The phenomenon of high placebo response can be a “formidable challenge in clinical trials but a largely untapped resource in clinical practice,” authors Jeffrey R. Strawn, M.D., and colleagues write in a chapter in a new book from APA Publishing on prescribing mental health medication to youth.¹ They argue the expectations of the effectiveness of treatments play a key role in the outcomes of mental health care for youth.

Placebo response refers to the improvement that patients perceive or experience in response to inactive therapeutic agents. Placebo response occurs commonly in clinical mental health research for adults and children.

Placebo response is “one of the most significant barriers to detecting treatment effects in both pediatric and adult clinical trials,” the authors write. “At the same time, the value of placebo response to improvement in the clinic is undeniable.” Strawn and colleagues review what is known about the impact of the placebo effect in clinical research and in practice. They suggest that individual factors are often overlooked in examining placebo effect: "Patients vary how much they expect treatment to work and how much they believe that they can improve, and these are powerful drivers of clinical response.”

The authors examine some of the factors that influence the placebo effect its impact in different circumstances, especially in studies of adolescents with depression and anxiety. For example, in studies with children and adolescents, placebo response is lowest in patients with obsessive-compulsive disorder (OCD), followed by anxiety disorders, and is greatest in those with major depressive disorder. Placebo response often occurs early and plateaus. In studies of youth with anxiety, the effect tended to decrease after four to eight weeks; but in studies of those with depression, the effect did not decrease. Children and youth with less severe depression have been found to have greater placebo-related improvement than those with more severe depression. Among those with depression, younger children tend to have greater placebo responses than adolescents.

Among youth with anxiety, those that have greater expectations of the benefits of treatment may be more likely to participate in and stick with treatment, which in turn can lead to better outcomes. In addition, the authors note, having positive expectations of treatment in and of itself may decrease anxiety.

Strawn and colleagues also describe a phenomenon of placebo by proxy, which refers to placebo improvement related to the child’s or youth’s interaction with parents and family members who are feeling better because the child/youth is receiving treatment. The caregiver, the authors explain, experiences reduced distress and increased support from the treatment, and this may change their behavior toward the child, which can facilitate the child’s improvement.

The authors suggest mental health professionals should actively explore their patients’ expectations for the success of a given treatment, work to increase their expectations for success, and address patients’ intolerance of uncertainty and negative expectations.