Qualitative Research on Fatigue Associated with Depression: Content Validity of the Fatigue Associated with Depression Questionnaire (FAsD-V2)

BACKGROUND: Fatigue is one of the most common symptoms of major depressive disorder (MDD). The Fatigue Associated with Depression Questionnaire (FAsD) was developed to assess fatigue and its impact in patients with MDD. The current article presents the qualitative research conducted to develop and examine the content validity of the FAsD and FASD–Version 2 (FAsD–V2). METHODS: Three phases of qualitative research were conducted with patients recruited from a geographically diverse range of clinics in the US. Phase I included concept elicitation focus groups, followed by cognitive interviews. Phase II employed similar techniques in a more targeted sample. Phase III included cognitive interviews to examine whether minor edits made after Phase II altered comprehensibility of the instrument. Concept elicitation focused on patients’ perceptions of fatigue and its impact. Cognitive interviews focused on comprehension, clarity, relevance, and comprehensiveness of the instrument. Data were collected using semi-structured discussion guides. Thematic analyses were conducted and saturation was examined. RESULTS: A total of 98 patients with MDD were included. Patients’ statements during concept elicitation in phases I and II supported item development and content. Cognitive interviews supported the relevance of the instrument in the target population, and patients consistently demonstrated a good understanding of the instructions, items, response options, and recall period. Minor changes to instructions for the FAsD–V2 did not affect interpretation of the instrument. CONCLUSIONS: This qualitative research supports the content validity of the FAsD and FAsD–V2. These results add to previous quantitative psychometric analysis suggesting the FAsD–V2 is a useful tool for assessing fatigue and its impact in patients with MDD.