GineBlog

Los norteamericanos han triplicado el uso de antidepresivos entre 1988 y 2000, pero dos publicaciones en revistas de impacto científico ponen de manifiesto que la mayoría de pacientes sufrieron un efecto placebo. El tratamiento usado hace lo mismo que una pequeña dosis de azúcar.

Los investigadores, liderados por el profesor Irving Kirsch, han tenido que invocar la ley de libertad de información para analizar resultados sobre el inhibidor de la recaptación de la serotonina, como Prozac, la droga más usada para tratar problemas depresivos, y otras similares. El artículo publicado recientemente en el PLOS señala que 37 de los 38 estudios sobre antidepresivos con resultados positivos se publicaron, mientras que los que daban resultados negativos se publicaron 14 de los 36 estudios. Incluso entre los 14, muchos de ellos no resaltaban las ideas suicidas y desesperanza persistentes mientras que enfatizaban la mejoría del sueño y la sensación de energía. Los síntomas vegetativos (letargia, insomnio, poco apetito) de depresión en presencia de un humor depresivo continuado, juegan un papel significativo en el riesgo de consumar el suicidio.

El análisis de los estudios publicados y no-publicados de diferentes antidepresivos demuestran que el efecto de esos fármacos es el mismo que se consigue con una pequeña dosis de azúcar. Es simplemente un efecto placebo.

PLoS Med. 2008 Feb;5(2):e45.

Initial severity and antidepressant benefits: a meta-analysis of data submitted to the Food and Drug Administration. Kirsch I, Deacon BJ, Huedo-Medina TB, Scoboria A, Moore TJ, Johnson BT.

Department of Psychology, University of Hull, Hull, United Kingdom.

BACKGROUND: Meta-analyses of antidepressant medications have reported only modest benefits over placebo treatment, and when unpublished trial data are included, the benefit falls below accepted criteria for clinical significance. Yet, the efficacy of the antidepressants may also depend on the severity of initial depression scores. The purpose of this analysis is to establish the relation of baseline severity and antidepressant efficacy using a relevant dataset of published and unpublished clinical trials. METHODS AND FINDINGS: We obtained data on all clinical trials submitted to the US Food and Drug Administration (FDA) for the licensing of the four new-generation antidepressants for which full datasets were available. We then used meta-analytic techniques to assess linear and quadratic effects of initial severity on improvement scores for drug and placebo groups and on drug-placebo difference scores. Drug-placebo differences increased as a function of initial severity, rising from virtually no difference at moderate levels of initial depression to a relatively small difference for patients with very severe depression, reaching conventional criteria for clinical significance only for patients at the upper end of the very severely depressed category. Meta-regression analyses indicated that the relation of baseline severity and improvement was curvilinear in drug groups and showed a strong, negative linear component in placebo groups. CONCLUSIONS: Drug-placebo differences in antidepressant efficacy increase as a function of baseline severity, but are relatively small even for severely depressed patients. The relationship between initial severity and antidepressant efficacy is attributable to decreased responsiveness to placebo among very severely depressed patients, rather than to increased responsiveness to medication.