Can pregnancy be a placebo effect?: Terminology, designs, and conclusions in the study of psychosocial and pharmacological treatments of behavior disorders.

This paper discusses several salient issues in the clinical research enterprise which were stimulated by chapters on research methods and placebo phenomena in White, Tursky and Schwartz (1985), Placebo: Theory, Research, and Mechanisms. These issues include the commonalities of questions, domains and classes of variables, and research strategies needed for the discovery, accumulation and application of knowledge regarding effective clinical treatments. Problems of unwarranted uniformity assumptions and absolute design requirements as well as the failure to attend to the conceptual relevance, strength and integrity of procedures are noted with examples from the systematic desensitization literature. Meta-analyses and indexes of effect size are also examined with examples demonstrating the need for especially cautious interpretation of these procedures. A re-emphasis of the construct validity approach with better designed and executed individual studies is endorsed as the best means to improve progress.