A cognitive neuropsychiatric analysis of psychomotor symptoms in major depression and schizophrenia

A cognitive neuropsychiatric analysis will be proposed by presenting recent research on -1-motor control, and -2-action monitoring in two psychiatric disorders i.e. major depression and schizophrenia. Motor control is best studied from the broader cognitive neuropsychological perspective of action control. Even very simple actions implicate quite diverse brain activities reflecting the cognitive processes of planning, selection, visuomotor integration, timing, force adjustment, and action monitoring. The extent to which deficits in these cognitive processes cause slowed or stereotypic actions can be experimentally studied in clinical settings by means of graphic tasks, as will be illustrated. A central process in motor/action control is error monitoring. The last decade research on this higher cognitive control process has been booming, also because the detection of errors is accompanied by a clear peak in the EEG, known as the error-related negativity (ERN). Deficient error monitoring has been observed in several psychiatric disorders. ERN studies in major depression and schizophrenia will be discussed. Psychiatric disorders can best be understood by considering three perspectives, i.e. psychopathology, cognitive neuropsychology and neuroscience. The findings support the view that cognitive neuropsychiatry should involve the combined study of psychiatric symptoms, cognitive dimensions and neurological structures.