Editorial: Thinking outside the box - enhancing causal models of neurodevelopmental disorders.

Neurodevelopmental disorders are best conceptualised as the result of multiple risk factors, which accumulate and determine the likelihood of reaching the threshold for fulfilling agreed diagnostic criteria. This multiple-risk framework allows the inclusion of research findings focusing on single disorders, while highlighting the need for extending and specifying existing causal models. Such specifications need to address at least three challenges: First, causal models need to account for the heterogeneity of symptoms within neurodevelopmental disorders, the dissociations between disorders, and also the high comorbidity rates observed between them. Second, causal models need to take into account the fact that associations between risk factors and psychopathology may be developmentally conditioned and are likely to change over time. Third, causal models need to incorporate a better understanding of the causal pathways between neurobiological risk factors and their interaction with environmental risk factors. Several articles in the present issue address these challenges, by assessing the interplay between neurobiological and environmental risk factors, and their impact on psychopathology, and by investigating how this relationship changes over time.