Psychological Disorders

Psychological Disorders

Part 1 of 4 — Classifying Disorders: DSM Logic, Anxiety, OCD & Trauma

What Makes Something a Disorder?

No single feature suffices. The working standard combines:

• Dysfunction in psychological, biological, or developmental processes
• Distress to the person and/or impairment in social, occupational, or daily functioning
• NOT merely: statistical rarity, social deviance, or conflict with society — unusual beliefs, nonconformity, or protest alone never qualify

The DSM-5 is the classification standard: categorical (diagnosis met or not, via symptom-count and duration criteria), deliberately atheoretical about causes. The dominant explanatory frame is biopsychosocial — and the diathesis-stress model (a predisposition expressed only under sufficient stress) is its workhorse. Contrast with a purely biomedical model, which the MCAT usually presents as too narrow.

Anxiety Disorders (fear/worry disproportionate and impairing)

Panic attacks mimic cardiac emergencies — passages love the ER vignette with normal workup.

Obsessive-Compulsive & Related

• Obsessions: intrusive, unwanted, anxiety-producing thoughts/urges/images the person tries to suppress — recognized as products of their own mind
• Compulsions: repetitive behaviors or mental acts performed to neutralize obsession-driven anxiety or by rigid rules
• The maintaining engine is negative reinforcement (learning lesson tie-in): the ritual briefly removes anxiety, strengthening the ritual — which is why exposure WITH response prevention is the behavioral treatment
• Related: body dysmorphic disorder, hoarding disorder

Trauma & Stressor-Related

PTSD requires a qualifying traumatic exposure plus four symptom clusters:

1. Intrusion (flashbacks, nightmares, intrusive memories)
2. Avoidance of reminders
3. Negative alterations in cognition/mood (blame, detachment, anhedonia)
4. Alterations in arousal/reactivity (hypervigilance, exaggerated startle, sleep disturbance)

Duration boundary: symptoms > 1 month = PTSD; a similar picture lasting up to 1 month = acute stress disorder. Adjustment disorder = disproportionate distress after a NON-catastrophic stressor.

• Acute stress disorder's window formally runs from 3 days to 1 month after the trauma.

Worked Example — An Emergency-Department Vignette, Fully Read

Vignette. A 23-year-old graduate student has three episodes in six weeks of abrupt palpitations, chest tightness, shortness of breath, dizziness, and an overwhelming feeling that she is dying, each peaking within about ten minutes and resolving within the hour. Cardiac and thyroid workups are normal. Since the second episode she has stopped attending lectures held in the large auditorium, sits near exits, and repeatedly checks her pulse. She reports the episodes "come out of nowhere," including one that woke her from sleep. She also mentions long-standing but manageable nervousness before presentations.

Step 1 — name the events, then the disorder. The episodes are panic attacks: abrupt surge, rapid peak, somatic storm plus catastrophic cognition. The DIAGNOSIS of panic disorder is supported by what happens BETWEEN attacks — a month-plus of anticipatory worry and maladaptive behavior change (avoiding the auditorium, exit-sitting, pulse-checking). Attacks alone, without the inter-attack syndrome, would not suffice.

Step 2 — use the discriminators the vignette planted. "Out of nowhere," including from sleep = UNEXPECTED attacks, pointing away from specific phobia or social anxiety, where attacks are cued by an identifiable trigger. Her presentation nervousness is subclinical and situational — a distractor inviting an unjustified social anxiety diagnosis. The normal medical workup removes the great mimics (cardiac, thyroid) that any competent item will mention.

Step 3 — track the developing complication. Avoidance of the auditorium and preference for escape routes is early agoraphobic avoidance — fear of situations where escape would be difficult if an attack struck. If it generalizes (transit, crowds, leaving home), agoraphobia becomes a second diagnosis.

Step 4 — connect mechanism to treatment logic. The maintaining cycle is interoceptive: bodily sensations → catastrophic appraisal → sympathetic surge → stronger sensations. Behavioral treatment (interoceptive exposure — deliberately inducing the feared sensations) breaks the association, and the safety behaviors (pulse-checking, exit-sitting) must be withdrawn because they function as negative reinforcers preserving the fear — the same operant engine as OCD rituals.

DSM Logic, Anxiety & Trauma 🎯

Key Takeaways — Part 1

• Disorder = internal dysfunction + distress/impairment; rarity and social deviance never suffice; DSM-5 is categorical and atheoretical; diathesis-stress is the default causal frame
• Anxiety map: GAD = broad, uncontrollable, 6+ months; phobia/social anxiety = cued fear; panic disorder = unexpected attacks PLUS a month of fear-of-the-fear; agoraphobia = fear of unescapable situations
• Panic attacks are events, not a diagnosis — the inter-attack syndrome makes the disorder; normal cardiac workup is the vignette's signal
• OCD: ego-dystonic obsessions + anxiety-neutralizing compulsions run on negative reinforcement (hence exposure with response prevention)
• PTSD's four clusters (intrusion, avoidance, negative cognition/mood, hyperarousal); over 1 month = PTSD, under = acute stress disorder; adjustment disorder = ordinary stressor, disproportionate response

• Low-yield extras: acute stress disorder's formal window starts 3 days after the trauma

Psychological Disorders

Part 2 of 4 — Mood Disorders & Schizophrenia

Major Depressive Disorder (MDD)

Diagnosis requires ≥ 5 symptoms for ≥ 2 weeks, including at least one of the two cardinal symptoms:

• Depressed mood most of the day, nearly every day
• Anhedonia — markedly diminished interest or pleasure

Plus: appetite/weight change, insomnia or hypersomnia, psychomotor agitation/retardation, fatigue, worthlessness or inappropriate guilt, impaired concentration, recurrent thoughts of death. Persistent depressive disorder (dysthymia): milder but chronic — depressed mood more days than not for ≥ 2 years. Seasonal pattern responds to light therapy.

Biological correlates (correlates, not proven single causes):

• Monoamine hypothesis: reduced serotonin/norepinephrine signaling; supported by antidepressant pharmacology, but the weeks-long therapeutic lag despite immediate synaptic effects shows it is incomplete (current work emphasizes downstream neuroplasticity)

• The best-studied neuroplasticity signal is brain-derived neurotrophic factor (BDNF), which chronic antidepressant treatment raises.

• HPA axis hyperactivity (elevated cortisol); reduced hippocampal volume in chronic illness
• Suicide risk assessment is part of any depression vignette: prior attempts, plan and means, hopelessness, substance use, social isolation — asking about suicide does NOT increase risk

Bipolar Disorders (defined by the ELEVATED pole)

Discriminator: decreased need for sleep (rested after 3 hours) vs. insomnia (tired, cannot sleep). First-line mood stabilizer: lithium; antidepressant monotherapy risks switching a bipolar patient into mania.

Schizophrenia (psychosis = break with reality testing)

Two or more of five criteria (delusions, hallucinations, disorganized speech, disorganized/catatonic behavior, negative symptoms) for a 1-month active phase, with continuous disturbance ≥ 6 months and major functional decline; at least one must be delusions, hallucinations, or disorganized speech. The criteria group as:

• Positive symptoms (added to experience): delusions (fixed false beliefs — persecutory, grandiose, referential), hallucinations (perceptions without stimuli — auditory most common), disorganized speech (derailment, word salad)
• Grossly disorganized or catatonic behavior
• Negative symptoms (subtracted): flat/blunted affect, avolition (loss of motivation), alogia (poverty of speech), anhedonia, asociality — these predict functional outcome best and respond worst to classic drugs

Beyond the diagnostic criteria, cognitive symptoms (working memory, attention deficits) are increasingly emphasized.

Timeline: prodrome (withdrawal, odd beliefs) → active phase → residual. Schizophreniform = same picture 1-6 months; brief psychotic disorder < 1 month; schizoaffective = psychosis meeting schizophrenia criteria PLUS major mood episodes, with delusions/hallucinations also present at times WITHOUT mood symptoms.

• Schizoaffective disorder's formal rule: at least 2 weeks of delusions or hallucinations in the absence of a major mood episode.

Dopamine hypothesis: excess mesolimbic dopamine → positive symptoms (supported by D2-blocking antipsychotics and amphetamine-induced psychosis); mesocortical HYPOactivity linked to negative/cognitive symptoms — one transmitter, two pathways, opposite directions. Glutamate (NMDA hypofunction) is the major newer thread. Etiology: strong heritability + prenatal insults + stress — the diathesis-stress showcase.

Worked Example — A Two-Pathway Pharmacology Passage, Fully Read

Passage. A 21-year-old college junior is brought in after a month of conviction that campus cameras broadcast his thoughts, hearing two voices commenting on his actions, and increasingly tangential speech. His roommate reports a year of gradual withdrawal, declining hygiene, and abandoned activities preceding the acute symptoms. On a D2-antagonist antipsychotic, the voices and delusion fade within weeks, but he remains flat, unmotivated, and socially disengaged; he also develops tremor and rigidity. A research aside notes that amphetamine at high doses reproduces paranoid psychosis in healthy users, and that an NMDA antagonist (ketamine) transiently produces BOTH positive-like and negative-like symptoms in volunteers.

Step 1 — inventory and classify the symptoms. Thought broadcasting delusion + commenting voices + tangential speech = positive symptoms (1-month active phase). The preceding year of withdrawal, avolition, and decline = prodrome contributing to the 6-month duration criterion, and its avolition/flat affect are negative symptoms. Both criteria columns are satisfied — the vignette is built to make you assemble the timeline.

Step 2 — read the treatment response as pathway evidence. D2 blockade relieves positive symptoms → consistent with mesolimbic dopamine EXCESS. Persistence of negative symptoms fits mesocortical HYPOfunction — blocking dopamine cannot fix a pathway that is already underactive (and may worsen it). The motor side effects (tremor, rigidity) are the third pathway: nigrostriatal D2 blockade producing parkinsonism — connect to Parkinson's disease pharmacology, where the therapeutic direction is reversed.

Step 3 — use the drug-model evidence. Amphetamine (dopamine releaser) reproducing ONLY paranoid positive symptoms supports dopamine's sufficiency for that cluster; ketamine reproducing both clusters is the standard argument that NMDA/glutamate hypofunction sits upstream, explaining what the dopamine hypothesis alone cannot — the negative/cognitive symptoms.

Step 4 — the discrimination item to expect. "Which feature best distinguishes his negative symptoms from a co-occurring major depressive episode?" Depression carries prominent depressed MOOD and guilt with intact idea generation; primary negative symptoms present as absence — flat affect and avolition without the subjective sadness — and predate the mood-reactive picture. If a full mood episode dominated the course with psychosis also persisting outside it, schizoaffective disorder would enter the differential — course bookkeeping decides.

Mood Disorders & Psychosis 🎯

Key Takeaways — Part 2

• MDD: 5+ symptoms, 2+ weeks, cardinal = depressed mood OR anhedonia; dysthymia = 2+ years chronic; monoamine hypothesis is supported but incomplete (therapeutic lag → neuroplasticity); HPA/cortisol and hippocampal findings
• Bipolar bookkeeping: mania (1 week, impairment/psychosis/hospitalization) = Bipolar I, no depression needed; hypomania (4 days, no marked impairment) + major depression = Bipolar II; 2 years subthreshold = cyclothymia; decreased NEED for sleep is the tell; lithium stabilizes
• Schizophrenia: 2+ of delusions, hallucinations, disorganized speech, disorganized/catatonic behavior, negative symptoms — at least one of the first three; 1-month active phase within ≥6 months; schizophreniform 1-6 months, brief psychotic under 1 month, schizoaffective = mood episodes plus psychosis that also occurs outside them
• Dopamine hypothesis: mesolimbic excess = positive symptoms (D2 blockers, amphetamine psychosis); mesocortical deficit = negative/cognitive; nigrostriatal blockade = parkinsonian side effects; NMDA hypofunction covers what dopamine alone cannot
• Ask about suicide directly — it assesses risk and does not create it

• Low-yield extras: BDNF as the best-studied neuroplasticity signal in depression; schizoaffective disorder's formal 2-week rule for psychosis without a mood episode

Psychological Disorders

Part 3 of 4 — Personality, Dissociative, Somatic & Neurocognitive Disorders

Personality Disorders (enduring, inflexible, pervasive patterns from early adulthood)

Personality disorders are ego-syntonic (experienced as "just how I am") — a key contrast with the ego-dystonic distress of anxiety disorders — and are grouped in three clusters:

OCD vs. OCPD — a guaranteed item: OCD has intrusive obsessions and anxiety-driven rituals the person finds alien (ego-dystonic); OCPD is a lifelong, ego-syntonic perfectionism with NO true obsessions or compulsions — the person endorses the standards, others suffer them.

Dissociative Disorders (disrupted integration of memory, identity, perception)

• Dissociative identity disorder: ≥ 2 distinct personality states with recurrent gaps in recall; strongly associated with severe early trauma; controversial but tested descriptively
• Dissociative amnesia: inability to recall important autobiographical information, usually trauma-linked, beyond ordinary forgetting — may include fugue (sudden travel with identity confusion)
• Depersonalization/derealization disorder: recurrent detachment from self (observing oneself from outside) or surroundings (world feels unreal), with intact reality testing — the person knows the experience is "not real," which separates it from psychosis

Somatic Symptom & Related Disorders (distress expressed through the body)

• Somatic symptom disorder: ≥ 1 distressing physical symptom PLUS excessive thoughts/anxiety/time devoted to it — the symptom may or may not have medical explanation; the DISORDER lies in the disproportionate response
• Illness anxiety disorder: preoccupation with HAVING a serious disease with minimal or no somatic symptoms
• Conversion disorder (functional neurological symptom disorder): neurological deficits (paralysis, blindness, seizures) incompatible with recognized pathology — deficits are NOT consciously produced
• Contrast (not somatic disorders): factitious disorder = intentional symptom production for the sick ROLE; malingering = intentional production for EXTERNAL gain (not a mental disorder)

Neurocognitive Disorders (the biological-psychology bridge)

Delirium vs. dementia: delirium is ACUTE, fluctuating, with impaired attention/arousal and usually a medical precipitant (infection, drugs) — reversible; dementia is chronic, progressive, with attention relatively spared early.

• Depression in the elderly ("pseudodementia") can mimic dementia but shows quick, low-effort "I don't know" responses (people with dementia tend to try hard and confabulate) and improves with mood treatment.

Worked Example — A Differential-Sorting Passage, Fully Read

Passage. Four hospital consults. Patient 1: a 74-year-old admitted for pneumonia becomes agitated and disoriented on night two, mistakes IV tubing for snakes, drifts in and out of lucidity, and cannot sustain attention; family insists she was "sharp as a tack" last week. Patient 2: a 71-year-old with two years of gradually worsening memory, now getting lost driving familiar routes, with fluent but emptying speech; alert and attentive in interview. Patient 3: a 68-year-old with a pill-rolling tremor at rest, cogwheel rigidity, slowed gait with reduced arm swing, and intact cognition. Patient 4: a 29-year-old with sudden left-arm paralysis after witnessing a violent assault; reflexes, imaging, and nerve conduction are normal, and she seems strikingly untroubled by the deficit.

Step 1 — separate acute from chronic (Patients 1 vs 2). Abrupt onset, FLUCTUATING course, impaired attention/arousal, visual misperceptions, and a medical precipitant (infection) = delirium — a reversible emergency, treated by finding the cause. Patient 2's insidious two-year decline with intact attention is a major neurocognitive disorder; anterograde-first memory loss with spatial disorientation makes Alzheimer's the leading etiology (hippocampus first, plaques and tangles, cholinergic deficit). The attention axis — not memory — is the fastest delirium/dementia discriminator.

Step 2 — localize Patient 3. Resting tremor + rigidity + bradykinesia is the Parkinson triad: substantia nigra dopaminergic loss with Lewy bodies. L-DOPA replaces the missing precursor. Cross-link: D2-blocking antipsychotics produce this same picture pharmacologically (Part 2's nigrostriatal pathway), and excess dopamine therapy can produce psychotic symptoms — the two disorders mirror each other across one transmitter.

Step 3 — read Patient 4 without accusation. Neurological deficit incompatible with anatomy plus normal studies after an acute stressor = conversion disorder (functional neurological symptom disorder). The deficit is not consciously feigned: no external incentive is evident (ruling out malingering) and she is not seeking the sick role through fabrication (ruling out factitious disorder). The calm indifference is a classically described but nonspecific feature — do not diagnose on it alone.

Step 4 — the personality-disorder extension. If a passage adds a lifelong pattern — say, a consultant who has always been rigidly perfectionistic, lists-and-rules driven, and proud of it — the ego-syntonic, trait-like quality (OCPD) separates personality pathology from the episodic, ego-dystonic disorders in this ward. Course and the patient's own attitude toward the symptoms are the two sorting axes for the entire passage.

Clusters, Dissociation & Neurocognitive Disorders 🎯

Key Takeaways — Part 3

• Personality disorders are enduring, pervasive, ego-syntonic; Cluster A odd (paranoid/schizoid/schizotypal), B dramatic (antisocial/borderline/histrionic/narcissistic), C anxious (avoidant/dependent/OCPD)
• Sharp pairs: schizoid (indifferent) vs avoidant (wants but fears); schizotypal (odd, reality testing intact) vs schizophrenia; OCD (ego-dystonic obsessions/rituals) vs OCPD (ego-syntonic perfectionism); antisocial requires age 18 plus earlier conduct disorder
• Dissociative: DID (multiple states + recall gaps, trauma-linked), amnesia with possible fugue (reversible autobiographical loss), depersonalization/derealization (detachment WITH intact reality testing)
• Somatic family: somatic symptom (excessive response to symptoms), illness anxiety (disease fear, few symptoms), conversion (anatomy-incompatible deficits, not feigned); factitious = sick role, malingering = external gain and not a disorder
• Neurocognitive: Alzheimer's = plaques/tangles/ACh/hippocampus; Parkinson's = nigra/dopamine/Lewy bodies/L-DOPA; delirium = acute, fluctuating, attention-first, reversible — dementia is none of those

• Low-yield extras: depressive "pseudodementia" in the elderly mimics dementia but gives quick, low-effort "I don't know" answers and lifts with mood treatment

Psychological Disorders — Deep Dive

Part 4 of 4 — MCAT Integration: Etiology Models, Treatment Logic & Reading Clinical Studies

The Etiology Frameworks (match the mechanism in the stem)

Diathesis-stress integrates them; the biopsychosocial answer is usually the credited one when frameworks compete.

Treatment Logic You Can Derive (not memorize)

• Exposure therapies = classical extinction: present the CS (feared object, bodily sensation, memory) without the feared outcome until the fear response extinguishes. Systematic desensitization adds counterconditioning — relaxation paired stepwise up an anxiety hierarchy; flooding starts at the top; exposure + response prevention (OCD) blocks the negatively reinforcing ritual
• Token economies = operant secondary reinforcement in institutional settings; aversion therapy = counterconditioning with an unpleasant US
• Drug-class map (MCAT altitude): SSRIs — first-line for depression AND most anxiety disorders/OCD (weeks-long lag); benzodiazepines — rapid GABA-enhancing anxiolytics, dependence risk, short-term; antipsychotics — D2 blockade (positive symptoms; motor side effects); lithium — bipolar maintenance; cholinesterase inhibitors — Alzheimer's; L-DOPA — Parkinson's
• Psychotherapy + medication generally outperforms either alone for many conditions

Labeling, Stigma & the Rosenhan Problem

• Diagnostic labels enable communication, prediction, and treatment — but carry stigma: labeled individuals face discrimination, and observers reinterpret normal behavior through the label (in Rosenhan's famous pseudopatient study, ordinary note-taking was charted as pathological "writing behavior"). Its methods have been seriously criticized, but the labeling lesson — expectation shapes clinical perception — remains the tested point
• Medicalization: redefining human variation as disorder expands treatment but risks pathologizing normality (connect to the sociology lessons' social-construction thread)
• Respectful framing matters clinically: the person HAS a disorder; the person IS not the disorder

Reading Clinical Studies — the Checklist

1. RCT anatomy: random assignment (equates groups on unmeasured confounds), placebo control (expectancy effects are large in psychiatry), double-blinding (patient AND rater expectations)
2. Regression to the mean: patients enroll at their worst; untreated improvement is guaranteed on average — the placebo arm absorbs this, which is why "improved from baseline" proves nothing
3. Comorbidity (disorders co-occurring at high rates) muddies specificity claims; self-report scales import reporting biases; dropout (attrition) biases completers toward success
4. Statistical vs. clinical significance: a tiny symptom-scale difference can be "significant" in a huge sample yet meaningless at the bedside — check effect sizes and functional outcomes
5. Diagnostic criteria in passages: count symptoms, check DURATION boundaries (2 weeks MDD; 6 months GAD/schizophrenia; 1 month PTSD/panic's inter-attack worry), and confirm impairment — most pseudo-diagnoses in answer choices fail on duration

Worked Example — An Antidepressant-Trial Passage, Fully Read

Passage. 480 adults with moderate MDD are randomized to SSRI, pill placebo, CBT, or waitlist. Raters blind to condition score symptoms at 0, 8, and 24 weeks. At 8 weeks: SSRI improves 11.2 points from baseline, placebo 8.1, CBT 10.8, waitlist 4.9 (drug vs placebo p = 0.03, d = 0.28). At 24 weeks, relapse among responders is 41% for discontinued SSRI, 22% for CBT. Dropout: 31% SSRI (mostly side effects), 12% CBT. An editorial concludes "antidepressants barely beat sugar pills, so depression is not biological."

Step 1 — read the four arms as machinery. Waitlist improvement (4.9) estimates natural course plus regression to the mean — enrollees start near their nadir. Placebo (8.1) adds expectancy and clinical contact. Only the drug-minus-placebo gap (3.1, d = 0.28) is the pharmacological effect. Never grade any arm against baseline; grade arms against each other.

Step 2 — evaluate the effect honestly. The drug effect is statistically significant but small (d = 0.28) — a statistical-vs-clinical significance flag. CBT matches the drug acutely and HALVES relapse after treatment ends, the classic durability advantage of learned skills over discontinued medication. Differential dropout (31% vs 12%) biases completer analyses toward the drug — intention-to-treat analysis is the requested fix.

Step 3 — dismantle the editorial. Its inference commits a category error twice. First, a modest drug-placebo gap does not mean the drug does nothing — placebo arms in depression trials capture real improvement processes (expectancy, contact, regression), inflating the comparator. Second, treatment response NEVER certifies etiology in either direction: aspirin relieving headaches does not prove headaches are aspirin-deficiency diseases, and CBT working does not prove depression is "just thoughts." Etiology claims need etiological designs (Part 4 of the development lesson), not outcome trials.

Step 4 — the anticipated items. "Why include placebo rather than waitlist alone?" — to separate expectancy/contact effects from natural course. "Why blind the raters?" — observer expectations distort self-report-adjacent measures (the Rosenhan lesson operationalized). "Which patients does the trial's conclusion cover?" — moderate MDD completers under trial conditions; generalization beyond that is an external-validity question the data cannot settle.

Etiology, Treatment & Trial Reading 🎯

Key Takeaways — Part 4

• Frameworks map to treatments: behavioral = exposure/extinction and counterconditioning (desensitization, flooding, response prevention, token economies); cognitive = restructuring; biological = the drug-class map (SSRIs, benzodiazepines, D2 antagonists, lithium, cholinesterase inhibitors, L-DOPA); biopsychosocial integrates
• Treatment response never proves etiology — in either direction
• Labels communicate and predict but also stigmatize and steer observer perception (Rosenhan's enduring lesson, methods critiques notwithstanding); medicalization is the social-construction flip side
• Trial reading: compare arms, never baselines (regression to the mean); placebo isolates expectancy; double-blind protects both patient response and rater judgment; watch differential dropout, comorbidity exclusions (external validity), and effect size vs p-value
• Criteria bookkeeping wins items: 2 weeks MDD, 6 months GAD and schizophrenia, 1 month PTSD and panic disorder's worry criterion — most wrong diagnoses in answer choices fail on duration