Development and validation of an Eating Disorders Symptom Impact Scale (EDSIS) for carers of people with eating disorders

Background: Family members of relatives with eating disorders experience high levels of distress due to the difficulties in their care giving role. However no measures have been developed to measure the specific impact that an individual with an eating disorder has on family life. The aim of this study was to develop a measure to assess the specific caregiving burden of both anorexia nervosa and bulimia nervosa. A secondary aim was to examine whether this measure was sensitive to change. Methods: A new scale, the Eating Disorders Symptom Impact Scale (EDSIS), was generated by a panel of clinicians and researchers based upon quantitative and qualitative work with carers and reviewed by a panel of "expert carers". A cross-sectional study was conducted among carers of relatives with an eating disorder to examine the properties of the new scale. In addition, participants from an ongoing pre-and-post design study completed several self-report questionnaires to assess the sensitivity of the EDSIS to change. Results: A sample of 196 carers of relatives with an eating disorder aged 25-68 compted the scale. A 24-item EDSIS scale was derived with four factors: nutrition, guilt, dysregulated behaviour and social isolation. These explained 58.4% of the variance in carer distress. Reliability was acceptable (Cronbach's alpha ranged from 0.84 to 0.90). The convergent validity of the EDSIS subscales was moderately supported by correlations with a general caregiving measure (Experience of Caregiving Inventory (ECI), r = 0.42 to 0.60), psychological distress (General Health Questionnaire (GHQ-12), r = 0.33) and perceived functioning of the relative (Children Global Assessment Scale (CGAS), r = -30). A sample of 57 primary caregivers completed pre-post intervention assessments and the overall scale (t = 2.3, p < 0.05) and guilt subscale (t = 3.4, p < 0.01) were sensitive to change following a skills training workshop. Conclusion: The EDSIS instrument has good psychometric properties and may be of value to assess the impact of eating disorder symptoms on family members. It may be of value to highlight carers' needs and to monitor the effectiveness of family based interventions.