Semantic priming in remitted patients with bipolar disorder

Background and objectives Semantic priming disturbances are increasingly recognized as a feature of schizophrenia, and increased priming has been suggested to constitute a “cognitive correlate” of positive formal thought disorder (FTD). The present study aimed to investigate semantic priming in patients with bipolar disorder (BD). Methods A primed lexical decision task with strongly related (STR), weakly related (WR), or unrelated (UR) prime-target pairs (SOA = 250 ms) was administered to fourteen remitted patients with BD and twelve control subjects matched on key demographic variables. FTD was measured by means of the Scale for Thought, Language and Communication (TLC). Results Control subjects showed a robust (59.6 ms) and statistically significant priming effect for STR words, while priming for UR words was non-significant. In patients there was no evidence of priming in either condition. In patients, there were no significant correlations between priming magnitude and TLC scores. However, the only patient with a positive score on the TLC disorganization factor exhibited evidence of hyperpriming. Limitations The present patient sample exhibited very low TLC scores, and no direct comparison to patients with schizophrenia was possible. Conclusions The finding of decreased priming in patients with BD raises the possibility that semantic processing abnormalities in BD are of a different nature than those encountered in schizophrenia. Due to the small size and very low TLC scores of the present patient sample, no definite conclusions can be drawn as to the relationship of formal thought disorder and semantic processing abnormalities in BD.