Cognitive and psychopathological change in degenerative disease in the elderly

Neuropsychological studies of declining cognitive ability and increasing psychopathology in degenerative neurological diseases in the elderly suggest the following: (1) the physiological basis for affective and thought disorder remains elusive; (2) cognitive capacity and primary psychopathology are not clearly related in degenerative disease; rather neuropsychological studies in this area illustrate a dissociation between accessory (secondary) symptoms of psychopathology and cognitive changes; (3) accessory symptoms of thought disorder may be associated with disorders of the basal ganglia; and (4) current nosology of affective and thought disorders is probably not appropriate when dealing with onset of psychopathology in the elderly. There is a need to closely attend to logical inference in neuropsychological data from this group of patients, and to clearly differentiate primary from secondary symptoms of affective and thought disorders.