Study: Patient Expectations Influence Effectiveness of SSRI Antidepressants

Presentation of the treatment may be as important as the treatment itself

Selective serotonin reuptake inhibitors (SSRIs) are commonly prescribed for depression and anxiety but their superiority over placebo has been questioned, generating considerable debate among researchers and clinicians. In a new study, Uppsala University researchers show that the way in which the treatment is described to the patient can be as important as the treatment itself.

In the debate among clinics and researchers on SSRIs, it has been argued that SSRIs may lack specific therapeutic properties and that their beneficial effects, observed in clinical trials, could be explained by different expectancies in the drug and placebo groups. In a double-blind study, the participant may come to realize that he or she has been given the drug instead of the placebo because of the side effects he or she experiences; this may in turn result in increased expectations of improvement and reporting of a better effect. However, as of yet, just how much the clinical effect of SSRIs can be influenced by the patient’s expectancies (induced by the information patients receive at prescription) has not been tested experimentally.

In a study published in EBioMedicine, researchers at Uppsala University’s Department of Psychology in Sweden demonstrate considerably better effects of the SSRI escitalopram when it is given with correct information compared with incorrect verbal information.

In the randomized study, all patients with social anxiety disorder were treated with the same dosage of escitalopram for nine weeks, but only one group was correctly informed about the drug and its effectiveness. By use of a cover story, the other group was led to believe they were being treated with a so-called “active placebo,” yielding similar side effects as the SSRI but out of which no clinical improvement could be expected.

“Our results show that the number of responders was three times higher when correct information was given than when patients thought they were treated with an ineffective active placebo, even though the pharmacological treatment was identical,” says author Vanda Faria.

Moreover, assessments with magnetic resonance neuroimaging showed that the SSRI had different effects on brain activity when associated with expectations of improvement. There were differences between the two groups in activations of the posterior cingulate cortex and the coupling between this region and the amygdala, which is central to fear and anxiety.

“This may reflect an interaction between cognition and emotion as the brain changes differently with medication pending on the patient’s expectancies,” says coauthor Malin Gingnell.

The results imply a marked placebo component related to expectancies in SSRI treatment, underscoring the importance of the communication between prescriber and patient.

“We don’t think SSRIs are ineffective or lack therapeutic properties for anxiety, but our results suggest that the presentation of the treatment may be as important as the treatment itself,” says Professor Tomas Furmark, who led the study.

Source: Uppsala University; October 3, 2017.