Abstract
BACKGROUND: Adults with intellectual disability experience increased rates of mental health disorders and adverse mental health outcomes. AIM: Explore childhood risk factors associated with adverse mental health outcomes during adulthood as defined by high cost of care, use of psychotropic medication without a severe mental illness and psychiatric hospital admissions. METHOD: Data on 137 adults with intellectual disability were collected through an intellectual disability community service in an inner London borough. Childhood modifiable and non-modifiable risk factors were extracted from records to map onto variables identified as potential risk factors. Logistic and linear regression models were employed to analyse their associations with adverse outcomes. RESULTS: We showed that the co-occurrence of intellectual disability with autism spectrum disorder and/or attention-deficit hyperactivity disorder (ADHD) were associated with psychotropic medication use and high-cost care packages. However, when challenging behaviour during childhood was added, ADHD and autism spectrum disorder were no longer significant and challenging behaviour better explained medication prescribing and higher cost care. In addition, the severity of intellectual disability was associated with higher cost care packages. Ethnicity (Black and mixed) also predicted higher cost of care. CONCLUSIONS: Challenging behaviour during childhood emerged as a critical variable affecting outcomes in young adulthood and mediated the association between adult adverse mental health outcomes and co-occurring neurodevelopmental conditions, that is, ADHD and autism. These findings emphasise the need for effective early intervention strategies to address challenging behaviour during childhood. Such interventions for challenging behaviour will need to take into consideration autism and ADHD.