Increased semantic and repetition priming in schizophrenic patients

Positive and negative priming (PP and NP) in schizophrenia were studied with a lexical-decision task. Probe words, presented 800 ms after the response to the prime (containing a word and a nonword), were either identical to, semantically related to, or unrelated to the prime target word (PP) or to the prime distractor word (NP). Schizophrenic patients displayed stronger semantic and repetition PP than controls after controlling for their slower responses. Significant NP was observed in both groups for word repetition only. The PP findings contrast with results from studies with similar prime-probe intervals but without prime responses. It is proposed that schizophrenic patients, because of impaired (controlled) processes of response selection, strongly benefit from (or rely on) the automatic retrieval of processing episodes containing response information. Related findings indicating automatic response facilitation in schizophrenia are discussed.