Page 44 - The efficacy and effectiveness of psychological treatments for eating disorders - Elske van den Berg

44 Chapter 2
Discussion
In this meta-analysis, the efficacy of psychological treatments for anorexia nervo- sa compared with a control condition was examined. The results suggest that with regard to weight gain, eating disorder pathology, and QoL, no differences between psychological treatment and control condition are found. Studies including only patients over 18 years of age were more effective on weight gain than studies includ- ing adolescents as well. High-quality studies (i.e. studies which are methodological- ly robust) differed significantly from low-quality studies with regard to weight gain. In addition, with regard to QoL, high-quality studies and studies in which therapist training was reported, differed significantly from low-quality studies and studies without reported training. However, including only high-quality studies in the meta-analyses did not establish a significant difference between psychological and control conditions.
The main finding of not being able to establish differences between psycho- logical treatment and control conditions with regard to weight gain and/or eating disorder pathology is in line with previous studies (Hay, Claudino, Smith, et al., 2015; Zeeck et al., 2018). Adding recent, large RCTs, as we did in this meta-analysis, did not result in a different finding. The recent meta-analysis of Murray (Murray et al., 2018) found that specialist treatments (not just psychological treatments) showed a signifi- cant treatment effect over control conditions with regard to weight-based symptoms improvement at end-of-treatment, although at follow up this difference did not last. The results suggest that the field still lacks psychological interventions of enough strength for added value to be detected.
At the same time, it seems that low-quality studies obscure the effects of psycho- logical treatment. The finding that high-quality studies differ significantly from low-quality studies with regard to weight gain and QoL, suggests that psychological interventions can have additional benefits over and above control treatment.
In addition, the lack of difference between psychological and control condition may also be related to the fact that included studies are heterogeneous; even the recent large, methodologically sound RCTs are heterogeneous and show contradic- tory findings. Furthermore, the lack of difference can possibly be explained by the nature of the control conditions. The control conditions in this meta-analysis consist- ed of multimodal interventions in line with recommended core elements for anorex- ia nervosa treatment, such as engaging the patient, nutritional & physical rehabilita- tion and structured psychological interventions (Hay Claudino, Smith et al., 2015). By using such plausible active control conditions, it is hard to distinguish the additional benefits of psychological treatment for anorexia nervosa.