Updated: 6/28/2020

Obsessive-Compulsive Disorder

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  • A 16-year-old boy presents to the clinic for an itchy rash on his hands. He reports he is concerned because of an ongoing pandemic, and he cannot help but wash his hands every hour while awake, even if he did not leave the house or touch anything dirty. He reports being very preoccupied with thoughts of having “dirty” hands filled with microorganisms and feels partial relief when he washes his hands thoroughly with soap and water. On exam, he has pink scaly plaques on his hands and tiny vesicles along the lateral fingers, consistent with hand dermatitis. He is prescribed a strong topical steroid cream and referred to psychiatry for management of suspected obsessive-compulsive disorder.
  • Overview
    • obsessive-compulsive disorder (OCD) is characterized by obsessive intrusive thoughts, sensations, or feelings that may be relieved by repetitive compulsive mental or physical actions
      • treatment is usually cognitive behavioral therapy or medications
  • Epidemiology
    • incidence
      • common, with a lifetime prevalence of 1.7-4%
    • demographics
      • males are more likely to have onset in adolescence and to have a comorbid tic disorder
    • risk factors
      • family history
  • Pathogenesis
    • mechanism
      • exact pathogenesis is unclear but research suggests that there are abnormalities in serotonin neurotransmission
      • twin studies also show a genetic influence, although a genetic mutation has not been identified
      • ego dystonic
        • behavior inconsistent with one's own beliefs and attitudes
          • separates OCD from obsessive-compulsive personality disorder
  • Associated conditions
    • patients often have other psychiatric comorbidities, including mood and anxiety disorders 
    • associated with Tourette disorder, increased activity of the caudate nucleus  
  • Prognosis
    • symptoms wax and wane, even with treatment
  • Symptoms
    • obsessions and compulsions often occupy hours a day and interfere with daily life
    • recurrent and persistent intrusive thoughts (obsessions)
      • common obsessions include fear of contamination, need for symmetry, unwanted sexual thoughts, and doubts
      • causes anxiety and distress
    • repetitive behaviors (compulsions)
      • hand washing
      • putting items in order
      • checking and rechecking tasks
  • Physical exam
    • hand dermatitis
      • related to excessive hand washing
    • patchy hair loss
      • related to compulsive hair pulling or trichotillomania
    • excoriations or prurigo nodules
      • related to compulsive skin picking
  • Yale-Brown Obsessive Compulsive scale
    • to evaluate range and severity of symptoms
    • to monitor treatment response
  • Intrinsic atopic dermatitis
    • key distinguishing factors
      • treatment with topical steroids can help resolve rash
      • treatment with cognitive behavioral therapy and control of compulsions may not result in resolution of rash
  • Body dysmorphic disorder
    • key distinguishing factors
      • preoccupation with a perceived defect in one’s appearance, causing significant distress, and dysfunction
      • treatment with cognitive behavioral therapy
  • Lifestyle
    • cognitive behavioral therapy (CBT)
      • indications
        • all patients
        • some patients may not need pharmacologic treatment with successful behavioral therapy
  • Medical
    • serotonin selective reuptake inhibitors (SSRIs)
      • indications
        • first-line
        • often in addition to CBT
    • tricyclic antidepressant
      • indication
        • second-line
  • Continued psychologic distress and functional impairment

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Questions (5)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2

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(M1.PY.15.73) A 27-year-old male presents to the psychiatrist requesting help with his compulsions as they are interfering with his life. He explains that he has this fear that something terrible will happen to his house if he does not check every appliance, outlet, window and door lock, faucet, and light fixture before he leaves. He states that he must check everything 7 times in a specific order and if he goes out of order he must start from the beginning and perform it all over. He has recently been fired from his job because he is always late and lost his fiancee as she could not deal with his habits anymore. The physician explained that cognitive-behavioral therapy may be of assistance and also prescribed clomipramine. Which of the following is the mechanism of reaction of clomipramine? Review Topic | Tested Concept

QID: 106601

Decreases the degradation of norepinephrine and serotonin




Increases the release of norepinephrine and serotonin by alpha 2 receptor antagonism




Blocks only norepinephrine reuptake




Blocks reuptake of norepinephrine and serotonin




Increases presynaptic release of norepinephrine and dopamine from vesicles



L 1 B

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