Fisher CA, Skocic S, Rutherford KA, et al. Cochrane Database Syst Rev. 2019 May 1;5:CD004780. doi: 10.1002/14651858.CD004780.pub4. (Systematic review)

Mainly due to criticism of methodological limitations of included studies, this Cochrane review offers greater caution and less optimism than previous systematic reviews about the benefits of family therapy approaches for anorexia nervosa.  Included were 16 adolescent and 8 adult studies.  No influence of participant age was found upon overall results.  There was evidence of a small effect favouring family based therapy over other types of therapy in terms of weight gain post-intervention.

https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD004780.pub4/full