escape; panic disorder = repeated panic attacks, often with agoraphobia.
- OCD (ego-dystonic, obsessions→tension→compulsions relieve it) ≠ body dysmorphic disorder (appearance preoccupation) ≠ OCPD (ego-syntonic, lifelong perfectionist personality — a Cluster C personality disorder).
- PTSD (>1 month: intrusion, avoidance, negative cognitive, arousal symptom clusters) vs. acute stress disorder (same symptoms, 3 days–1 month) — duration is the key differentiator.
- Dissociative disorders (escape from identity via stress): amnesia (can't recall past, non-neurological), fugue (sudden wandering + confused identity), DID (≥2 personalities, often childhood abuse), depersonalization (detached from own mind/body)/derealization (detached from surroundings) — no delusions/hallucinations, unlike psychotic disorders.
- Somatic: somatic symptom disorder (bodily symptom + disproportionate concern), illness anxiety disorder (preoccupied with having/developing illness), conversion disorder (unexplained motor/sensory symptoms after stress, la belle indifférence = unconcerned about own symptom).
- Personality disorders: ego-syntonic (behavior feels correct to the person) vs. most other disorders which are ego-dystonic (feels intrusive/bothersome). Cluster A = odd/eccentric (paranoid, schizotypal, schizoid); B = dramatic/erratic (antisocial, borderline, histrionic, narcissistic); C = anxious/fearful (avoidant, dependent, OCPD).
Key Terms
- Positive symptoms
- Schizophrenia symptoms added to normal experience: delusions, hallucinations, disorganized thought/behavior, catatonia.
- Negative symptoms
- Schizophrenia symptoms that are an absence of normal behavior: disturbance of affect, avolition.
- Prodromal phase
- Poor-adjustment period preceding schizophrenia's active phase — withdrawal, deterioration, peculiar behavior.
- Splitting
- Borderline personality disorder defense mechanism: viewing others as all good or all evil.
- La belle indifférence
- Conversion disorder feature: the person seems unconcerned by their own symptom.
- Ego-syntonic
- The individual sees their own (maladaptive) behavior as correct/normal — the hallmark of personality disorders.
Personality Disorder Clusters
| Cluster | Descriptor and disorders |
|---|---|
| A | Odd/eccentric — Paranoid, Schizotypal, Schizoid |
| B | Dramatic/emotional/erratic — Antisocial, Borderline, Histrionic, Narcissistic |
| C | Anxious/fearful — Avoidant, Dependent, OCPD |
Anxiety Disorder Triggers
| Disorder | Trigger |
|---|---|
| GAD | Disproportionate, persistent worry about many things |
| Specific phobia | One specific object/situation |
| Social anxiety disorder | Social or performance situations |
| Agoraphobia | Places/situations that would be hard to escape |
| Panic disorder | Repeated, unexpected panic attacks |
Common MCAT Trap
- Sort a schizophrenia symptom into positive (added) or negative (missing) before naming anything else.
- Bipolar I vs. II hinges on episode type, not severity label: I requires a full manic episode; II requires hypomania + MDE and never a manic episode.
- OCD (ego-dystonic, acquired) ≠ OCPD (ego-syntonic, lifelong personality trait) — sound alike, different categories entirely.
- PTSD vs. acute stress disorder is a duration question: >1 month vs. 3 days–1 month, same symptom clusters.
- DID and dissociative disorders generally do NOT involve delusions or hallucinations — that would point to a psychotic disorder instead.
Quick Recall
A patient reports hearing voices commenting on their actions and shows flat affect. Which symptoms are positive vs. negative?
A patient has a week of grandiosity, racing thoughts, and psychotic features during an elevated mood episode, plus past depressive episodes. Diagnosis?
A patient is distressed by intrusive thoughts and performs rituals to relieve the resulting tension. OCD or OCPD?
Symptoms match PTSD's four clusters but have lasted 10 days. Diagnosis?
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