RESUMEN
BACKGROUND: Co-occurring problems are common in individuals with clinical autism spectrum disorder (ASD) but their relevance for impairment and contact with health services in ASD is largely unexplored. AIMS: We investigated the extent of co-occurring problems in children with high ASD traits from a total population sample. We explored the contribution of co-occurring problems to impairment and service contact, and whether there were children without co-occurring problems in this group; as proxy for "ASD only". METHODS AND PROCEDURES: Children screening positive on the Autism Spectrum Screening Questionnaire (ASSQ) were used as proxy for ASD. Attention Deficit/Hyperactivity Disorder (ADHD) and Oppositional Defiant Disorder (ODD) were operationalised using symptom counts. A parent or teacher report above the 95th percentile counted as "problem" present for other symptom domains. OUTCOMES AND RESULTS: 92% of ASSQ high-scorers had a minimum of two other problems. Emotional problems, ADHD symptoms and learning problems were the most commonly reported problems, also predicting impairment and contact with services. CONCLUSIONS AND IMPLICATIONS: Co-occurring problems were common in ASD screen positive children and contributed strongly to both impairment and to contact with services. Gender differences indicated that female symptoms were perceived as less impairing by parents and teachers.