12.4 Neurodevelopmental, Eating, Substance-Related, Dissociative, Somatic Symptom, and Neurocognitive Disorders
Key Takeaways
ADHD requires at least six symptoms of inattention and/or hyperactivity-impulsivity (five for people 17 and older) lasting at least six months, with several symptoms present before age 12 and in two or more settings.
Autism spectrum disorder requires persistent deficits in all three areas of social communication plus at least two of four restricted, repetitive patterns of behavior, with symptoms present in the early developmental period.
Substance use disorder is diagnosed from 11 criteria; 2–3 met within 12 months is mild, 4–5 moderate, and 6 or more severe; gambling disorder is the only behavioral addiction in the main DSM-5-TR text.
Anorexia nervosa involves restricted intake leading to significantly low weight, intense fear of weight gain, and disturbed body image; bulimia nervosa and binge-eating disorder both require binges at least once a week for three months, with compensatory behavior only in bulimia.
Delirium is an acute, fluctuating disturbance of attention and awareness, whereas major neurocognitive disorder is a significant decline that interferes with independence; Alzheimer's disease is the most common cause.
Neurodevelopmental, Eating, Substance-Related, Dissociative, Somatic Symptom, and Neurocognitive Disorders
The practice book's Clinical subtopics include diagnostic systems and causes and development of disorders, and the test follows DSM-5-TR terminology and criteria. The anxiety, obsessive-compulsive, trauma, mood, psychotic, and personality disorders are covered in Sections 12.1 to 12.3; this section covers the remaining high-yield classes.
1. Neurodevelopmental Disorders
These disorders begin in the developmental period and produce deficits in personal, social, academic, or occupational functioning.
| Disorder | Core DSM-5-TR Features | High-Yield Facts |
|---|---|---|
| Intellectual developmental disorder (intellectual disability) | Deficits in intellectual functioning and adaptive functioning (conceptual, social, practical) with onset in the developmental period | Severity (mild, moderate, severe, profound) is based on adaptive functioning; IQ is typically about 70 or below allowing for measurement error (Section 6.6) |
| Autism spectrum disorder (ASD) | (A) Persistent deficits in all three of social-emotional reciprocity, nonverbal communication, and developing and maintaining relationships; (B) at least two of four restricted, repetitive patterns (stereotyped movements or speech, insistence on sameness, restricted intense interests, sensory hyper- or hyporeactivity) | Replaced DSM-IV autistic disorder and Asperger's disorder; three severity levels based on support needed; diagnosed about four times more often in males; heritability is high; vaccines do not cause autism |
| Attention-deficit/hyperactivity disorder (ADHD) | At least 6 symptoms of inattention and/or hyperactivity-impulsivity (at least 5 for age 17 and older) for 6 months or more; several symptoms before age 12; present in two or more settings | Presentations: predominantly inattentive, predominantly hyperactive-impulsive, or combined; treated with stimulants (Section 1.3) and behavioral parent training |
| Specific learning disorder | Persistent difficulty in reading, written expression, or mathematics for at least 6 months despite targeted intervention, with skills well below age expectations | Specifiers include impairment in reading (dyslexia, Section 6.5) and mathematics (dyscalculia) |
| Tic disorders | Tourette's disorder: multiple motor tics and at least one vocal tic, present for more than 1 year since first tic onset, beginning before age 18 | Coprolalia (obscene vocalizations) occurs in only a minority; tics often wax and wane and frequently co-occur with ADHD and OCD |
2. Feeding and Eating Disorders
| Disorder | Defining Features | Key Points |
|---|---|---|
| Anorexia nervosa | Restriction of intake leading to significantly low body weight; intense fear of gaining weight or persistent weight-preventing behavior; disturbed experience of body weight or shape | Subtypes: restricting versus binge-eating/purging. Severity for adults is based on BMI (mild: 17 or above; moderate: 16–16.99; severe: 15–15.99; extreme: below 15). Has one of the highest mortality rates of any psychiatric disorder |
| Bulimia nervosa | Recurrent binge eating plus inappropriate compensatory behaviors (vomiting, laxatives, fasting, excessive exercise), both at least once a week for 3 months; self-evaluation unduly influenced by shape and weight | Weight is usually in or above the normal range, which distinguishes it from the binge-purge subtype of anorexia; dental erosion and electrolyte imbalance are medical risks |
| Binge-eating disorder | Recurrent binges at least once a week for 3 months with marked distress and loss of control, without regular compensatory behavior | The most common eating disorder in adults; binges are associated with eating rapidly, eating alone from embarrassment, or feeling disgusted afterward |
| Avoidant/restrictive food intake disorder (ARFID) | Avoidance or restriction of food (because of sensory features, lack of interest, or fear of aversive consequences such as choking) causing weight loss, nutritional deficiency, or dependence on supplements | No body-image disturbance, unlike anorexia |
| Pica and rumination disorder | Persistent eating of nonnutritive substances; repeated regurgitation of food | Pica is diagnosed only when developmentally and culturally inappropriate |
Risk factors for anorexia and bulimia include female sex, adolescence, perfectionism, dieting, cultural thin ideals, and substantial heritability. Cognitive-behavioral therapy is the best-supported treatment for bulimia and binge-eating disorder; family-based treatment (the Maudsley approach) is well supported for adolescents with anorexia.
3. Substance-Related and Addictive Disorders
DSM-5 merged DSM-IV "substance abuse" and "substance dependence" into a single substance use disorder (SUD), diagnosed from 11 criteria grouped as impaired control (using more than intended, unsuccessful efforts to cut down, much time spent, craving), social impairment, risky use, and pharmacological criteria (tolerance and withdrawal).
- Severity: 2–3 criteria within a 12-month period = mild; 4–5 = moderate; 6 or more = severe.
- Tolerance is a reduced effect at the same dose (or the need for more drug); withdrawal is a substance-specific syndrome after reduced use. Tolerance and withdrawal that occur solely during appropriate medical treatment (such as prescribed opioids) do not count toward SUD.
- Conditioned compensatory responses help explain tolerance and overdose in unfamiliar settings (Siegel, Section 4.1).
- Substance-induced disorders include intoxication, withdrawal, and substance-induced mental disorders (such as stimulant-induced psychosis).
- Wernicke-Korsakoff syndrome (thiamine deficiency in chronic alcohol use) produces confusion, ataxia, and eye-movement abnormalities followed by severe anterograde amnesia with confabulation (Section 5.2).
- Gambling disorder (at least 4 of 9 criteria within 12 months) is the only non-substance addictive disorder in the main DSM-5-TR text; Internet gaming disorder is listed in Section III as a condition for further study.
4. Dissociative Disorders
Dissociation is a disruption in the normal integration of consciousness, memory, identity, emotion, perception, and behavior.
- Dissociative identity disorder (DID): Two or more distinct personality states (or an experience of possession) plus recurrent gaps in recall of everyday events, personal information, or trauma. The posttraumatic model links DID to severe childhood trauma; the sociocognitive model (Nicholas Spanos, Scott Lilienfeld) argues that therapist suggestion and cultural scripts shape the presentation. The diagnosis remains controversial.
- Dissociative amnesia: Inability to recall important autobiographical information, usually of a traumatic or stressful nature, that is inconsistent with ordinary forgetting. A dissociative fugue specifier applies when amnesia is accompanied by purposeful travel or bewildered wandering.
- Depersonalization/derealization disorder: Persistent experiences of detachment from oneself (depersonalization) or unreality of surroundings (derealization) with intact reality testing.
5. Somatic Symptom and Related Disorders
| Disorder | Defining Features |
|---|---|
| Somatic symptom disorder | One or more distressing somatic symptoms plus excessive thoughts, feelings, or behaviors about them (disproportionate worry, high anxiety, excessive time and energy); persistent, typically more than 6 months; the symptoms need not be medically unexplained |
| Illness anxiety disorder | Preoccupation with having or acquiring a serious illness, with somatic symptoms absent or mild, for at least 6 months; care-seeking or care-avoidant types (largely replaces DSM-IV hypochondriasis) |
| Functional neurological symptom disorder (conversion disorder) | Altered voluntary motor or sensory function (paralysis, nonepileptic seizures, blindness) with clinical findings incompatible with recognized neurological disease; la belle indifférence is not diagnostic |
| Factitious disorder | Deliberate falsification or induction of physical or psychological signs without obvious external rewards, imposed on self or on another (formerly Munchausen syndrome by proxy) |
| Malingering (not a mental disorder) | Intentional production of symptoms for external incentives such as money, avoiding work, or evading prosecution |
6. Neurocognitive Disorders
- Delirium: An acute disturbance (hours to days) in attention and awareness that fluctuates during the day, with additional cognitive disturbance, caused by a medical condition, intoxication, withdrawal, or medication. It is common in hospitalized older adults and usually reversible when the cause is treated.
- Major versus mild neurocognitive disorder: Major NCD involves significant decline from a previous level in one or more cognitive domains (complex attention, executive function, learning and memory, language, perceptual-motor, social cognition) that interferes with independence in everyday activities. Mild NCD involves modest decline that does not interfere with independence. (DSM-5 replaced the term dementia with major NCD.)
| Etiology | Distinguishing Features |
|---|---|
| Alzheimer's disease | Most common cause; insidious onset, early episodic memory loss; amyloid plaques and tau tangles (Section 10.3); the APOE e4 allele raises risk |
| Vascular NCD | Stepwise or abrupt decline linked to strokes; deficits depend on lesion sites |
| NCD with Lewy bodies | Fluctuating cognition, recurrent well-formed visual hallucinations, parkinsonism, and REM sleep behavior disorder; marked sensitivity to antipsychotics |
| Frontotemporal NCD | Often earlier onset (commonly 45–65); behavioral variant with disinhibition, apathy, and loss of empathy, or language variants such as semantic dementia (Section 5.2) |
| Huntington's and Parkinson's diseases | Subcortical motor disorders with later cognitive decline (Section 1.2) |
7. Disruptive, Impulse-Control, and Conduct Disorders
- Oppositional defiant disorder (ODD): At least 4 symptoms of angry or irritable mood, argumentative or defiant behavior, or vindictiveness for at least 6 months.
- Conduct disorder (CD): At least 3 of 15 criteria in the past 12 months (aggression to people and animals, destruction of property, deceitfulness or theft, serious rule violations); childhood-onset (before age 10) carries a worse prognosis, and a "with limited prosocial emotions" specifier identifies callous-unemotional traits. Conduct disorder before age 15 is required for an adult diagnosis of antisocial personality disorder (Section 12.3).
- Intermittent explosive disorder: Recurrent impulsive aggressive outbursts out of proportion to provocation.
- Disruptive mood dysregulation disorder (DMDD), classified with depressive disorders, involves severe temper outbursts at least three times a week with persistently irritable mood, diagnosed between ages 6 and 18 with onset before age 10. It was added partly to reduce overdiagnosis of pediatric bipolar disorder.
8. Other DSM-5-TR Classes Worth Recognizing
- Prolonged grief disorder (new in DSM-5-TR, 2022): intense yearning for or preoccupation with the deceased, with associated symptoms, at least 12 months after the death for adults (6 months for children and adolescents).
- Sleep-wake disorders: insomnia, narcolepsy, and REM sleep behavior disorder (Section 3.1).
- Gender dysphoria: clinically significant distress associated with incongruence between experienced gender and assigned gender.
- Paraphilic disorders: DSM distinguishes a paraphilia (an atypical sexual interest) from a paraphilic disorder, which requires distress, impairment, or harm or risk of harm to others.
- Elimination disorders: enuresis is diagnosed only from age 5 (chronological or developmental).
A 22-year-old has binged on large amounts of food about twice a week for the past six months, each time feeling out of control. She does not vomit, fast, use laxatives, or exercise excessively, and her BMI is 27. Which diagnosis fits best?
Binge-eating disorder
Anorexia nervosa, binge-eating/purging type
Avoidant/restrictive food intake disorder
Bulimia nervosa
Over the past year, a man has repeatedly used more alcohol than he intended, tried and failed to cut down, and needed increasing amounts to feel an effect. No other criteria are met. How is this classified under DSM-5-TR?
Mild alcohol use disorder
No diagnosis, because withdrawal is required
Severe alcohol use disorder, because tolerance is present
Alcohol abuse, because physiological dependence is absent
An elderly hospitalized patient becomes confused over two days after starting a new medication. Her attention wanders, she is disoriented at night but more lucid in the morning, and she has no prior history of cognitive decline. Which diagnosis is most likely?
Mild neurocognitive disorder
Major neurocognitive disorder due to Alzheimer's disease
Delirium
Dissociative amnesia
A woman repeatedly injects herself with contaminated water to produce infections and seek hospital care. She has no financial or legal incentive and hides her actions from staff. Which diagnosis best fits?
Functional neurological symptom disorder
Factitious disorder imposed on self
Malingering
Illness anxiety disorder
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