(The following work has been been published as a chapter in the book "Intervening Early in Psychosis: A Team Approach", edited by Drs. Hardy, Ballon, Noorsdy, and Adelsheim).
Most psychotic disorders, including schizophrenia spectrum disorders, begin with a prodromal period characterized by attenuated positive and negative symptoms as well as altered functioning before the onset of a full psychotic episode. These sub-threshold symptoms differ from symptoms associated with full psychotic episodes in their intensity, frequency, and/or duration. Nevertheless, these symptoms, in combination with additional risk factors, may increase the likelihood of developing a psychotic disorder and may predict clinical severity and general functional outcome. For example, deficits in neurocognition (e.g., memory, attention, executive functioning, perceptual processes) appear during the prodromal stage and remain present throughout illness progression and may represent a core feature of psychosis-related disorders. Furthermore, cognitive impairments remain after psychopharamacological intervention and symptomatic stabilization and have been shown to be a main predictor of functional outcome in patients with early and chronic psychosis. Additionally, negative clinical symptoms such as anhedonia, blunted affect, avolition, and apathy occur during the high-risk period and remain persistent throughout the course of illness, and these symptoms typically respond poorly to psychopharamacological intervention. These clinical and affective impairments negatively influence patients' disability levels and ability to function in all areas of daily life, including social and occupational areas, and do not appear to be treatable using traditional antipsychotic medications.
Although psychopharamacological intervention is widely used in psychotic disorders and may treat specific symptoms (such as hallucinations or other positive symptoms), very few, if any, interventions exist that reliably improve neurocognition and functioning in this population. Therefore, it is imperative to develop intervention strategies that target neurocognitive deficits in people experiencing psychosis, which may subsequently improve general functional outcome. One recent intervention that targets these factors for both chronic and early psychosis patients includes using the benefits of increased physical activity or exercise. Exercise refers to structured, planned, and repetitive physical movement to maintain or improve one or more mechanisms of physical fitness. In this chapter, we detail the potential benefits of physical activity, primarily aerobic exercise interventions, for cognitive and negative symptoms in people with psychotic disorders.