[Psychometric properties of the Questionnaire de Fonctionnement Social in borderline personality disorder]

Social functioning is a primordial aspect of mental health and it should be considered as an important outcome measure in psychiatric treatments and studies. Few short and simple assessment instruments are available in French. Recently, the Questionnaire de Fonctionnement Social (QFS) was developed to study social behavior of psychiatric patients. The QFS is a 16-item self-report questionnaire assessing the frequency of and the satisfaction with social behavior during the last two weeks. The aim of the present study is to explore QFS psychometric properties in a sample of patients with borderline personality disorder.

Eighty-six outpatients (78 women and eight men, mean age: 30.5+/-8.6) with borderline personality disorder and 100 healthy matched control subjects (89 women and 11 men, mean age: 30.2+/-7.7) completed the QFS. The convergent and divergent validities of the QFS were tested with the following instruments: Social Adaptation Self-Evaluation Scale (SASS), Brief Symptom Inventory (BSI), Beck Depression Inventory (BDI), Beck Hopelessness Scale (BHS) and a visual scale of suffering (EVS). Test-retest reliability of the QFS was calculated in a sub-sample of 28 subjects and its sensitivity to change was measured for 45 patients.

Internal consistency of the QFS' global index was satisfying (Cronbach alpha from 0.59 to 0.84). Test-retest reliability of the QFS indexes ranged from 0.77 to 0.79 (intraclass correlation coefficient). Correlations between QFS and SASS demonstrated moderate convergent validity (r>0.59) whilst associations with others psychological measures (BSI, BDI, BHS, EVS) showed satisfying divergent validity (-0.42

The QFS demonstrated satisfying psychometric properties in the studied population. This study confirms it is a valuable tool to assess social functioning of borderline personality disorder patients.