The role of anxiety in the development of anticipatory nausea in cancer chemotherapy: a review and synthesis.

The role of state anxiety in the development of anticipatory nausea and vomiting (ANV) in cancer chemotherapy has been the focus of considerable empirical investigation and theoretical speculation. However, while some relationship between state anxiety and ANV is presumed to exist, determination of its precise nature has proven elusive. Specific hypotheses linking state anxiety to ANV are described and evaluated in light of the empirical evidence. These hypotheses include (a) ANV is a symptomatic concomitant of state anxiety; (b) state anxiety directly facilitates the classical conditioning of ANV; (c) state anxiety exacerbates the magnitude of post-treatment nausea and vomiting experienced, thus increasing the risk of ANV; (d) ANV causes infusion-related state anxiety; and (e) the observed relationship between ANV and state anxiety is a result of methodological artifact. It is concluded that state anxiety can play a causal role in the development of ANV in some patients. In particular, the hypothesis that state anxiety exacerbates post-treatment nausea and vomiting and thus increases the risk for ANV appears best supported by the data. Finally, the clinical implications of the relationship between ANV and state anxiety for the treatment and prevention of ANV are discussed.