Conceptual implicit memory in subclinical depression

Depression adversely affects explicit memory when implicit memory remains intact unless implicit retrieval requires conceptual processes. The impairment of conceptual implicit memory could be the consequence of the completion of implicit memory tests being contaminated by a voluntary retrieval strategy, hence similar results to those in explicit tests are observed. In this study we adopted a method sensitive to the presence of contamination. Depth-of-study-processing effects were observed for the controls completing the explicit version of a word-association task but were absent for the controls completing the implicit version when compound associates were retrieved. This dissociation indicated the adoption of the designated retrieval strategy in each test with the conceptual implicit memory test being uncontaminated. Subclinically depressed participants showed impairment in the explicit version, while for those completing the implicit version there was evidence that they used a voluntary retrieval strategy. The theoretical implications of the findings are discussed.