Obsessions and compulsions

Obsessions are recurrent, persistent, intrusive and unwanted thoughts, images or urges that cause marked anxiety or distress.

Compulsions are repetitive behaviours (washing, checking, ordering, counting) or mental acts (praying, repeating words silently). They are performed in response to an obsession or by rigid rules, to reduce distress or prevent a feared event. They are excessive or not realistically connected to what they aim to prevent.

The presentation is obsessive compulsive disorder (OCD) in most patients, but similar symptoms occur in other psychiatric disorders, neurological disease, infection related syndromes and drug effects.

Definitions. Diagnostic criteria for OCD: obsessions, compulsions or both, taking more than 1 hour daily or causing clinically significant distress or impairment, not attributable to a substance or medical condition, and not better explained by another mental disorder. Insight is specified as good or fair, poor, or absent (delusional beliefs). A tic related specifier applies when there is a current or past tic disorder. Classification

• Symptom dimensions: contamination and cleaning, symmetry and ordering, forbidden or taboo thoughts (aggressive, sexual, religious), harm and checking, and hoarding. Dimensions overlap and change over time.
• Related disorders: body dysmorphic disorder, hoarding disorder, trichotillomania (hair pulling), excoriation (skin picking) disorder, illness anxiety disorder, olfactory reference syndrome.
• Secondary obsessive compulsive disorder due to a medical condition or substance: basal ganglia disease, traumatic brain injury, stroke, encephalitis, paediatric acute onset neuropsychiatric syndromes (PANS, PANDAS), and drug induced (clozapine, olanzapine, risperidone, levodopa, dopamine agonists, lithium).
• Obsessive compulsive personality disorder: a pervasive pattern of perfectionism, orderliness and control that is ego syntonic and does not involve intrusive unwanted thoughts.
• Other disorders with repetitive thoughts or behaviours: generalised anxiety (worries are about real life concerns), depressive rumination, psychosis, autism (repetitive behaviours, special interests), eating disorders, tic disorders and Tourette syndrome, and posttraumatic stress disorder.

Epidemiology. OCD affects 1% to 3% of people over a lifetime. Onset is bimodal, with peaks in childhood (before age 10 years, more often boys) and late adolescence to early adulthood, and a mean age of onset of about 19 years. The delay from onset to treatment averages 7 to 10 years. Comorbidity is common: depression (about 60%), anxiety disorders, tic disorders (about 30% in early onset), bipolar disorder, eating disorders, ADHD, autism and substance use. Suicidal thoughts occur in about half of patients and attempts in 10% to 25%.

Mechanisms. Dysfunction of cortico-striato-thalamo-cortical circuits (orbitofrontal cortex, anterior cingulate, caudate), altered serotonin, dopamine and glutamate signalling, genetic factors (heritability 40% to 50%), and cognitive factors (inflated responsibility, thought action fusion, intolerance of uncertainty, overestimation of threat). Compulsions reduce anxiety briefly, which reinforces them.

Key distinctions. Intrusive thoughts that the patient finds abhorrent and unwanted with resisted rituals point to OCD. Worries about real events without rituals point to generalised anxiety. Thoughts experienced as imposed from outside with delusional belief point to psychosis. Fixed concern about illness with repeated reassurance seeking and doctor visits points to illness anxiety.

Ritual acts that feel pleasurable and are not distressing suggest a personality style, not OCD. Sudden onset in a child after streptococcal infection suggests PANDAS. Repetitive movements without a preceding thought suggest tics or stereotypies.

History

• Obsessions: ask directly and without judgement about intrusive thoughts (contamination, harming others, accidents, unwanted sexual or blasphemous thoughts, need for symmetry, doubts), the content, frequency, and distress. Ask "Do you have unpleasant thoughts that you cannot get out of your head?" and "Do you feel driven to repeat actions?"
• Compulsions: washing (hand washing times, products used, skin damage), checking (doors, appliances, switches, driving), ordering, counting, repeating, hoarding, mental rituals, reassurance seeking, and avoidance.
• Time: hours spent each day on obsessions and rituals, interference with work, school, relationships and self care, and effect on family accommodation (family members taking part in rituals).
• Onset and course: age at onset, triggers (childbirth, bereavement, stress, illness), fluctuation, and previous treatment with doses and duration.
• Insight: whether the patient believes the feared consequence would happen.
• Comorbidity: depression, anxiety, tics, eating disorder, body dysmorphic disorder, trauma, bipolar disorder, psychosis, substance and alcohol use.
• Suicidal thoughts, self harm, and fear of harming others (in OCD this is unwanted and the patient is horrified, with very low risk of acting).
• Perinatal: onset in pregnancy or after delivery (intrusive thoughts of harm to the baby, with avoidance).
• Medical and neurological: head injury, stroke, encephalitis, epilepsy, rheumatic fever, recent streptococcal infection, abrupt onset in a child, and movement disorder.
• Drugs: antipsychotics (clozapine, olanzapine, risperidone, quetiapine), levodopa, dopamine agonists, stimulants, lithium, and steroids.
• Family history of OCD, tics, anxiety, and depression.

Examination

• General appearance: hand dermatitis and cracked skin from washing, hair loss from pulling, skin lesions from picking, weight, and neglect.
• Mental state: observe rituals, avoidance, reassurance seeking, mood, anxiety, psychotic features, insight, and suicidal thoughts.
• Neurological: tics, choreiform movements, tone, tremor, gait and focal signs (basal ganglia disease).
• Rating scales: Yale-Brown Obsessive Compulsive Scale (Y-BOCS, 0 to 40: 8 to 15 mild, 16 to 23 moderate, 24 to 31 severe, 32 to 40 extreme), Children's Yale-Brown scale, Obsessive-Compulsive Inventory-Revised (score of 21 or more suggests OCD), PHQ-9, GAD-7, and Dimensional Obsessive-Compulsive Scale.
• Child with sudden onset: throat examination, joints, skin, cardiac murmur, and neurological examination.

Red flags

• Suicidal ideation, intent or plan.
• Psychotic symptoms or loss of insight (delusional conviction).
• Severe self neglect: not eating, drinking or leaving the home; severe weight loss or dehydration.
• Severe skin damage, infection or bleeding from compulsive washing, picking or pulling.
• Hoarding with fire risk, blocked exits, infestation or health hazard.
• Abrupt onset in a child or adolescent (hours to days) with food refusal, tics, mood lability and separation anxiety (PANS, PANDAS).
• New onset in middle age or later without psychiatric history (neurological disease, tumour, stroke, dementia).
• Focal neurological signs, seizures or cognitive decline.
• Postpartum obsessions with psychosis, confusion or delusions about the baby (postpartum psychosis).
• Severe depression, mania, eating disorder or substance dependence.
• Children with severe family disruption or safeguarding concerns.

Special groups

• Children: rituals may be hidden or be done with parents. Ask parents about family accommodation. Assess school function and bullying.
• Adolescents: secrecy and shame are common. Ask about internet use and sexual or aggressive obsessions.
• Pregnancy and postpartum: intrusive harm thoughts are common (up to 70% of new mothers) and distinguishable from psychosis by distress and absence of intent. Reassure and treat.
• Older adults: new onset suggests neurological disease or depression. Hoarding is more common.
• Chronic disease: contamination fears in infection, health anxiety in cancer.
• Cultural and religious factors: religious rituals (prayer, ablutions) may be normal, but excess and distress distinguish OCD (scrupulosity). Ask about local norms and beliefs.

Obsessive compulsive and related disorders

• Obsessive compulsive disorder (contamination, symmetry, harm, taboo thoughts, hoarding).
• Body dysmorphic disorder and olfactory reference syndrome.
• Hoarding disorder.
• Trichotillomania and excoriation disorder.
• Illness anxiety disorder.

Other psychiatric disorders

• Generalised anxiety disorder (worries without rituals).
• Major depressive disorder (ruminations).
• Social anxiety disorder and specific phobia (avoidance without compulsions).
• Posttraumatic stress disorder (intrusive memories, avoidance).
• Psychotic disorders (delusions, thought insertion, ritualised behaviour in schizophrenia).
• Autism spectrum disorder (repetitive behaviours, routines, special interests, sensory needs).
• Tourette syndrome and tic disorders (premonitory urge but no cognitive obsession).
• Anorexia nervosa and bulimia nervosa (food rituals).
• Obsessive compulsive personality disorder.
• Bipolar disorder (obsessive symptoms in depression, racing thoughts).
• Substance use disorders and gambling disorder.
• Perinatal intrusive thoughts and postpartum psychosis.
• Adjustment disorder and normal intrusive thoughts and superstitions.

Neurological and medical causes

• Basal ganglia disorders (Huntington disease, Parkinson disease, Wilson disease, Sydenham chorea).
• Traumatic brain injury, stroke, and tumour (frontal, caudate).
• Frontotemporal dementia (compulsive behaviours).
• Epilepsy (temporal lobe).
• Encephalitis (autoimmune, infectious), PANS and PANDAS.
• Kleine-Levin syndrome and Prader-Willi syndrome (hyperphagia and compulsions).
• Hyperthyroidism and hypothyroidism.
• Systemic lupus erythematosus and neuropsychiatric lupus.

Drug induced

• Clozapine, olanzapine, risperidone, quetiapine and aripiprazole.
• Levodopa and dopamine agonists (pramipexole, ropinirole).
• Stimulants and cocaine.
• Lithium, corticosteroids, and some antiepileptics.

Step 1. Assess risk and exclude emergencies. Evaluate suicidal thoughts, self neglect, medical complications and safeguarding. Identify psychosis, mania, delirium or abrupt childhood onset.

Step 2. Make a clinical diagnosis. Confirm obsessions and compulsions, time taken (over 1 hour daily), distress and impairment, and exclusion of other disorders. Use the Y-BOCS symptom checklist and severity scale. Screen for depression, anxiety, tics, autism, ADHD, eating disorder, and substance use. Assess insight and family accommodation.

Step 3. First line tests. There is no diagnostic test for OCD. Do the following when clinically warranted or before drug treatment.

• Full blood count, electrolytes, urea, creatinine, liver tests, thyroid stimulating hormone, glucose, and vitamin B12.
• Urine toxicology if substance use is suspected.
• Pregnancy test in women of reproductive age.
• ECG before citalopram, escitalopram, clomipramine (QTc, conduction) and when cardiac risk is present.
• Sodium before and 2 weeks after starting an SSRI in older adults (risk of hyponatraemia).

Step 4. Targeted tests

• MRI brain for late onset (over 40 years), focal signs, seizures, abrupt change, or cognitive decline.
• Electroencephalogram if seizures or altered awareness.
• Copper, caeruloplasmin and slit lamp examination (Kayser-Fleischer rings) in young adults with movement disorder.
• Throat swab, antistreptolysin O and anti-DNase B titres in children with abrupt onset and recent sore throat; consider autoimmune antibodies and lumbar puncture when encephalitis is suspected.
• Antinuclear antibodies and complement in suspected lupus.
• Genetic and neurological referral for Huntington disease with family history.
• Neuropsychological testing when cognitive decline is possible.

Step 5. Interpretation. Diagnose OCD when obsessions and compulsions are present, time consuming or impairing, and not due to substance or medical disease. Symptoms that are ego syntonic and lack distress suggest personality style. Delusional conviction suggests psychosis. Abrupt onset in a child needs exclusion of PANS and PANDAS, but diagnosis relies on clinical features.

Limits. Scales assess severity but do not replace clinical interview. Patients under report symptoms, so direct questions are needed. Antistreptolysin O titres are raised in many healthy children, so a single result does not prove PANDAS.

Immediate. Assess and manage suicide risk. Explain that intrusive thoughts are common, are a symptom of illness, and do not mean the patient will act on them. Treat any acute medical complication (skin infection, dehydration, malnutrition). Withdraw or substitute offending drugs. Remove fire and safety hazards in hoarding.

Psychological treatment (first line for all severities)

• Cognitive behavioural therapy with exposure and response prevention: 12 to 20 weekly sessions of 60 to 90 minutes (adults), with homework between sessions, graded exposure to feared situations, and prevention of rituals.
• Intensive formats over 1 to 3 weeks and group or online therapy are effective. Response (a Y-BOCS fall of 35% or more) is seen in about 50% to 60%.
• Children: family based cognitive behavioural therapy with exposure and response prevention (12 to 14 sessions), with parents trained to reduce accommodation.
• Family education and reduction of accommodation.

Pharmacological treatment (moderate to severe disease, or when psychological therapy is unavailable or failed; doses are higher than in depression, with response taking 8 to 12 weeks)

• Sertraline 25 to 50 mg orally once daily (25 mg for the first week), increased every 1 to 2 weeks by 50 mg to 200 mg (maximum 200 mg daily; in some settings 400 mg under specialist care).
• Fluoxetine 20 mg once daily, increased after 2 to 4 weeks to 40 to 60 mg (maximum 80 mg daily under specialist care).
• Fluvoxamine 50 mg at night, increased every 4 to 7 days by 50 mg to 200 to 300 mg daily (maximum 300 mg; divide doses over 150 mg). Interacts with many drugs through CYP1A2 and CYP2C19 inhibition (theophylline, warfarin, clozapine, tizanidine, caffeine).
• Paroxetine 20 mg daily, increased by 10 mg weekly to 40 to 60 mg (maximum 60 mg).
• Escitalopram 10 mg daily, increased to 20 mg (maximum 20 mg; 10 mg over 65 years). Citalopram 20 mg increased to 40 mg (maximum 40 mg, 20 mg over 65 years or in hepatic impairment) with QTc monitoring.
• Clomipramine 25 mg at night, increased by 25 mg every 3 to 4 days to 100 to 150 mg and then to 250 mg daily (maximum 250 mg) in divided doses or at night.
• Reserve clomipramine for patients not responding to at least one SSRI. Check ECG, avoid in recent myocardial infarction and arrhythmia, and monitor for anticholinergic effects, seizures, and serotonin syndrome. Plasma level monitoring is useful when combined with fluvoxamine.
• Adequate course of each drug: at least 8 to 12 weeks at maximum tolerated dose. If there is partial or no response, switch to another SSRI or clomipramine, then augment.
• Augmentation (specialist): risperidone 0.5 mg at night increased to 1 to 3 mg daily, or aripiprazole 2.5 to 5 mg increased to 10 to 15 mg, or quetiapine 25 to 50 mg increased to 150 to 300 mg, for at least 8 weeks.
• Alternatives: memantine 5 mg daily increased weekly to 20 mg, n-acetylcysteine 600 to 3000 mg daily, or clomipramine added to an SSRI under supervision. Monitor weight, glucose, lipids and QTc.
• Children and adolescents (7 years and over): sertraline 25 mg daily (6 to 12 years) or 50 mg (12 years and over) increased weekly to 50 to 200 mg.
• Fluoxetine 10 mg daily for 1 to 2 weeks then 20 mg (maximum 60 mg). Fluvoxamine 25 mg at night increased every 4 to 7 days to 50 to 200 mg (maximum 200 mg in children 8 to 11 years, 300 mg in adolescents).
• Monitor children and adolescents for suicidal thoughts and activation, especially in the first weeks and after dose changes.
• Duration: continue the effective dose for at least 12 months after remission (often 1 to 2 years), then taper over 3 to 6 months or longer, since relapse after stopping is common (up to 50% or more). Longer treatment is used for severe or relapsing disease.
• Common adverse effects: nausea, headache, insomnia, sexual dysfunction, weight change, and hyponatraemia in older adults. Starting dose is low to reduce jitteriness.

Resistant disease (specialist)

• Intensive inpatient or residential therapy.
• Transcranial magnetic stimulation (deep, over the prefrontal cortex and anterior cingulate) for adults who have failed drugs and therapy.
• Deep brain stimulation or gamma knife capsulotomy for severe, disabling, treatment resistant disease.

Treatment of specific forms and conditions

• PANS and PANDAS: treat obsessive compulsive symptoms with cognitive behavioural therapy and SSRI at low dose.
• Treat active streptococcal infection in PANS and PANDAS with phenoxymethylpenicillin (children: 250 mg twice daily for 10 days; adults 500 mg four times daily for 10 days). Consider immunomodulatory treatment under specialist care.
• Comorbid tics: add habit reversal and consider aripiprazole 2 to 5 mg.
• Comorbid depression, anxiety, eating disorder, or bipolar disorder: treat accordingly. Avoid SSRI monotherapy in bipolar disorder.
• Body dysmorphic disorder: same psychological and drug approach with higher doses and longer treatment.
• Hoarding disorder: cognitive behavioural therapy for hoarding (26 sessions), home visits and decluttering support. SSRIs and venlafaxine have modest effect.
• Trichotillomania and skin picking: habit reversal therapy and n-acetylcysteine 1200 to 2400 mg daily.
• Perinatal OCD: psychological therapy first. Sertraline can be used in pregnancy and breastfeeding when needed.
• Skin damage from washing: emollients, topical corticosteroids (hydrocortisone 1% twice daily for 1 week), and antibiotic for infection.

Special populations

• Pregnancy and breastfeeding: prefer psychological therapy, and use sertraline when drug treatment is needed. Avoid paroxetine in pregnancy and clomipramine near delivery without specialist input.
• Older adults: start at half the usual dose, check sodium, and avoid clomipramine and paroxetine (anticholinergic effects).
• Hepatic and renal impairment: lower doses of SSRIs (halve the dose in severe liver disease), avoid fluvoxamine interactions, and check levels of clomipramine.

Monitoring. Y-BOCS every 4 to 8 weeks, suicidal thoughts (especially in the first 4 weeks and under 25 years), adverse effects, weight, sodium in older adults, ECG for citalopram, escitalopram and clomipramine, adherence, and family accommodation.

Referral and escalation. Psychiatry or specialist OCD services for moderate to severe disease, comorbidity, poor insight, and no response to 2 adequate drug courses or cognitive behavioural therapy. Neurology or paediatric neurology for abrupt onset or neurological signs. Dermatology for skin damage. Dietetic and eating disorder services as indicated.

Admission criteria. Suicidal intent, severe self neglect with dehydration or malnutrition, psychosis, postpartum psychosis, inability to function despite outpatient care, or severe skin infection.

Discharge and follow up. Written plan, explanation of exposure therapy, review at 2 to 4 weeks after starting drugs, then every 4 to 8 weeks until stable. Safety net advice: return for suicidal thoughts, inability to eat or drink, fever with skin infection, new psychotic beliefs, or abrupt worsening in a child.