Inclusion Criteria:  OCD (ICD-10 F42) as the primary or secondary diagnosis, verified with a semi-structured psychopathological interview using K-SADS-PL. CY-BOCS > 7: mild (8-15), moderate (16-23), severe (24-31), extreme (32-40) A psychiatrist determined that the child is eligible for care within psychiatry for their primary diagnosis. Patient is age 8 through 17 years (both inclusive). Signed informed consent.  Exclusion Criteria:  Participation in other OCD trials. Comorbid illness that contraindicates trial participation: pervasive developmental disorder not including Asperger's syndrome (ICD-10 F84.0-84.4 + F84.8-84.9)), schizophrenia/paranoid psychosis (ICD-10 F20-25 + F28-29), mania or bipolar disorder (ICD-10 F30 and F31), depressive psychotic disorders (F32.3 + F33.3), substance dependence syndrome (ICD-10 F1x.2). Intelligence Quotient <70. Any condition (e.g. allergies, eczema, hypersensitivity due to Asperger's syndrome) that would prevent the child or parent from wearing a wristband biosensor.