Aggressive behavior is a common referral problem for individuals with developmental disabilities (DD), placing them at risk for institutionalization, social isolation, physical restraint, over-use of medication to treat behavior problems, exclusion from services, and becoming a victim of abuse. Aggression strains relationships between individuals being supported and their caregivers, whether professionals or family members. The treatment of aggression is persons with DD, with or without comorbid mental illness, remains a controversial area and changes in practice have been slow to come. The evidence related to pharmacotherapy and psychological treatment is, in general, either lacking or poor. This does not suggest that these treatments are necessarily ineffective but that there is not enough good quality evidence to support their usefulness. This review considers the prevalence and correlates of aggression, as well as possible causative factors. The relationship between mental illness, intellectual disability and aggression is explored. The psychopharmacological and psychological treatment literature is reviewed with implications for clinical care and future research.

Anxiety disorders are common in individuals with developmental disabilities (DDs), although they may not be diagnosed and treated as often as they are in patients without DDs. Patients with mental retardation, autism, and other pervasive developmental disorders may exhibit comorbid anxiety disorders, such as generalized anxiety disorder (GAD), obsessive-compulsive disorder (OCD), phobias, and other anxiety symptoms at much higher rates than in the general population, but identification of these comorbid anxiety disorders may be made more difficult by the presence of the DD and concurrent difficulties with communication, other behavior problems, the lack of standardized assessments specific to diagnosing patients with DDs and psychiatric comorbidities, and the need for greater collateral sources of assessment information. In addition, systematic study of the treatment of anxiety in patients with DD is limited to a relatively small number of empirical studies done specifically in these patients along with case reports and theoretical reviews on the extension and modification of more well-studied treatments used for anxiety in patients without DDs. The present article reviews the literature on the prevalence, features, assessment and diagnosis of anxiety disorders in individuals with DDs, and also reviews empirical studies of pharmacological and psychological treatment of patients with comorbid anxiety and DD and summarizes the findings. Recommendations are made to guide treatment and further research in this area.

The presence of co-occurring psychiatric disorders among individuals with developmental disability (DD) requires clinicians to adjust and modify standard mental health assessment and treatment planning. In particular, assessment includes input from a multi-disciplinary team and as a result, diagnosis is frequently a synthesis of data from many different points of view. Treatment planning and implementation commonly include a collection of highly specialized, individualized programs that focus on the long term management of both disorders. Crises and recurrence of mental disorders are commonplace in part due to the presence of ongoing risk and vulnerability factors for mental disorders. As a result, the need for emergency interventions, specialized respite services, hospitalization and other transition services is extensive. The quality, availability and access to these services vary considerably. Many programs are concentrated in metropolitan or university-based centers and pose hardships based on geographic distance. The availability and utilization of services is affected by political, economic, socio-cultural and psychological forces that impact both the willingness to use services and the distribution of professionals trained and qualified to manage individuals with dual diagnoses. The complex interaction between each of these factors determines the structure, function, and capacity for innovation built into current service models.