Estimation of placebo Effect in Therapy of Generalized Anxiety Disorder

Abstract

Studying of placebo response in patients with Generalized Anxiety Disorder (GAD) was the aim of research. 90 patients (68 female, 22 male, mean age of 33 years) were studied. All patients accepted inactive placebo (P) within 7 days and then - Alprazolam (A) in a dose of 1-3 mg per day within 4 weeks. Efficacy of treatment was estimated weekly by the HAM-A scale. After week of placebo reception, patients with HAM-A score < 9 made group of remission (R), with ≥50% HAM-A reduction - placebo responders group (PR), with HAM-A reduction 25-49% - partial placebo responders group (PPR), ≤ 25% HAM-A reduction - placebo nonresponders group (PNR).After week of reception placebo 16.6% of patients HAM-A made group R, 26.7% - PR; 30% - PPR, 26.7% - PNR. After active therapy (A) Therapeutic Remission group (RT - HAM-A score < 9) consisted of 100% of group R, 75% of PR, 81.5% of PPR and 8,33% of PNR. 25% of PR, 18% of PPR and 8.33% of PNR became Therapeutic Responders (TR - HAM-A reduction >50%). Partial Therapeutic Responders (PTR - HAM-A reduction 25-49%) and Therapeutic Nonresponders (TNR ≤ 25% HAM-A reduction) consisted only of PNR (62.5% and 20.83%).Absent response on (P) frequently correlated with low efficacy of therapy of (A). High positive placebo effect (PE) was defined in patients in whom improvement after transferring on active therapy became even more expressed. The received data allow to consider presumably PE like predictor of efficacy of benzodiazepines therapy for GAD.

Efficacy of Silexan in patients with anxiety disorders: a meta-analysis of randomized, placebo-controlled trials

“…In anxiety disorders, an appreciable proportion of patients has been shown to respond favorably to placebo treatment [ 25 ]. This is also a known issue in placebo-controlled trials in the indication, and placebo response rates have been shown to even rise during the last decades [ 51 ].…”