Childhood-onset OCD — ERP, POTS and SSRI monitoring (MEQ)

(i) Diagnosis and differentials. Working diagnosis: obsessive-compulsive disorder, childhood-onset, multi-dimensional (contamination/washing, symmetry/rewriting, checking) with marked time cost and impairment, good-to-fair insight suggested by shame/ego-dystonic tone of harm thoughts. Not primarily psychotic. Differentials: ASD routines (less fitting ego-dystonic anxiety here), complex tics (screen for tic-related specifier), GAD, illness anxiety, depression, body-focused OCRDs if relevant. PANDAS/PANS less likely with gradual multi-year course and no acute post-infectious story — mention concept without forcing work-up as default.[3][7]

(ii) Assessment. Multi-informant history of content, hours, avoidance, school impact, risk (self-harm, harm-obsessions distress, neglect of self-care). Inventory family accommodation (reassurance, participation, restricted outings).[6] Screen tics, ADHD, mood, ASD traits, substances, safeguarding/bullying. Use CY-BOCS for severity baseline and tracking.[4] Shared formulation with youth and carers.

(iii) Stepped management. Psychoeducation: OCD loop, not wilful; reduce accommodation as treatment target. First-line psychological: CBT with ERP — hierarchy, exposure without rituals (including mental reviewing and reassurance), homework, carer coaching; evidence supports CBT effect sizes in paediatric meta-analysis.[9][3] For this moderate–severe multi-hour presentation, discuss SSRI concurrent or sequential: e.g. sertraline start approximately 25 mg oral daily, titrate toward paediatric OCD ranges often up to about 50–200 mg/day; alternatives fluoxetine (e.g. 10 then 20 mg, titrate toward ~20–60 mg) with black-box suicidality/activation monitoring, early review, carer education. Adequate trial ~8–12 weeks at therapeutic dose. Verify local PI.[5][8][3]

(iv) POTS / POTS II. POTS: CBT and sertraline each beat placebo; combination particularly effective for severe illness — justifies combined pathway here.[1] POTS II: if partial SRI response, add/intensify CBT rather than medication management alone.[2] (Note POTS Jr if examiner asks about under-8s — family-based CBT.)[10]

(v) School and risk. Risk assess forbidden-harm thoughts (ego-dystonic vs intent), suicide/self-harm, skin breakdown, school refusal. School plan: gradual return, bathroom timing accommodations without enabling endless washing, anti-bullying, staff psychoeducation. Written crisis contacts; follow-up for ERP and medication titration.[3]