Clinical evidence suggests that three major patterns of disturbance of the supervisory mental processes that regulate self-generated mental activity can occur, either alone or together, in a variety of neurological and psychiatric conditions. Psychomotor poverty involves a diminished ability to initiate activity. Psychomotor disorganization reflects impaired ability to select between activities. Reality distortion, which is manifest as delusions and hallucinations, appears to reflect an abnormality of internal monitoring of mental activity. Each of these three syndromes is associated with a specific pattern of disordered function in multimodal association cortex and related subcortical nuclei. The evidence suggests that the neurotransmitter dopamine plays a major role in modulating the supervisory mental processes, though serotonin and noradrenaline are also implicated. While a particular neurotransmitter might have conflicting influences on different syndromes, the differential involvement of different anatomic sites and different neuroreceptor types offers the possibility of successful treatment even when different syndromes co-exist.