Nearly three in every five prisoners experience common mental disorders (CMDs) in Jimma correctional institution; south-West Ethiopia

A sample of 302 prisoners was calculated using single population proportion formula by considering the following parameters: Proportion (P) of individuals with common mental disorders from previous study in Ethiopia, 67.60%, z = standard score corresponding to 95% confidence level to be 1.96 and d = margin of error 5% (0.05). These parameters were combine together through the equation, n = \( \frac{{\boldsymbol{z}}^{\left(\boldsymbol{\alpha} /\mathbf{2}\right)\mathbf{2}}\boldsymbol{p}\ \left(\mathbf{1}-\boldsymbol{p}\right)}{d^2} \) which yields n = 340. This was further corrected to total prison population which was 1460 prisoners in the year 2017; yielding 302. Finally, systematic random sampling technique was employed to draw a total of 302 participants from a sampling frame consisting of 1460 prisoners.

Data were collected by using a structured questionnaire through interviewer administered basis. The questionnaire had six sections. The first section was socio-demographic dimension. The other section covered assessment of mental disorders which was measured by the World health organization Self Reporting Questionnaire (SRQ-20) scale to assess prevalence of mental disorders [25]. The scale addressed the overall physical, psychological and social symptoms of mental disorders among prisoners. Despite the scale was designed mostly for self-administered approaches; was also found to be suitable for interviewer administered questionnaire especially in settings with low literacy rate in developing countries like Ethiopia [26]. It has 20 items scaled as zero or one (0 or 1) each. A score of one (1) indicate that the symptom felt present during the past month and score zero (0) indicate that the symptom absent [25].

One of the challenges with this scale was its poor predictive validity across culture and context especially when the score of 7/8 cut off point is employed. This cut-off point tends to underestimate prevalence of mental disorders especially among women [27]. However; the scale demonstrated better validity in culture of developing nations including Ethiopia [26]. However; since the SRQ-20 is not a diagnostic tool; the use of cut off point doesn’t matter as it is enough to establish the mental health profile of a given population at a given time. With our study; since the aim was to screen out prisoners with suspected mental disorders, the prevalence of CMDs could be better estimated from a cut off point defined; according to the number of positive responses for symptoms. Subjects were classified as suspected cases when they had cut off point eight or more positive responses to items so that to give meaningful interpretation and explicit recommendation for policy advocacy.

Another important dimension recommended to be included in mental disorder measurements is; the social support dimension. This was measured using the Oslo-3 scale questionnaire on five point Likert scales ranging from; 1 = strongly disagree to 5 = strongly agree [28]. For the sake of convenient analysis; the score was calculated for three categories of level of social support as (< 4 = poor, 4–9 = moderate and > 9 high). The questionnaire was prepared in English and translated to a local language Afan Oromo. The reliability coefficient for the general OSLO-3 scale was Cronbach’s alpha of 0.73 which was considered acceptable level [29].

Three hundred; out of 302 respondents have completed the study yielding 99.3% response rate. Two hundred eighty one; 281 (93.7%) participants were males. The mean age of the respondents was 30 (±12) years. Majority of the respondents; 174 (58%) were Muslims followed by Christian orthodox; 94 (31.3%). The Oromo Ethnic group encompasses majority with 199 (66.3%) followed by Amhara ethnic group; 43 (14.3%). Almost half; 157 (52.3%) of respondents were single and many; 160 (53.3%) of them had primary level educational experiences. About; 86 (26.7%) were farmers. The majority 191 (63.7%) of the respondents were living in urban before prison and 125 (41.7%) have children (Table 1).

The prevalence of CMDs among prisoners as measured on SRQ-20 scale was considerably high with 188 (62.70%); 95% CI [57.30, 68.50%]. Females were less affected as only 14 (4.70%) experienced CMDs compared to males; 174 (58%). Specifically within the SRQ-20 score; loss of interest, loss of sleep and unhappiness were indicted as major mental symptoms reported. Importantly; symptoms like trouble thinking, feeling of worthless and nervousness were also observed salient symptoms in the present study (Insert Fig. 1).

The analysis began with bivariate logistic regression analysis in which explanatory variables with p-value less than 0.05 were selected for multivariate logistic regression models to control for possible confounding. Accordingly; fifteen variables namely; age category, marital status, occupation before prison, monthly income before prison, time spent in person, type of current crime committed, previous incarceration, religion, work status in prison, perceived social support, self-reported chronic physical illness, family history of mental illness, ever use of Khat, ever use alcohol and ever smocking were variables which demonstrated significant association with CMD in bivariate logistic regression analysis.

However on multivariate logistic regression modeling; only five variables namely; monthly income and having family history of mental illness, ever use of Khat, having worked in prison and social support were emerged to be significant predictors of CMDs. Accordingly; prisoners who had monthly income of 1500–3000 birr; AOR = 3.30, 95% CI; [1.25, 8.69] and above 3000birr; AOR = 4.75, 95% CI; [1.57, 14.33], family history of mental illness; AOR = 6.14, 95% CI; [1.65, 22.79] and who ever used Khat; AOR = 4.33, 95% CI; [2.02, 9.27] were found more likely to have common mental disorders. In-contrast; having some sort of work in prison; AOR = 0.25, 95% CI; [0.12, 0.54], perceived moderate and strong social support; AOR = 0.094, 95% CI; [0.04–0.215], AOR = 0.025, 95% CI; [0.009, 0.07] respectively; were found less likely to have common mental disorders. (Table 2).

First; the study has employed cross-sectional study design in which it’s difficult to establish cause and effects relationships. Due to the vulnerable nature of the study setting; the possible influence of social desirability bias on the result should be considered while interpreting the finding. On top of this; the study couldn’t examined the pre-existing mental illness and hence should be considered as limitation. Furthermore; majority of scales previously used for the assessment of mental health status at clinical and community settings performing varying degree of validity across settings, populations and cultures. These scales are the Beck Depression Inventory (BDI-II) scale, the structured clinical interview for depression in DSM-5, comprehensive psychopathological rating scale, and the SRQ-20 were few among many [27, 41‐43]. Despite it has many limitations; the SRQ-20 demonstrated better validity in culture of developing nations including Ethiopia [26]. These limitations are primarily related to the type of analysis method employed. The cut off point method (Score > 8) which was considered in the current as well; does not provide detailed knowledge of the contribution of each dimension of depression/anxiety, somatic symptoms, reduced vital energy, depressive thoughts. However; since the SRQ-20 is not a diagnostic tool; the use of cut off point doesn’t matter as it is enough to establish the mental health profile of a given population at a given time. Furthermore; study have showed that the cut off point SRQ-20 tends to underestimate prevalence of mental disorders among women [27].

Recognitions and assessment of prisoners for CMDs up on their arrival and targeted follow up screening and treatment should be done regularly. Further; creating some sort of jobs that could bring prisoners together and encouraging them to create positive relationships so as to build sense of social supports and self-efficacy to coping with possible stresses is required. Furthermore, large scale longitudinal research should be launched to track the process of CMDs development and infer the causal and effects.