"How many times per day do you wash your hands?" to quantify the ritual frequency, as the total number of daily compulsions is the primary metric for determining OCD severity and treatment threshold.

Frequency alone does not capture OCD severity. A patient who washes 10 times but each wash takes 15 minutes with high distress may be more impaired than a patient who washes 20 times quickly with less distress.

"How much distress do you feel if you try to resist the handwashing, and how much does it interfere with your daily activities?" to assess the core CY-BOCS dimensions that determine severity and guide treatment planning.

OCD severity is measured by distress upon resistance and functional interference — these are the core dimensions assessed by the CY-BOCS (Children's Yale-Brown Obsessive Compulsive Scale), the gold standard for pediatric OCD severity. The CY-BOCS assesses: time occupied, interference with functioning, distress, resistance, and degree of control over symptoms. These dimensions guide treatment decisions — moderate-to-severe OCD in children warrants CBT with ERP (exposure and response prevention) as first-line, with SSRI augmentation if CBT alone is insufficient.

"When did the handwashing start?" to establish the onset and timeline of symptoms, as the duration of untreated OCD is a key prognostic indicator that determines whether CBT or medication is the preferred first-line treatment.

Onset timing is relevant history but does not determine current severity or treatment urgency. Duration of illness does not dictate the choice between CBT and medication in pediatric OCD guidelines.

"Does anyone else in your family wash their hands excessively?" to assess for familial OCD patterns, as a positive family history of OCD significantly changes the treatment approach and prognosis in pediatric patients.

Family history provides context and supports a genetic component but does not assess the child's current symptom severity or directly change the treatment algorithm for this patient.