Review of the Use of Pattern Analysis to Differentiate True Drug and Placebo Responses

Abstract

Placebo response in patients assigned active drug is a troubling source of variance in antidepressant studies. This paper summarizes a series of studies utilizing pattern analysis to distinguish between placebo and true drug responses. Analysis of the persistence, speed, and timing of onset of patients’ improvement during antidepressant therapy reveals distinct patterns of response which are likely to be attributable to placebo and true drug effects. While true drug effects seem to be characterized by a 2-week delay in onset followed by persistent improvement, placebo effects seem to be characterized by abrupt, transient improvement. Gradual responses on placebo may be due to spontaneous remission. The heuristic and clinical implications of pattern analysis are discussed.

Curcumin for the treatment of major depression: A randomised, double-blind, placebo controlled study

“…From a statistical point of view, when performing the analyses on the whole treatment period, the positive placebo response in the first month of treatment masked the positive gains from curcumin over the second study period (weeks 4 to 8). Placebo responses in depression trials are common and it has been suggested that true drug responses are characterised by a 2-week delay, with continued improvement thereafter, whereas placebo effects are characterised by abrupt, transient improvements (Rothschild and Quitkin, 1992). Although assessments were not completed until week 4, this study confirms a similar pattern of change -that is, in placebo-treated individuals, a response in the first month, followed by no change, or even worsening of symptoms thereafter.…”

DSM-IV Diagnoses and Obstructive Sleep Apnea in Children Before and 1 Year After Adenotonsillectomy

“…Changes of this large magnitude, reported by parents and confirmed by psychiatrists a year after the procedure, are not likely to represent expectancy effects alone. "Placebo" effects, in contrast, typically occur earlier in treatment and are far less durable than the outcomes presented here (Rothschild and Quitkin, 1992). Similarly, psychiatric ratings showed robust correlations with parent ratings and modest (as expected) correlations with objective measures of attention and impulsivity.…”

Do Antidepressanf and Antianxiety Drugs Increase Chronicity in Affective Disorders?

“…The loss o f antidepressant effects during continuation therapy has been attributed to drug tolerance [15], since it responded to an increase in dosage [14,15]. Even though a cer tain percentage o f relapses might be due to the loss o f nonspecific placebo effects [ 16] rather than to true drug effects, this clinical phenom enon is intriguing. Equally intriguing are the results of a naturalistic prospective survey, where low doses o f antidepressants appeared to be less beneficial than either higher doses or clinical management without antidepressant drugs [17], The latter two treatments yielded almost identical outcome.…”