Background: The glutamate/ketamine model is gathering support as a useful adjunct to the dopamine hypothesis of schizophrenia (Javitt, 2007). One reason being that ketamine is capable of eliciting the cognitive deficits associated with this illness including those seen in semantic memory (Adler et al., 1998; Morgan et al., 2005). Two recent reviews (Rossell & Stefanovic, 2007; Pomerol-Clotet et al., 2008) have found larger than normal indirect semantic priming affects in schizophrenia suggesting an abnormality in implicit access to indirect relationships. In the current study, implicit and explicit tasks were employed to examine access to direct and indirect relationships in the semantic network. The purpose was firstly to see if the indirect priming findings from the schizophrenia literature can be replicated in a ketamine group (providing support for the ketamine model) and secondly, to determine whether such abnormalities are restricted to the indirect, implicit nature of the task or whether they are more wide spread and detectable in explicit and direct tasks. Should ketamine mimic schizophrenia deficits closely, then the answer to the second question will help to determine the nature of the semantic memory deficit in schizophrenia. Methods: This was a double blind placebo controlled cross over design. On one occasion, participants received ketamine, on the other, saline. On each occasion, participants completed a battery of semantic memory tasks along with measures of psychosis and dissociation. Results: The results showed statistically significant indirect priming under the influence of ketamine but no significant indirect priming in the same individuals in the placebo condition. In addition, ketamine only disrupted semantic access significantly on indirect tasks. Discussion: Priming effects under ketamine matched those seen in schizophrenia offering support for the ketamine model. Further, semantic memory deficits were found to be associated with indirect relationships regardless of the implicit/explicit nature of the task.