d metabolic disorders, neurophysiological and neuroimaging studies. These data need to be formulated for each phase of this outline for differential diagnosis. Clinical screening and neuropsychological testing are useful when dementia is suspected (35, 36).
Integrate medical/psychiatric assessment with functional behavioral analysis: Missing from many functional behavioral analyses are information about temperament, level of emotional reactivity, neuroticism, patterns of attachment, preponderance of approach/avoidance behaviors, emotional regulation, and level of impulse control. These neurobiological traits can profoundly influence a patient’s vulnerability to specific antecedents or triggers (8). For example, individuals with a history of severe abuse may be hypersensitive to being left alone at night, or attempts to set limits (18, 37, 38). This data may help explain what appears to be a persistent, disproportionate and treatment resistant reaction. A similar expanded mode of analysis involves both motivational and sustaining factors. For example, state-related anhedonia in major depression can reduce the reinforcement efficacy of social contact or favored activity (39). Likewise negative emotional reactions to novel situations or new staff or fear noted above should determine the pace of changes in behavioral programming (35, 37, 40, 41).
Social context of behaviors: Aggression (42), self-injury and other target behaviors occur in a social context. For many patients with SPIDD, aggression or SIB can represent forms of social communication (43) or expressions of attachment, dominance and territorial disputes (e.g. whose chair is this?). Psychiatric disorders also occur within and affect social networks, families, school and in work settings. Formulating this data may be more useful than a simple Axis V number in treatment planning (8, 44).
The last step is developing a multiaxial, psychiatric diagnosis. In the past there was difficulty matching the patient to the diagnostic criteria that were not adapted to the special issues associated with IDD. Fortunately the Diagnostic Manual-Intellectual Disability and Diagnostic Criteria-Learning Disability are now available to assist clinicians in negotiating a clinical diagnosis.
The diagnosis and treatment of mental disorders in adults with IDD requires that the clinician is able to negotiate two worlds. As a team member, the psychiatrist often plays the role of translator between the world of the neurosciences and biomedicine and the team. As we have seen, the differential diagnosis can present some of our greatest challenges. For example, schizophrenia is frequently diagnosed and treated based on the presence of hallucinations or delusions without a comprehensive exploration of psychosis; psychotic forms of major depressive, bipolar disorder, PTSD, delirium, dissociative states and intoxication can occur (3). A parallel problem arises when clinicians prescribe psychopharmacological treatment for aggression, self-injury, agitation and disruptive/destructive behaviors without thorough reviews of environmental factors (social ecology), review of neurobiological setting events and functional behavioral analyses. In either of these scenarios the rush to treat can result in the long-term exposure but often ineffective treatment regimens that all too often result in unnecessary polypharmacy (30, 44).
Traditionally, most mental health clinicians accept the view that mental disorders arise from the interaction between psychosocial stresses and biological/genetic risks for a particular mental disorder (“two hit theories”). Some colleagues take a different approach, viewing challenging behaviors as learned phenomena. These behavioral specialists tend to focus less on accurate diagnosis and biogenetic etiology (8). Yet in light of our current knowledge, neither approach provides the ultimate solution. As clinicians we need to consider both challenging behaviors and mental disorders as lying on a continuum. From this perspective, challenging behaviors are attributed to environmental str