Using the South African Depression Scale (SADS) to measure depressive symptoms in a UK sample

Background The South African Depression Scale (SADS) was recently developed by Andersen and colleagues1 2 as a screening tool for depressive symptoms specific to Xhosa culture. This scale was designed to assess classical symptoms of depression which are also measured by other tools such as the 9-item Patient Health Questionnaire (PHQ-9), including sleeping issues and anhedonia. Additionally, the SADS assesses more idiomatic expressions of depression, such as ‘having pain in my heart’ or ‘carrying a lot of weight on my shoulders’, which the PHQ-9 does not capture. The SADS has so far only been validated in South African cohorts of people living with HIV, but as this questionnaire was developed in both English and isiXhosa, it is possible to apply it to populations outside South Africa. Assessing the reliability of the SADS in other countries and cultures may further support the utility of this scale and enable comparisons with studies conducted in populations outside South Africa.

Methods In this pilot study, we recruited n=20 adults living with HIV (median (IQR) age 50.5 (45.0, 54.0) years, 95% male, 80% self-identifying as White) in Brighton, UK. All participants were residing and receiving their regular HIV-related clinical care in Brighton, and none identified as Xhosa. To determine whether the SADS performed satisfactorily for participants with low or high severity of depressive symptoms, participants were recruited in two groups: low depression severity (PHQ-9<7, n=9) or high depression severity (PHQ-9>15 and a history of receiving antidepressant medication). All participants completed the PHQ-9 and the SADS in English during a single visit. In R v.4.3.2, we assessed the internal consistency of the SADS using Cronbach’s α, convergent reliability with the PHQ-9 using Pearson’s correlation coefficient (r) and item-level performance using descriptive statistics and item–total correlations. All participants had access to a dedicated HIV mental health service, including psychologists and psychiatrists, and were referred to this service if they exhibited suicide ideation or other symptoms which required referral.

Results In our UK-based sample, the SADS exhibited high internal consistency, Cronbach’s α=0.975 (95% CI 0.955, 0.988). Total score on the SADS was strongly and significantly correlated with total score on the PHQ-9 (r=0.97, p<0.001) (figure 1).