Descriptive Psychopathology: The Signs and Symptoms of ...

57 Chapter 3: The brain and psychopathologyUnderstanding established brain–behavior relationships strengthens the recognitionof psychiatric illness when the pattern of psychopathology is ambiguous(e.g. avolitional frontal syndrome versus depressive illness; disinhibited frontalsyndrome versus mania). The understanding helps identify neurologic diseasewhen the disease’s expression is mostly as psychopathology (e.g. psychosis due tostrokes outside the motor system, many persons with partial complex seizures). Forexample, MacDonald Critchley’s monograph (1953) on the parietal lobes describespatients hospitalized with recognized strokes in their right (non-dominant) parietallobe. Many of these patients also exhibited classic psychopathology.A woman said:“I had a terrible shock this morning when I touched my left hand; I thought it was the head of areptile.” Asked where her left arm was, she said, “I don’t know. Where is it? I don’t feel it.” Whenconfronted with her left hand, she said, “That is someone else’s hand.” Whose is it? “It is not mine.”This patient exhibited a passivity delusion, experience of alienation, which wasonce thought pathognomonic of schizophrenia. 20 Her non-recognition of herhand and her illness is anosagnosia, or denial of illness. 21 From Critchley’sdescription of her lesion it can be surmised that a slightly smaller lesion couldhave produced similar psychopathology without other stroke features. Such apatient coming to a busy emergency room today would likely be diagnosed ashaving psychosis (NOS) and an antipsychotic needlessly prescribed.Another patient is described with the Cotard syndrome or delusion of nihilism. 22In an effort to recapture the feeling of her body which she believed she had lost, [the] patientran naked into the grounds and flung herself into the snow. A similar “disappearance” or“rotting away” of the body has been encountered after focal cerebrovascular lesions.Classic “psychological” symptoms also reflect disturbed brain function. La belleindifference, a patient’s apparent lack of concern for severe symptoms, is observedin some persons diagnosed as having conversion disorder. But conversion disordersare also understood as subtle forms of neglect from right hemispheredysfunction. Functional imaging techniques reveal brain abnormalities in suchpatients. 23 In studies of unilateral motor “conversion” contralateral frontal andthalamic hypometabolism is consistently reported. 24 This is the opposite of whatoccurs in voluntary movement and in subjects feigning paralysis. 25Functional brain systems and psychopathologyBrain functional organization guides understanding of brain–behavior relationships.The brain consists of several functional systems differentially affected bydisease (e.g. herpes encephalitis often involves the temporal lobes). The systems