Confident memory errors and disrupted reality testing in early psychosis

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Schizophrenia is a psychiatric disorder characterized by a disruption in reality testing most often manifest in the form of delusions and hallucinations. Because determining the reality-basis of prior experiences is dependent on episodic and associative memory, deficits in mnemonic processes could be involved in the genesis of impaired reality testing. In the present study, we used an associative memory paradigm incorporating confidence ratings to examine whether patients with a recent onset of schizophrenia (n = 48) show a greater propensity for confident, yet incorrect responses during retrieval testing than healthy controls (n = 26) and whether such confident incorrect responses, specifically, are more strongly associated with positive symptoms than with negative symptoms. Using an analysis of variance design, we found that first-episode schizophrenia patients made a significantly greater number of confident errors than controls (i.e. they expressed high confidence in having seen pairs of items that were not paired at encoding and high confidence in having not seen pairs of items that were paired at encoding). We also found that the number of confident errors was specifically and differentially associated with positive symptom severity, to a significantly greater degree than with negative symptom severity and psychosocial functioning, and this association was not found between positive symptoms and uncertain responses, nor positive symptoms and overall task performance. These findings suggest that the propensity for incorrect memory judgements with high confidence, specifically, may be uniquely associated with disrupted reality testing and that this type of cognitive impairment is distinct from general deficits in memory and cognition in this respect.