Adaptation and validation of the depression, anxiety and stress scale (DASS) to Brazilian Portuguese

Depression and anxiety have been associated with a range of symptoms that often overlap. Depression, Anxiety and Stress Scale-21 (DASS-21) is a single instrument to assess symptoms of depression, anxiety and stress. This study aimed to adapt and validate the DASS-21 for use in the Brazilian Portuguese language.The DASS-21 has been adapted following the translation-back translation methodology from English to Portuguese. 242 subjects completed the following assessments: the DASS-21, the Beck Depression Index (BDI), Beck Anxiety Index (BAI) and the Inventory of Stress Symptoms of Lipp (ISSL).The Kaiser-Meyer-Olkin (KMO) result was .949, indicating that the adequacy of the model was high. Cronbach's alpha was .92 for the depression, .90 for the stress, and .86 for the anxiety, indicating a good internal consistency for each subscale. The correlations between DASS scale and BDI scale, BAI scale and ISSL inventory were strong. The factorial analysis and distribution of factors among the subscales indicated that the structure of three distinct factors is adequate.Older subjects over 65 years of age were not largely represented in this sample. A study specific to this elderly population should be conducted. Another limitation of the study was education level. The impact of low education in its applicability should be considered.The findings support the validity of the Brazilian Portuguese version of the DASS-21 and add to the evidence of the DASS-21 quality and ability to assess emotional states separately, eliminating the use of different instruments to assess these states.