Background. A number of studies have suggested that indirect semantic priming is enhanced in
thought-disordered schizophrenics. However, research on direct semantic priming has produced
conflicting results. The aim of the present study was to resolve some of the ambiguities of previous
Methods. For the present study, 44 schizophrenic patients were split according to the presence of
associative loosening into a positive thought-disordered (TD) and non-positive thought-disordered
(NTD) group. Thirty healthy subjects and 36 psychiatric patients served as controls.
Results. Schizophrenics displayed increased indirect semantic priming compared with psychiatric
controls. When subtyping the sample, TD-patients exhibited significantly enhanced indirect
semantic priming compared with healthy and psychiatric controls as well as NTD-patients. Overall
slowing was found to be independent of priming effects. Medication, age and chronicity of the
schizophrenic illness did not modulate priming.
Conclusions. In line with Spitzer and Maher it is inferred that disinhibited semantic networks
underlie formal thought disorder in schizophrenia. For future research, it would be appropriate to:
employ indirect semantic priming rather than direct semantic priming conditions; and, pay more
attention to potential moderators of the priming effect, most importantly, the prime display
duration and the length of the stimulus onset asynchrony.