Not necessarily, but “clown doctors” and video games do help, according to a review published recently online by the Cochrane Collaboration, an international nonprofit that provides up-to-date information on health care research.

Dr. Allan M. Cyna, an anesthesiologist at Women’s and Children’s Hospital in Adelaide, Australia, and his team pooled data from 17 studies involving 1,796 children ages 10 months to 17 years, their parents, or both.