Psychometric properties of the DASS-Depression scale among a Brazilian population with chronic pain

BackgroundDepression is a common contributor to suffering and disability in people with chronic pain. However, the assessment of depression in this population has been hampered by the presence of a number of somatic symptoms that are shared between chronic pain, treatment side-effects and traditional concepts of depression. As a result, the use of depression measures that do not contain somatic items has been encouraged.ObjectiveThis study examined the psychometric properties of the Depression sub-scale of the Depression Anxiety and Stress Scales (DASS) in a Brazilian chronic pain patient population.MethodData on a number of measures were collected from 348 participants attending pain facilities.ResultsPrincipal components and exploratory factor analyses indicated the presence of only one factor. Item analyses indicated adequate item-scale correlations. The Cronbach α was .96, which suggests an excellent internal consistency.ConclusionThe DASS-Depression scale has adequate psychometric properties and its further use with Brazilian chronic pain populations can now be supported.