Deficits in agency in schizophrenia, and additional deficits in body image, body schema, and internal timing, in passivity symptoms.

Individuals with schizophrenia, particularly those with passivity symptoms, may not feel in control of their actions, believing them to be controlled by external agents. Cognitive operations that contribute to these symptoms may include abnormal processing in agency as well as body representations that deal with body schema and body image. However, these operations in schizophrenia are not fully understood, and the questions of general versus specific deficits in individuals with different symptom profiles remain unanswered.

The projected hand illusion: component structure in a community sample and association with demographics, cognition, and psychotic-like experiences.

The projected hand illusion (PHI) is a variant of the rubber hand illusion (RHI), and both are commonly used to study mechanisms of self-perception. A questionnaire was developed by Longo et al. (2008) to measure qualitative changes in the RHI.

Dexamphetamine effects on prepulse inhibition (PPI) and startle in healthy volunteers.

Rationale: Amphetamine challenge in rodent prepulse inhibition (PPI) studies has been used to model potential dopamine involvement in effects that may be relevant to schizophrenia, though similar studies in healthy humans have failed to report replicable or robust effects.

Objectives: The present study investigated dexamphetamine effects on PPI in healthy humans with an increased dose and a range of startling stimulus intensities to determine participants' sensitivity and range of responses to the stimuli.

Methods: A randomised, placebo-controlled dexamphetamine (0.