Background. Schizophrenia patients, particularly those with symptoms such as thought insertion,
passivity experiences and hallucinations, may share an underlying cognitive deficit in monitoring the
generation of their own thoughts. This deficit, which has been referred to as ‘autonoetic agnosia’,
may result in the conclusion that self-generated thoughts come from an external source. Previous
work supports this notion, yet the statistical approaches that have been used have not enabled a
distinction between specific deficits suggesting autonoetic agnosia and more general cognitive
Methods. Autonoetic agnosia was assessed using source-monitoring paradigms in 28 patients with
schizophrenia and 19 control subjects. Multinomial model analyses, which allow the distinction
between deficits in recognizing information, remembering its source, and response biases, were
applied to the data.
Results. Schizophrenia patients were impaired in discriminating between words that came from two
external sources, from two internal sources, and one internal and one external source. In a condition
requiring subjects to distinguish between words they had heard from those they had imagined
hearing, when schizophrenic patients did not remember the source of the information, they showed
a stronger bias than controls to report that it had come from an external source.
Conclusions. The application of multinomial models to source monitoring data suggests that
schizophrenia patients have source monitoring deficits that are not limited to the distinction
between internally-generated and externally-perceived information. However, when schizophrenia
patients do not remember the source of information, they may be more likely than controls to report
that it came from an external source.