Rebuttal: The black swan fallacy in evaluating psychological interventions for distress in cancer patients

Isolated clinical trials in which psychosocial interventions to reduce distress among cancer patients appear superior to control conditions are insufficient to establish the overall efficacy of this class of interventions. We note that Andrykowski and Manne (1) depend on reviews that include nonrandomized trials in their case for the efficacy of these interventions and the one exception is a review that provides a pessimistic assessment of their efficacy. Four of the five intervention trials Manne and Andrykowski (2) cite as the best available evidence failed to provide the requisite treatment by time interaction needed to demonstrate efficacy. Even this best foot forward set of arguments fails to provide even a modest case for the efficacy of psychosocial interventions to reduce distress among typical cancer patients. We note the need to consider more carefully possible adverse effects and other costs of these interventions.