Psychiatric Disorders (Foundations)
Mood, psychosis, anxiety, personality, and the defenses of the ego
Mood disorders
Major depressive episode. Five or more of nine symptoms must last at least 2 weeks, and one of them must be depressed mood or anhedonia. SIG E CAPS covers the rest: Sleep change, loss of Interest, Guilt, low Energy, poor Concentration, Appetite change, Psychomotor change (agitation or slowing) and Suicidality. The monoamine hypothesis ties depression to reduced serotonin, norepinephrine and dopamine signaling. Sleep studies show less slow-wave sleep, a shortened REM latency and more REM early in the night; patients also have early-morning awakening. First-line treatment is an SSRI plus psychotherapy, usually cognitive behavioral therapy (CBT).
Mania and bipolar disorder. Mania is summarized by DIG FAST: Distractibility, Impulsivity/Indiscretion, Grandiosity, Flight of ideas, increased goal-directed Activity, decreased need for Sleep and Talkativeness (pressured speech). One manic episode lasting at least 1 week, or any length if it requires hospitalization, defines bipolar I; a depressive episode is not required. Bipolar II is hypomania (at least 4 days, without marked impairment) plus a major depressive episode, with no full manic episode ever. Psychotic features during an elevated mood mean mania, by definition. Mood stabilizers are lithium, valproate and atypical antipsychotics.
An antidepressant given alone to a patient with unrecognized bipolar disorder can precipitate mania, so screen for past manic or hypomanic episodes before prescribing.
Chronic low-grade mood: the 2-year rule. Persistent depressive disorder (dysthymia) is depressed mood on most days for at least 2 years (1 year in children), milder than major depression. Cyclothymia is fluctuating hypomanic and depressive symptoms for at least 2 years that never meet full criteria. Normal grief can mimic depression, but it centers on the loss, comes in waves and usually leaves self-esteem intact. Pervasive worthlessness points instead to depression.
| Disorder | Core requirement | Minimum duration |
|---|---|---|
| Major depressive episode | ≥5 of 9 symptoms, including depressed mood or anhedonia | 2 weeks |
| Bipolar I | ≥1 manic episode; depression optional | 1 week, or any length if hospitalized |
| Bipolar II | Hypomania plus a major depressive episode | Hypomania ≥4 days |
| Persistent depressive disorder | Chronic, milder depressed mood | 2 years (1 year in children) |
| Cyclothymia | Subthreshold hypomanic and depressive symptoms | 2 years |
Anxiety, obsessive-compulsive and trauma-related disorders
Duration and trigger separate them.
- Generalized anxiety disorder: excessive, hard-to-control worry about many things on most days for 6 months or more.
- Panic disorder: recurrent, unexpected panic attacks (sudden palpitations, chest pain, dyspnea, sweating and fear of dying that peak within minutes) followed by at least a month of anticipatory fear of another attack. Long-term treatment is an SSRI plus CBT, and a benzodiazepine aborts the acute attack.
- Obsessive-compulsive disorder (OCD): ego-dystonic obsessions (intrusive, unwanted thoughts) and compulsions (repetitive acts that relieve the anxiety). Treat with an SSRI or clomipramine, plus exposure and response prevention. OCD is associated with Tourette syndrome.
- PTSD vs acute stress disorder: both follow a life-threatening trauma and share intrusions (flashbacks, nightmares), avoidance, negative mood and hyperarousal. Symptoms lasting more than 1 month mean PTSD, and symptoms under 1 month mean acute stress disorder. PTSD is treated with trauma-focused psychotherapy and SSRIs, and prazosin can reduce nightmares.
The 1-month mark after the trauma decides between acute stress disorder and PTSD, because the symptom picture largely overlaps.
Psychotic disorders and the dopamine hypothesis
Schizophrenia. The diagnosis needs 2 or more of the following: delusions, hallucinations, disorganized speech, disorganized or catatonic behavior, and negative symptoms. At least one must be delusions, hallucinations or disorganized speech. Signs must persist for at least 6 months, including at least 1 month of active symptoms. Lifetime prevalence is about 1%. Onset is earlier in men (late teens to 20s) than in women (20s to 30s). Imaging shows enlarged lateral ventricles and reduced cortical volume.
Positive vs negative symptoms. Positive symptoms are added experiences: hallucinations, delusions and disorganized speech or behavior. They respond well to D2 antagonists. Negative symptoms are deficits, remembered as the 5 A's: flat or blunted Affect, Alogia, Avolition, Anhedonia and Asociality. They respond poorly to typical antipsychotics and drive long-term disability.
- Under 1 monthBrief psychotic disorder, often after a stressor, with return to baseline
- 1–6 monthsSchizophreniform disorder
- Over 6 monthsSchizophrenia
- Plus a mood episodeSchizoaffective disorder: needs ≥2 weeks of psychosis without mood symptoms
Related distinctions. If psychosis occurs only during mood episodes, the diagnosis is a mood disorder with psychotic features. Delusional disorder is at least 1 month of fixed delusions without other psychotic symptoms, and daily functioning is largely preserved.
Dopamine hypothesis. Excess mesolimbic dopamine drives positive symptoms, and antipsychotics work mainly by blocking D2 receptors. The blockade is not pathway-selective, so the same action explains both the benefit and the side effects. NMDA-receptor antagonists (PCP, ketamine) reproduce positive and negative symptoms, which points to glutamate hypofunction as well.
| Pathway | Normal role / change in schizophrenia | Effect of D2 blockade |
|---|---|---|
| Mesolimbic | Dopamine excess → positive symptoms | Therapeutic: positive symptoms improve |
| Mesocortical | Dopamine deficit → negative and cognitive symptoms | No benefit; may worsen negative symptoms |
| Nigrostriatal | Motor control | Extrapyramidal symptoms: dystonia, akathisia, parkinsonism, tardive dyskinesia |
| Tuberoinfundibular | Dopamine tonically inhibits prolactin | Hyperprolactinemia: galactorrhea, amenorrhea, gynecomastia |
Personality disorders
General features. Personality disorders are enduring, inflexible and maladaptive patterns that begin by early adulthood, show up across situations and are usually ego-syntonic. They fall into three clusters: A is weird (odd or eccentric), B is wild (dramatic or erratic) and C is worried (anxious or fearful).
| Cluster | Disorder | Hallmark |
|---|---|---|
| A (weird) | Paranoid | Pervasive distrust and suspicion |
| A (weird) | Schizoid | Voluntary social withdrawal; content loner |
| A (weird) | Schizotypal | Eccentric, magical thinking, odd beliefs and perceptions, but no frank psychosis |
| B (wild) | Antisocial | Disregard for others' rights; age ≥18 with conduct disorder before 15; more common in men |
| B (wild) | Borderline | Unstable relationships, impulsivity, self-harm, chronic emptiness, splitting; treat with dialectical behavior therapy |
| B (wild) | Histrionic | Attention-seeking, dramatic |
| B (wild) | Narcissistic | Grandiosity, entitlement, lack of empathy |
| C (worried) | Avoidant | Wants relationships but fears rejection or criticism |
| C (worried) | Dependent | Excessive need to be cared for; clingy |
| C (worried) | Obsessive-compulsive (OCPD) | Rigid, perfectionistic, controlling; ego-syntonic |
Schizoid patients are content alone, schizotypal patients are odd and magical, and avoidant patients want company but fear rejection. OCPD is ego-syntonic (the person sees no problem), whereas OCD is ego-dystonic, with distressing, unwanted true obsessions and compulsions.
Neurodevelopmental disorders
- ADHD: inattention and/or hyperactivity-impulsivity beginning before age 12 and present in 2 or more settings (e.g., home and school). Treat with stimulants such as methylphenidate or amphetamines. Atomoxetine is a nonstimulant option.
- Autism spectrum disorder: persistent deficits in social communication plus restricted, repetitive behaviors or interests, beginning in early childhood.
- Tourette syndrome: multiple motor tics plus at least one vocal tic for more than 1 year, beginning in childhood. It often coexists with OCD and ADHD. Treat with antipsychotics or α2 agonists (clonidine, guanfacine).
- Intellectual disability: deficits in intellectual and adaptive functioning that begin during development.
Ego defense mechanisms
Immature defenses. These largely unconscious maneuvers reduce anxiety but distort reality or relationships:
- Acting out: expressing unacceptable feelings through actions such as tantrums or self-harm.
- Denial: refusing to accept a painful reality.
- Displacement: redirecting an emotion from its real source to a neutral or safer target (angry at the boss, yells at the children).
- Projection: attributing one's own unacceptable feelings to others.
- Regression: reverting to earlier developmental behavior under stress.
- Repression: unconsciously keeping a thought or feeling out of awareness.
- Isolation of affect: separating feelings from events, such as describing a trauma without emotion.
- Reaction formation: behaving in the opposite way to an unacceptable impulse (hostility toward an attending turned into exaggerated courtesy).
- Splitting: seeing people as all good or all bad and swinging between idealizing and devaluing them. It is the hallmark defense of borderline personality disorder.
Mature defenses. Sublimation, Suppression, Altruism and Humor go with healthier adaptation. Sublimation channels an impulse into a socially acceptable act, such as anger into boxing. Suppression is a conscious decision to put off attending to a stressor. Altruism eases distress by helping others, and humor finds what is funny in an anxiety-provoking situation.
The healthy person Slowly Sublimates And Humors. Suppression is conscious, whereas repression is unconscious.