Issues of measurement and mechanism in meta-analyses: comment on Westen and Morrison (2001).

The authors suggest that D. Westen and K. Morrison's (2001) meta-analysis of treatment is critically limited in the consideration of measurement and mechanisms of therapeutic change. The measures included in the analysis fail to represent a comprehensive coverage of the domains within which change is expected. Moreover, they do not measure the theoretically derived constructs currently conceived as being central to each disorder. Further, the particular meta-analytical approach taken prohibits evaluation of the treatment components responsible for change. The authors reviewed the most recent data on comorbidity as an issue of treatment efficacy and generalizability, proffer an interpretation for the difference in outcome results across the 3 diagnostic groups, and discuss internally valid methodologies for the bridging from research to clinical practice.

Cognitive theories of generalized anxiety disorder.

The hallmark feature of generalized anxiety disorder, worry, has been hypothesized to be a key factor in the production of threat-related information-processing biases in the domains of attention, memory, interpretation of ambiguity, and problem solving; however, worry and cognitive biases are not unique to generalized anxiety disorder. What may be unique to generalized anxiety disorder is the pervasive use of worry as a strategy to avoid intense negative effect and the broad domains in which these biases are exhibited, directly relating to the clinical observation that patients with generalized anxiety disorder worry about numerous life stressors. Also, the authors conclude that information-processing biases contribute to worry but that they are insufficient for the development of generalized anxiety disorder. Directions for future research and clinical implications are discussed.