This study aimed to test the validity of the 21-item Depression Anxiety Stress Scales (DASS-21) as a routine clinical outcome measure in the private in-patient setting. We hypothesized that it would be a suitable routine outcome instrument in this setting.

All in-patients treated at a private psychiatric hospital over a period of 24 months were included in the study. Data were collected on demographics, service utilization, diagnosis and a set of four routine measures both at admission and discharge. These measures consisted of the Clinical Global Impressions (CGI) scales, Health of the Nation Outcome Scales (HoNOS), the Mental Health Questionnaire (MHQ-14) and DASS-21. The results of these measures were compared.

Of 786 admissions in total, the number of fully completed (ie paired admission and discharge) data sets for the DASS-21 depression, anxiety and stress subscales were 337, 328 and 347, respectively. All subscales showed statistically significant reductions in mean scores from admission to discharge (P < 0.001) and were significantly correlated with all MHQ-14 subscales and significantly related to CGI scale categories. The total DASS-21 and total HoNOS scores were also significantly correlated.

The findings from the present study support the validity of DASS-21 as a routine clinical outcome measure in the private in-patient setting.