Prevalence of severe mental distress and its correlates in a population-based study in rural south-west Uganda

Since 1986 Uganda has been recovering from decades of previous civil, political and economic turmoil. The estimated 30 million population are mostly engaged in subsistence agriculture. Annual Gross National Income is $300 per capita and mean life expectancy at birth is 50 years [15]. It is one of the countries in Africa where the HIV epidemic was first reported and that was initially most badly affected by HIV. The country has few psychiatrists (30 in number), fewer psychologist and psychiatric social workers with most of these confined to the capital city of Kampala and a few other urban centres. Outside the capital city of Kampala, formal mental health care is mainly provided by approximately 150 psychiatric clinical officers (physician assistants with a diploma in psychiatry) and psychiatric nurses [2, 3, 16].

The mental health services in the country are arranged around a primary health care model built on the integration of mental health care into a decentralized health-care delivery system at district level, through a system of Health Centres (HC) starting at village level, HC-I; subcounty level, HC-II; county level, HC-III; subdistrict level, HC-IV and district level, HC-V. This health structure is supported by a referral system which includes regional referral hospitals (which have a mental health unit, that should be staffed by a psychiatrist) and the national tertiary referral hospital at Butabika located in the capital city of Kampala [2, 3, 17]. Traditional beliefs about mental illness are still very strong in the country with many patients with mental illnesses first seeking care from traditional healers and in many cases this is the only mental health care that they will access [12].

The cohort comprises approximately 20,000 residents residents who live in 25 neighbouring villages in southwest Uganda a few kilometers from Lake Victoria. The vast majority of dwellings are distributed throughout the countryside rather than clustered in villages, which mainly represent administrative areas demarcated on maps rather than population centres. The study population are mostly subsistence farmers, whose staple diet consists of matooke (cooking bananas) with groundnuts. There are no tarmac roads and access may be difficult during the rains. People live in semi-permanent structures built from locally available materials. The community is stable and homogeneous, with most people from the Baganda tribe, and 15% of Rwandese origin, who are well assimilated. Religious affiliation is mostly Christian, with a significant Muslim minority (28%). Levels of literacy are low and the main income-earning activities are growing bananas, coffee and beans, and trading fish [18]. HIV seroprevalence reported in this study is a representation of the national picture [19]. HIV prevalence in the study area declined from 8.5% in 1990 to 6.2% in 1999/2000 but thereafter rose to 7.7% in 2004/2005 [20].

Since 1989 information has been collected in the annual cohort survey on HIV sero-prevalence and associated social, demographic and behavioural factors. Full details of the cohort and annual HIV serosurvey have been published elsewhere [21, 22]. In brief, an annual household survey has been conducted since 1989, with all study village residents eligible for inclusion. Average annual serosurvey participation is about 60%-65%, although a much higher percentage has ever participated. Community sensitization activities precede each survey round, including local council briefings and village meetings. All households are visited by, in turn, the mapping, census and survey teams. Consenting residents are interviewed at home in the local language by trained survey staff and provide a blood sample for HIV testing. Since 2009, the cohort has also served as a platform for epidemiological studies on a range of other health problems of public health importance.

In the 20^th annual survey round (December 2008 - November 2009), data were collected on the prevalence of selected non-communicable diseases (including diabetes, other cardiovascular disease risk factors, and SMD) in consenting adults (defined for the purpose of the survey as aged 13 years and above) [23]. Probable SMD was assessed using a composite screening question, 'Is there a time(s) when you experienced disturbances in your behaviour, thoughts or speech, e.g. shouting, undressing, running aimlessly, hearing voices of people who were not there?' This question was derived from the four screening questions for 'probable psychosis' as is given in the WHO Self Report Questionnaire-25 [10]. Study participants who responded positively to this question were advised to attend their nearest local health facility or the study clinic for further assessment. Additional questionnaire information collected included: sociodemographic factors; socioeconomic status (SES) measured using an asset index created by combining data on 22 household possessions using principal component analysis; whether a current or past regular cigarette smoker (including both manufactured and local cigarettes); ever consulted a traditional healer; and sexual behavior. Clinical and laboratory assessments were undertaken for: diabetes (plasma glucose measured using the enzymatic reference method with hexokinase; Roche COBAS Integra 400 analyser with Glucose HK Gen.3 reagent) [24]; hypertension [25]; HIV serostatus and epilepsy (possible epilepsy was assessed using the WHO-SRQ-25 derived question, 'do you have an illness characterized by recurrent episodes of falling to the ground associated with loss of consciousness ?') [10].

Data were double-entered and verified in Access. Stata 10 (Stata Corporation, College Station, USA) was used for analyses. Age-standardised prevalence of reported SMD was calculated by combining observed prevalence with age-stratified population estimates from the 2008 census round.

Factors associated with the observed prevalence of reported SMD were investigated using random effects logistic regression to account for correlation within households. A conceptual framework was used to consider potential determinants of and sequel to SMD (Figure 1), with factors classified into three groups: sociodemographic factors, behavioural and biological factors. A final explanatory multivariable model was not derived, since this was a cross-sectional study and it is not possible to establish causality, and many factors, such as marital breakdown, may be both possible determinants of, and sequel to, reported SMD. Instead, the association of factors of interest with reported SMD was examined, after adjusting for age and sex. These two variables were adjusted for as potentially important a priori confounders.

The study was approved by the Science and Ethics Committee of the Uganda Virus Research Institute and by the Uganda National Council for Science and Technology.

The majority (68.5%) of respondents were under 40 years of age. About half (55.7%) had less than 7 years of formal education and 42.8% were currently married. A fifth (20.5%) of males, but only 1.3% of females, were current or past regular cigarette smokers. Three quarters (75.3%) of females and 63.2% of the males were sexually active. A small minortiy (4.2% of males and 6.0% of females) had ever consulted a traditional healer.

On clinical factors, 0.6% of males and 0.3% of females reported they were suffering from epileptic illness. HIV positive serostatus was 4.8% in males and 6.9% in females. The prevalence of probable diabetes was 0.4% in both males and females, and of probable hyperglycaemia was 3.0% in males and 2.8% in females. Of the patients with severe mental distress (SMD) none of the males and only three of the females (5.7% of those with SMD) reported that they were receiving formal medical treatment for the SMD, so majority of people who report SMD are not getting treatment.

The observed prevalence of probable severe mental distress (SMD) (see Table 1) was 0.9% (95%CI = 0.6-1.1%), and was higher in males (1.1%, CI = 0.7-1.5) than in females (0.7%, 95%CI = 0.5-1.0%).

In the unadjusted analysis, socio-demographic factors with the strongest association with severe mental distress were increasing age and decreasing socio-economic status (Table 2). Participants who were 40-59 years old had nearly 4 times the odds of SMD as those under 20 years of age; however, the odds of SMD in those over 60 was similar to that in those under 20. Those who were in the lowest socio-economic quintile had 3 times the odds of SMD as those in the highest socio-economic quintile. There was some evidence that females were less likely to have SMD than males (age-adjusted OR = 0.58, CI = 0.33-1.01, p = 0.05). After adjusting for age and sex, SES was the only sociodemographic factor that remained associated with SMD.

In the unadjusted analysis, behavioural factors significantly associated with SMD were: being a regular smoker (OR 3.2, CI = 1.46-6.93, p = 0.008); number of sexual partners in the last year (those with none, or with two or more, sexual partners were more likely to report SMD than those with only one); and ever consulted a traditional healer (OR 4.1, CI = 1.94-8.58, p = 0.001). There was no evidence that age at first sexual encounter was associated with SMD After adjusting for age and sex, the significant association between the number of sexual partners in the last year, and consulting a traditional healer, with SMD remained, and there was weak evidence of an association with smoking.

Of biological factors, there was an extremely strong association between reported epilepsy and SMD, a relationship which remained significant even after adjusting for age and gender (P < 0.001). There was no evidence of an independent association with HIV serostatus, hypertension or diabetes with SMD in this study.