Major depressive disorder was prevalent in our study population, occurring in 17.4% of the participants. Previous studies conducted among PLWHA in Uganda have reported higher depression prevalence 
; findings which could be explained by the fact that in those studies, the diagnosis of depression was made using a screening instrument, rather than a diagnostic one. Our population comprised of medically stable participants who were generally healthier, and this could explain the lower prevalence compared to the other Ugandan studies..
AIDS-related stigma, a condition that has been associated with adverse health outcomes in PLWHA was equally prevalent in the study population. Our finding about AIDS related stigma is also in keeping with previous studies that have reported a high burden of stigma in PLWHA 
We found an association between major depressive disorder and AIDS related stigma, meaning that both conditions may be present in the same HIV-positive individual attending PHC. Our findings are in keeping with a previous study that documented an association between depression and stigma in PLWHA 
. Poor psychosocial functioning, the presence of opportunistic infections, poor immune status and the fear of dying from a chronic illness could explain the existence of either of these conditions, as well as their association with each other. Previous studies have reported that stigma among PLWHA is associated with poor psychosocial functioning 
. It's possible that people with poor psychological functioning may develop depression.
Similarly, the presence of opportunistic infections and poor immune status has been associated with depression in PLWHA 
. It can also be argued that depressed PLWHA who have opportunistic infections and low CD4+ counts could develop stigma as a result of their condition. The fear of dying from a chronic illness may also explain the presence of both conditions. However, the cross-sectional nature of our study makes it difficult to establish causality, and the direction of the development of each condition.
Our findings regarding the association between major depressive disorder and low CD4 counts are in keeping with previous studies 
. These findings could be explained by the fact that late stage disease (manifested by low CD4 counts) may have an aetiological role in the development of depression among PLWHA. The presence of depression in PLWHA could also lead to a decline in CD4 levels; such an association has been previously documented 
. It's also possible that the sicker PLWHA become, the more likely they are to report symptoms of major depressive disorder. More work is needed to examine such hypotheses.
The association between major depressive disorder and younger age contradicts previous studies where major depressive disorder was particularly common in older people attending PHC services 
. Perhaps the different contexts in which HIV/AIDS manifests could explain such differences. Specific neurobiological factors may play a role in contributing to major depressive disorder in older subjects; further work is needed to explore this hypothesis.
A number of limitations in this study deserve emphasis. We utilised a cross-sectional design, so that causality cannot be fully addressed. A longitudinal follow-up study could provide better insight into the precise nature of the relationship between depression, and the studied factors. That said, PLWHA should be assessed for both major depressive disorder and AIDS related stigma since both conditions may present concurrently in the same individual.
Secondly, the study was conducted in a single PHC site, and may not be representative of the burden of major depressive disorder in PLWHA in Uganda.
Thirdly, we didn't abstract information regarding patients being on ART, despite the fact that a number of PLWHA at the study site were accessing ART. This information could have given us better insight into its relationship with depression and stigma.
Fourth, the instruments we used including the MINI, AIDS stigma scale, and the PHQ-9 haven't been validated in Uganda. This could have led to some inaccuracies in our findings. However, a number of studies have been conducted in Uganda using the MINI, and have reported similar prevalence findings to our study 
Despite these limitations, this study reports on the association between major depression, AIDS stigma and a number of variables among PLWHA in sub-Saharan Africa. Clinicians working in HIV settings should regularly assess for both depression and stigma among clinic attendees, since these conditions may be present concurrently in PLWHA.
In conclusion, due to the high burden of major depressive disorder, and its association with AIDS related stigma among PLWHA, routine screening of PLWHA for both conditions is recommended. However, further work may be required to understand the complex relationships between AIDS stigma and major depressive disorder. Further work to disentangle the relationships between major depressive disorder and low CD4 counts is equally needed.