The paper sought to investigate the prevalence and the psychological, social and biological risk factors of major depressive disorder (MDD) in HIV/AIDS in the African socio-cultural context. The principal finding of this study is that among ambulatory HIV/AIDS patients in the sub-Saharan African environment of Uganda, psychosocial impairment, increasing negative life events and the co-morbid psychiatric disorders/problems of post traumatic stress disorder, generalised anxiety disorder and life-time attempted suicide were the strongest independent determinants of MDD. Also associated with an increased risk for MDD in this study were the following psychological (family history of psychiatric disorder, negative coping style, alcohol dependency disorder), social (food insecurity, stress, poor social support) and socio-demographic (female gender) factors. In this study none of the investigated markers of direct HIV involvement including of the central nervous system (neurocognitive impairment, CD4 counts and BMI) were significantly associated with MDD. These results suggest while psychological and social factors were important risk factors for MDD among ambulatory HIV/AIDS persons in this socio-cultural environment, there was no evidence to support the role of the neurotoxic effects of HIV in MDD this sub-population of HIV/AIDS patients.
The prevalence of major depressive disorder obtained in this study was 8.1% a figure comparable to that of 9.6% reported by Chisanga et al (2011) in Zambia, 11.4% reported by Adewuya et al (2007) in Nigeria and 2.7% reported by Marwick and Kaaya (2010) in rural Tanzania [9
]. All three studies above derived from sub-Saharan Africa used international diagnostic criteria to make a diagnosis of MDD just like we did in this study. However the picture on prevalence of MDD in HIV/AIDS is more complex than this, other studies undertaken both in South Africa and more recently in Uganda that used international diagnostic criteria reported rates of MDD as high as 40% [5
]. This wide variability in rates of MDD has previously been noted by Judd and colleagues (1994) in a review of studies on MDD in HIV/AIDS [22
]. Judd and colleagues (1994) attributed this wide variations in rates of MDD to a number of factors many of which are still relevant today, these included: methodological challenges in assessing MDD in somatically ill patients; differences in the composition of the study samples on 'at risk groups' (commercial sex workers, injection drug abusers, men who have sex with men, discordant couples, high risk occupational groups such as fisherfolk, and persons who acquired HIV perinatally) and on the different HIV clinical stages; whether the study population was predominantly in-patient or out-patient; and geographical differences [22
]. Judd et al. (1994) summarised their observation by stating that it was not yet possible to come to a clear conclusion about the prevalence of MDD in HIV/AIDS, a summary which still seems to be pertinent to the sub-Saharan African setting today [22
In this study female gender conferred a twofold increased odds for MDD relative to the male gender. A positive association between female gender and MDD in HIV/AIDS has previously been reported in Africa by both Kaharuza et al (2006) in Uganda and Orley et al (2004) in South Africa [6
]. Some of the gender differences in MDD have been attributed to the more likelihood of females than males to become victims of traumatic experiences such as sexual, physical and emotional abuse both in childhood and in adulthood [23
]. Indeed in this study females reported more negative life events than males and adjusting for the more proximal factors of negative life events and increasing stress scores greatly attenuated the association of female gender with MDD. Contrary to a common finding in research in this area [24
], adjusting for social support in this study did not reduce the strong association between MDD and negative life events nor the strong association between MDD and stress scores indicating that social support did not moderate these effects in this study.
The significant association between MDD and food insecurity has previously been described in both low and high income settings [25
]. The exact direction of causality between MDD in HIV/AIDS and food insecurity and the underlying mechanisms are not known and should be investigated. Possible explanatory mechanisms include food insecurity (in low income settings) leading to intense competition for scarce resources and in the process undermining social solidarity; other studies have pointed to a possible role for the associated micronutrient deficiency in the aetiology of MDD in HIV/AIDS [27
In this study a negative coping style was associated with MDD. In HIV/AIDS, negative coping styles such as the use of avoidant strategies has been shown to be associated with MDD [29
]. A positive family history of mental illness was shown to be associated with MDD in this study. Judd and colleagues (2005) in Australia observed a positive trend for the influence of a family history of psychiatric problems and MDD although this did not attain statistical significance [11
]. The observation in this study of a significant association between family history of mental illness and MDD suggests a possible role for genetic predisposition to MDD in this sub-population of HIV/AIDS patients. Various genetic polymorphisms including those involving the serotonin transporter gene have been previously associated with increased vulnerability to MDD in the general population in the context of psychosocial stress [30
]. There is however need to determine the specific mechanisms underlying genetic vulnerability to MDD among ambulatory HIV/AIDS patients in this environment. Psychosocial impairment was significantly associated with MDD in this study. In both Orley's studies in South Africa, impaired psychosocial function was significantly associated with MDD [4
]. In this study just like in Orley's studies it was not possible to determine the direction of causality between impaired psychosocial function and depression due to the cross-sectional study design.
In this study comorbid psychiatric disorders/problems of PTSD, generalized anxiety disorder, alcohol dependency disorder and life-time attempted suicide were significantly associated with MDD. Given the cross sectional design of this study, it was not possible to determine the direction of causality between these comorbid psychiatric disorders and MDD in this study. However in a prospective study in the US, Atkinson and colleagues (2008) reported that lifetime multiple psychiatric comobidity was the most potent predictor of incident MDD episodes among HIV infected men [31
Neurocognitive impairment in this study, though high, was not associated with MDD. A similar observation was made by Atkinson and colleagues (2009) in the U.S.A. and Judd and colleagues (2005) in Australia [11
]. None of the markers of HIV disease progression (CD4 counts and BMI) was significantly associated with MDD in this study. Akena and colleagues (2010) in their study in Uganda observed no association between MDD and CD4 counts [32
]. Ciesla and Roberts (2001) in a meta-analysis involving 10 studies concluded that HIV stage was not a factor in MDD [33
The findings from this study whereby neurocognitive impairment and markers of HIV disease progression were not significantly associated with MDD suggest that there is a minimal role for the neurotoxic effects of the HIV virus in the aetiology of MDD in ambulatory HIV patients in this socio-cultural environment. Judd and colleagues (2005) in Australia among 'well' PLWHA made a similar observation [11
]. However to confirm this observation will require the study of more specific and sensitive markers of HIV associated inflammation such as the pro-inflammatory proteins [10
There is however evidence from studies both undertaken in Uganda and an earlier study undertaken in the US for a possible neurotoxic role of HIV in the aetiology of MDD [10
]. Two study groups in Uganda (with one involving the author, EK) have reported evidence for HIV associated organic affective disorder syndromes among HIV positive persons with severe mental illness [34
]. Earlier in the US, Lyketsos and colleagues (1996) in a longitudinal study reported a dramatic sustained rise in depressive symptoms18-24 months before the onset of clinical AIDS a phenomenon they attributed to the widespread dysregulation of the immune system around this period [10
]. These results taken together suggest a possible neurotoxic role of HIV in the aetiology of MDD. There is however need for more research in this area to better understand this phenomenon.