The PARDI includes a screen, an introduction, and diagnostic and severity items for pica, ARFID, and RD. The purpose of the screen is to rule out the presence of other eating disorders (specifically, AN, bulimia nervosa [BN], binge eating disorder [BED], or a related form of other specified feeding or eating disorder [OSFED]) that would preclude a diagnosis of pica, ARFID, or RD per DSM-5 trumping rules (APA, 2013 ). The introduction includes items assessing growth and development, and physical and/or mental health conditions that would rule out a feeding disorder diagnosis, as well as the current pattern of feeding and/or eating. The remaining items are intended to inform the diagnostic algorithm (i.e., the combination of items that determine whether the participant meets criteria for pica, ARFID, or RD by DSM-5 criteria) and provide severity ratings for pica, ARFID, and RD. To assess the heterogeneity of ARFID specifically, the PARDI also contains three profiles with continuous ratings of severity for sensory sensitivity, lack of interest in eating, and fear of aversive consequences. These three PARDI profiles correspond with the three ARFID presentations described in DSM-5, which have been replicated in both clinical (Norris et al., 2018 (link)) and community (Kurz et al., 2016 (link)) samples. Based on our clinical experience that severity varies even within profiles, and that some patients with ARFID exhibit symptoms of more than one profile (Thomas et al., 2017 (link)), we opted for a dimensional rather than categorical approach to profile assessment.
Similar to the Eating Disorder Examination (EDE; Fairburn, Cooper, & O’Connor 2008 ), the majority of PARDI items are scored on a 7-point scale ranging from 0 (no symptoms) to 6 (severe symptoms). Like the EDE, the PARDI includes items assessing both the frequency and severity of relevant constructs. The remaining items invite responses that are either qualitative (e.g., “I would like to ask you about a typical day of eating and drinking. Starting with when you wake up, can you tell me about what you typically eat and drink throughout the day?”), or categorical (“Are you currently receiving any tube feeding?” with response options of yes or no). Table 2 provides an example item from each PARDI profile.
To support multi-informant assessment, there are four parallel versions of the PARDI: (1) Parent/Carer (2–3) (for the parents of 2–3-year-olds); (2) Parent/Carer (4+) (for the parents of 4-year-olds and up); (3) Child (for 8–13 year olds); and (4) Young person/Adult (for 14 year olds and up). Each version assesses the same constructs and contains similar items. However, the wording and response options have been adapted to include developmentally appropriate scenarios, vocabulary, and content. For example, only individuals less than 20 years old are asked about faltering growth. Specifically, both the Parent/Carer (2–3) and the Parent/Carer (4+) ask “Over the past 3 months has there been concern (e.g. from doctors, family etc.) that your child is not growing taller as he/she should?” In the contrast, the Child version asks “Over the past 3 months has your doctor or anyone in your family worried that you are not growing taller?” The Young/Person adult version asks the question in the same with as the Child version, with instructions from the interviewer to skip this item if the individual is 20 years or older.
When two versions of the interview are required, separate administration to parents and children is recommended. The PARDI rating sheet, as well as the Child and Young Person/Adult versions of the interview are freely available as an online supplement to the current article. Copies of the two Parent/Carer versions are available upon request from the first author (RBW).
Following administration of the PARDI, the diagnostic algorithms can be applied to the responses to generate diagnoses of pica, ARFID and RD. Similar to the EDE, the interview is designed as a semi-structured, investigator-based assessment tool, so that training in its use is recommended to maximize reliability.