CLINICAL HANDBOOK OF SCHIZOPHRENIA

42. Intellectual Disability and Other Neuropsychiatric Populations 441• Psychosocial masking. This term refers to how experience affects the pathologicalmeaning of a symptom. For example, for an individual with moderate ID, a belief that heor she can drive a car might represent a grandiose delusion.• Cognitive disintegration. This term refers to a phenomenon in which limited copingskills result in significant behavioral decompensation or symptom emergence in responseto relatively minor stress. Such decompensation might not result in symptoms thatrise to the level of an Axis I diagnosis.• Baseline exaggeration. This term refers to a tendency to observe an increase in thefrequency and severity of chronic symptoms in association with a comorbid psychiatricdisorder. The diagnosis may be missed, unless one asks whether the frequency and intensityof these behaviors are new or long-standing.We consider several additional factors to be important.• Mixed and fluctuating symptom pictures. In our experience, some individuals havea mixed and fluctuating symptom picture that requires a longer observational time toclarify baseline primary behaviors, and their link to psychiatric and environmental triggers.• Mixed cognitive deficits. The presence of deficits in memory, attention, speech andlanguage, and executive functions can make obtaining an accurate history difficult.Placing events and symptoms in proper time sequence, or determining the consistencyand intensity of symptoms over time, may be a challenge. This issue highlights the importanceof involving family caregivers and other providers or knowledgeable individuals inobtaining a history. Problems in speech and language function can involve both propositionalcomponents (i.e., content, and prosodic components such as melody, amplitude,and voice pitch). Such speech and language deficits can make matching affect and contenta challenge. Depending also on the degree of intellectual impairment present, perseverativethinking or speech, or a limited repertoire of responses, can create problems of understanding.Persons with this problem may be limited to a few “play loops,” which theyrepeat over and over again, so that the examiner must learn to interpret the meaning ofsubtle changes in tone, pitch, and amplitude.• Filter effects of CNS injury. Many individuals with ID have other neurological deficitsin sensory or motor domains, or in other domains, through which the psychopathologymust be expressed, and by which the presentation will be variably altered. For example,consider how depression presents in someone who is nonverbal, how manichyperactivity presents in someone with quadriplegia, or how hallucinations and delusionspresent in someone with minimal speech and language function. As a general rule, themilder the cognitive impairment, the more classic the DSM-IV-TR symptom profile, aproposof a particular psychiatric diagnosis. The more severe the cognitive impairment, themore one must rely on the existence of putative risk factors for a given illness, such asschizophrenia, or on other indicators, such as disturbances in sleep, appetite, or overallactivity level.ASSESSMENT OF PSYCHOSIS IN PERSONS WITH IDWhen the question is whether a person with ID has a psychosis, circumspect clinical evaluationis essential. Careful assessment begins with obtaining as much historical information aspossible. This history includes family history, especially concerning any family memberswho have neurological or psychiatric illness. Obstetrical and perinatal histories are impor-