Complex Comorbid Presentations are Associated with Harmful Behavior Problems among Children and Adolescents with Cerebral Palsy.

: Frequency and relationship between gastrointestinal symptoms, sleep problems, internalizing and externalizing symptoms, behavior problems and autism spectrum disorder (ASD) symptoms, and predictors of behavior problems were examined in children and adolescents with Cerebral Palsy (CP). : Parents of 104 children and adolescents with CP completed the Gastrointestinal Symptom Inventory, Children's Sleep Habits Questionnaire, Child Behavior Checklist, Social Communication Questionnaire and the Behavior Problem Inventory-Short Form. : High frequency of behavior problems (88.5%), gastrointestinal symptoms (81.7%), sleep problems (81%) ASD symptoms (48%) and internalizing and externalizing symptoms (31.7%) were found. Relationships were found between gastrointestinal symptoms and sleep problems, and gastrointestinal symptoms and internalizing and externalizing symptoms. Relationships were found between sleep problems and behavior problems. Intellectual disability, sleep problems, internalizing and externalizing symptoms, and ASD symptoms predicted behavior problems. : Findings highlights the frequency of comorbidities that exist in CP and how these comorbidities affect one another.