The Schizophrenia Spectrum Personality Disorders

Early phenomenological descriptions of schizophrenia have recognized the existence of conditions characterized by the presence of attenuated forms of the symptoms normally present in this disorder. The examination of these schizophrenia spectrum disorders might elucidate the pathophysiological mechanisms giving rise to schizophrenia. Differences and similarities between subjects with schizotypal personality disorder (SPD), the prototypic schizophrenia personality disorder, and schizophrenia are being examined with genetic, neurochemical, imaging, and pharmacological instruments. Patients with SPD and those more severely ill with chronic schizophrenia share cognitive, social, and attentional deficits hypothesized to result from common neurodevelopmentally-based cortical temporal and prefrontal pathology. However, these deficits are milder in patients with SPD due to their capacity to recruit other related regions to compensate for dysfunctional areas. Also, these individuals are less vulnerable to psychosis due to the presence of protective factors against subcortical dopamine hyperactivity. Their decreased vulnerability to psychotic exacerbations and their more readily cognitive and social deficit improvement after the use of cognitive enhancement agents, result in subjects with SPD constituting an ideal population to employ in pharmacological cognitive enhancement studies of the schizophrenia spectrum.