Depression, anxiety and distress are common during the course of cancer. Studies suggest prevalence of distress greater than 30%. Distress and depression influence quality of life. However, depression is often overlooked by cancer professionals. It is needed short and easy instruments to help to assess depression symptoms and its severity. PHQ-9 is an example of a short instrument to assess depressive symptoms and its severity.

In this work the preliminary study of the psychometric characteristics of PHQ-9 in a sample of breast cancer Portuguese women is described.

We purpose to evaluate psychometric characteristics of PHQ-9 in a Portuguese sample, namely: internal consistency, test-retest reliability and concurrent validity.

Psychometric analyses were performed on a sample composed of 49 breast cancer women, with ages from 30 to 80 years old (M = 59.27, SD = 11.12). Participants answered to PHQ-9 twice (with a 2 months interval) and once to Hospital Anxiety and Depression Scale (HADS). The procedure enclose: translation; back translation; discussion group for inspection of lexical equivalence and content validity and application to a target population.

It was obtained a Cronbach alpha of .82. The test-retest reliability show a significant statistical positive correlation (rS = .82, p = .000). Significant positive statistical correlation with HADS was also observed (rS = .60, p = .000 for anxiety and rS = .65, p = .000 for depression).

The validation of the Portuguese PHQ-9 has good psychometric proprieties of internal consistency, test-retest reliability and concurrent validity. Therefore, we can conclude that PHQ-9 is a useful and a valid scale.