All ages have a strong placebo effect in trials for anti-anxiety therapies

The strong placebo effect seen in randomized clinical trials involving treatment for anxiety disorders is consistent across all age groups studied, according to a new analysis. Researchers from Brazil, the Netherlands and the U.S. conducted a meta-analysis of 135 trials of selective serotonin reuptake inhibitors (SSRIs) and serotonin and norepinephrine reuptake inhibitors (SNRIs) for patients with anxiety, obsessive-compulsive disorder and stress disorders. Past research indicates that the placebo response differs across the lifespan in other mental health disorders, including depression. This suggests that trials finding a lower effect of the treatment in pediatric patients may be due to a higher placebo response and not less of a reaction to the active agent. In this meta-analysis, the researchers wanted to know if the placebo effect differed in various ages. They found that placebo response was similar and remained strong in trials involving children and adolescents, adults and the elderly with anxiety disorders, although generalized anxiety disorder was the only condition assessed in each age group. The average response rate in placebo groups was 37% and the average remission rate in placebo groups was 24%. Placebo groups had higher response rates if they included people with generalized anxiety disorder or PTSD than if they included people with panic, social anxiety or obsessive-compulsive disorder. Read: Screen time is contributing to chronic sleep deprivation in tweens and teens The results mean that clinicians should take the placebo effect into account when comparing the efficacy of different SSRI and SNRI treatments for different mental health disorders, said Dr. Natan Pereira Gosmann, corresponding author of the paper and a researcher at Universidade Federal do Rio Grande do Sul in Porto Alegre in Brazil. Physicians should also note how the effect was measured. The researchers found that there was a difference in response when patients self-reported outcomes compared to when physicians scored outcomes, particularly on patients with generalized anxiety disorder. In the clinic, physicians wanting to properly evaluate the benefit of the medications should include input from both patients and assessment tools, Dr. Pereira Gosmann said. Previous studies suggest that patients with anxiety disorders also have a higher number of adverse events due to the ‘nocebo’ effect, when patients have negative expectations of treatment. A person’s diagnosis affects the placebo or nocebo effect. People with anxiety disorders may have unrealistic expectations or catastrophic beliefs about the treatment, Dr. Pereira Gosmann told the Medical Post. Physicians need to take the time to counsel the patients about the treatments. “Given the interaction between patient and clinician significantly influences the likelihood of these effects, the exploration of patients’ expectations, and the realistic and precise description of potential benefits and harmful events in a positive way, may substantially contribute to successful treatments,” Dr. Pereira Gosmann said. The study was published in BMJ Mental Health. Read: When patients see medication as an ‘admission of failure’

All ages have a strong placebo effect in trials for anti-anxiety therapies

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