Key concepts: OCD and related disorders

OCD: prevalence, onset, course, and comorbidity

  • Prevalence: 1.2%1.2\% of US adults per year; lifetime prevalence 2.3%2.3\%.
  • Age of onset by sex: males 6−15 yrs6-15\text{ yrs}; females 20−29 yrs20-29\text{ yrs}.
  • Adulthood: females rate slightly higher than males.
  • Childhood pattern: OCD prevalence 2−4%2-4\%; mean onset 7.5−12.5 yrs7.5-12.5\text{ yrs}; sex ratio reversed in childhood (more males); by mid‑adolescence roughly equal; then predominantly female in adulthood.
  • Course: typically chronic with symptoms that ebb and flow.
  • Comorbidity: high with anxiety and mood disorders; also impulse‑control and substance use disorders; major depressive disorder comorbidity about 66%66\%.
  • Global perspective: worldwide lifetime prevalence 1−3%1-3\%; many exhibit subthreshold symptoms.
  • Cross‑national: European Americans show higher rates than African Americans or Hispanic Americans; prevalence generally similar across nations studied (US, Canada, Mexico, England, Norway, Hong Kong, India, Egypt, Japan, Korea).
  • Note: OCD can present with compulsive checking and distressing obsessions; symptoms may be hiding or undetected in youth.

Hoarding Disorder: DSM-5-TR criteria and distinctions from OCD

  • Hoarding is a separate DSM‑5‑TR diagnosis (not merely a facet of OCD) due to distinct features and biology.
  • Core features: persistent difficulty discarding possessions, regardless of value; distress associated with discarding; accumulation causes clutter and impairs use of living spaces; clinically significant distress/impairment; not attributable to another medical condition or another mental disorder.
  • Specifiers:
    • With excessive acquisition
    • With good or fair insight
    • With poor insight
    • With absent insight/delusional beliefs
  • Distinction from OCD: thoughts about possessions are not intrusive/distressing in the same way; hoarding may create a nest/cocoon and provokes anxiety if pressured to discard.
  • Prevalence and impact: hoarding disorder occurs in up to 5%5\% of the US population; high comorbidity with depression, social anxiety, generalized anxiety.

Other OCD‑spectrum disorders: Trichotillomania and Excoriation

  • Trichotillomania (hair‑pulling disorder): repetitive pulling leading to hair loss; automatic vs focused pulling.
  • Prevalence: 0.5−2.0%0.5-2.0\%.
  • Sex and onset: adults—female to male ratio ≈ 4:1; childhood—sex distribution roughly equal; average onset 10−13 yrs10-13\text{ yrs}.
  • Excoriation (skin‑picking disorder): repetitive skin picking.
  • Prevalence: 2−5%2-5\%; often begins in adolescence; commonly targets acne lesions or healthy skin.

Body Dysmorphic Disorder (BDD)

  • Definition: obsessive–compulsive spectrum disorder with excessive preoccupation about perceived physical flaws causing marked distress/impairment.
  • Common preoccupations: skin, hair, nose, eyes, eyelids, mouth, lips, jaw, chin; typically multiple areas (average ~4).
  • Compulsions: mirror checking, touching, inspecting/disliking areas, excessive grooming, reassurance seeking, comparing with others, camouflage with makeup/clothing; can spend 3−8 hours/day3-8\text{ hours/day} on preoccupations.
  • Insight: reassurance does not alleviate distress; specifier may be absent insight/delusional beliefs.
  • Onset and course: often begins in adolescence; average onset age ≈ 16 yrs16\text{ yrs};>70%70\% before age 18; tends to be chronic if untreated.
  • Prevalence by sex: males 2.5%2.5\%; females 2.2%2.2\%.
  • Comorbidity: high with anxiety disorders, depressive disorders, personality disorders, substance use; especially comorbid with OCD.
  • Gender differences in concerns reflect cultural norms: women—face/weight/stomach/breasts; men—body build/genitals/excessive body hair/thinning hair.
  • Social media and culture: excessive selfie use linked to appearance concerns; time on social media correlates with age and amount of use; appearance comparisons and internalization of ideal bodies can maintain or exacerbate BDD.
  • Subclinical risk: high social media exposure may contribute to subthreshold BDD symptoms and vulnerability to develop full syndrome.
  • Delusional beliefs: some individuals hold beliefs with absent insight/delusional beliefs; delusions are not the same as psychosis.
  • Cosmetic surgery caution: cosmetic procedures are not advised and can worsen preoccupations.
  • Muscle dysmorphia (MD): a BDD specifier in men; describes a perception of being small/weak despite typical muscle mass; behaviors include excessive weightlifting, dieting, and drug use (often called reverse anorexia).
  • Suicidality: BDD associated with high risk; lifetime suicidal ideation ≈ 80%80\% and suicide attempts ≈ 21.5−28%21.5-28\%; completed suicides less well defined but risk is high.
  • Relationship to eating disorders: if preoccupations with weight/shape are part of an eating disorder, BDD is not diagnosed.

Biological theories and OCD‑related disorders

  • Etiology: OCD/OC spectrum disorders are multifactorial with strong genetic components.
  • Neural circuitry: a frontal–basal ganglia–thalamic loop involving the caudate/putamen, thalamus, anterior cingulate cortex (ACC), and frontal cortex.
  • Shared abnormalities: OCD, trichotillomania, and excoriation show alterations in this circuit and connectivity.
  • Hoarding: related to alterations in other frontal and limbic regions rather than the classic OCD circuit.
  • BDD: brain activity differences during processing of visual stimuli (e.g., faces) compared to controls.
  • DSM‑5‑TR consolidation: trichotillomania and excoriation included with OCD/hoarding due to shared features like repetitiveness, inhibition problems, and pre‑urge tension with relief upon giving in.

Summary points for quick recall

  • OCD: common, chronic, with early onset in males; strong comorbidity with anxiety, mood disorders; depression present in many cases.
  • Hoarding: separate DSM‑5‑TR disorder; significant clutter/disorganization; distinctive specifiers and a high, but distinct, comorbidity profile.
  • Trichotillomania and excoriation: OC spectrum disorders with similar features and comorbidity patterns.
  • BDD: severe appearance concerns with substantial impairment; high suicidality; strong link to social media and appearance comparisons; not merely “body dissatisfaction.”
  • MD: a BDD specifier in men; focus on being too small/weak.
  • Neurobiology: OCD/OC disorders involve a frontal–basal ganglia–thalamus–ACC circuit; hoarding uses different frontal/limbic regions; BDD involves abnormal visual processing.