Children and adults with developmental disabilities are at increased risk for experiencing behavioral problems and psychiatric comorbidities compared to the general population and several neurodevelopmental disorders are associated with certain neuropsychiatric conditions. Because of language and cognitive differences, the clinical presentation of these conditions can differ from what is seen in the general population. Furthermore, research on treatment approaches for psychiatric comorbidities in these populations is extremely limited and evidence-based treatment guidelines do not exist.  This book is a collection of neurodevelopmental disorders that are frequently associated with relatively distinct and common psychiatric co-morbidities across the lifespan. Each chapter addresses a different neurodevelopmental disorder by providing an overview, symptoms of common psychiatric co-morbidities, assessment strategies, psychosocial and biological treatments, and common medical co-morbidities the clinician needs to have basic knowledge of with regards to choosing safe and appropriate pharmacotherapy. Given how relatively rare many of these syndromes are, the practicing clinician generally does not encounter a sufficient number of cases during training or clinical practice to develop comfort and expertise in each of them. Furthermore, there are no easy to access evidence-based treatment guidelines. This succinct and practical resource fills a needed gap for an overview of the most common neurodevelopmental disorders in a single resource with a clinical expert’s approach to diagnosis and management.