Pharmacogenetic Considerations in Sertraline Augmentation With Quetiapine in an Adolescent Woman With Obsessive-Compulsive Disorder, Autism Spectrum Disorder, and Attention-Deficit Hyperactivity Disorder: A Case Report.

Obsessive compulsive disorder (OCD) in children and young people commonly presents alongside neurodevelopmental comorbidities such as autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD). These presentations are often associated with greater functional impairment and pose significant diagnostic and treatment challenges. We describe the case of an adolescent woman with OCD, ASD, and ADHD who presented with a deterioration in her mental state, characterised by symmetry-related grooming and self-care rituals lasting up to four hours daily, low mood, poor sleep, social withdrawal, suicidal ideation, and marked impairment in daily functioning. She had previously been stabilised on sertraline (200 mg) and lisdexamfetamine (60 mg). Worsening symptoms and functional decline raised the possibility of benefit from antipsychotic augmentation, and quetiapine was initiated. This was guided by pharmacogenetic testing following a poor initial response to ADHD medication and adverse effects when sertraline was first commenced. After three months of treatment with quetiapine, she demonstrated functional improvement, including a reduction in symmetry rituals and improved social engagement. This case highlights the complexities of psychological and pharmacological management of OCD in the context of neurodevelopmental comorbidity. Improved understanding of precision psychiatry in OCD with ASD comorbidity may facilitate the development of more tailored treatment approaches, including neurodevelopmentally adapted psychological interventions and targeted pharmacological strategies.