A family's experience of mental illness can change the family's functioning. In clinical contexts, valid and reliable instruments that assess family functioning, therapeutic changes, and the effects of family nursing interventions are needed. This study focuses on the linguistic and cultural adaptation of the Iceland-Expressive Family Functioning Questionnaire (ICE-EFFQ) to European Portuguese and examines the psychometric properties of this instrument. A non-random sample of 121 Portuguese depressed patients and their relatives completed the questionnaire. Principal components analysis extracted 4 factors, explaining 55.58% of the total variance. Confirmatory factor analysis revealed acceptable adjustment quality indices. Cronbach's alpha coefficient was adequate for the global scale α = .86 and for the 4 subscales: communication α = .79, expression of emotions α = .68, problem-solving α = .71, and cooperation α = .61. The Portuguese version of ICE-EFFQ is a sensitive, valid, and reliable instrument for use with Portuguese families with adult members with depression and can be valuable in assessing these families' expressive functioning, before and after intervention.
Keywords: Iceland-Expressive Family Functioning Questionnaire; depression; expressive family functioning; psychometric testing.