Common mental disorders (CMDs) are groups of distress states that include anxiety, depression, and unexplained somatic symptoms, which are characterized by symptoms such as insomnia, fatigue, irritability, forgetfulness, difficulty concentrating, and other somatic complaints that may have a permanent impact on human life (1). They often co-occur with a fluctuating collection of symptoms that indicate emotional or mental abnormalities throughout the time that result in impairment of personal functioning (2, 3).

The worldwide burden of disease and disability is significantly impacted by common mental disorders, which are responsible for 14% of the overall disease burden (3, 4). They have been documented as being of the greatest public health concern, with an estimated 450 million individuals suffering from the problem worldwide (5). These common mental disorders (CMDs) have negative social and economic consequences in addition to a considerable functional disability (6, 7). By the year 2030, it is expected to be the main cause of illness burden. They have been well known as having frequent co-morbidities with other disorders (8). Of these frequent co-morbid mental diseases, depression and anxiety make up a higher percentage (8, 9). According to reports, women are more likely to develop CMDs than males, particularly in low- and middle-income countries (10, 11). Common mental disorders are more prevalent in low- and middle-income countries, with an estimated prevalence of 48.6% (12).

Although the prevalence of various mental disorders varies from one country to another countries, it is believed that 15 to 20% of all prisoners experience mental illness at any given time (13). Compared to the general population, serious psychiatric problems are 10 times more prevalent in correctional facilities, which is a higher prevalence than would be expected (14). Consistently, prisoners from numerous different countries are reported to have high rates of mental illness (15, 16). The overall magnitude of CMDs is high among prisoners, with ranges of 13 to 92.5% (17). Prison environments are characterized by stressful situations, overcrowding, violence, and isolation that expose inmates to loss of liberty, separation from family and friends, failure to maintain prior lifestyles and feelings of guilt and humiliation. As a result, many mental problems that may have already existed before imprisonment may get worse during incarceration (4, 18). People with mental illness are eight times more likely to experience sexual abuse in prison than prisoners without mental illnesses (19, 20).

Different studies in the world showed that common mental disorders are high among prisoners. Around 20% of female convicts and approximately 50% of male prisoners are estimated to have mental illnesses globally (21). European studies have revealed that 90% of inmates in the UK and 40% of prisoners in France experience mental health problems (22). In Hong Kong, 51.0 and 39.6% of lifetime histories of mental disorders and current mental disorders, respectively (23). According to studies conducted in various parts of the world, the prevalence of CMD is 65.3% in England, (23) 84.4% in India (24), 64% in the United States (25), 75% in Germany (26), and 73% in Canada (27). As previous studies conducted in Ethiopia, the prevalence of common mental disorders among prisoners varies largely and ranges from 37.9% (28) to 83.4% (29).

Epidemiological studies have identified several factors that are associated with common mental disorders among prisoners such as social exclusion, overcrowded prison settings, loss of autonomy, deprivation of decision-making, and loss of freedom and inadequate healthcare provisions in correctional service facilities (10, 30, 31). Low socioeconomic level, psychological illness, poor reproductive health, gender inequality, and physical disease are also risk factors for the common mental disorder (14, 30). Furthermore, pre-imprisonment factors like unemployment, lack of education, homelessness, a personal history of poverty, a history of drug use or abuse, and past mental illness significantly contribute to the development of common mental disorders among incarcerated people (32, 33). It is also well-recognized that understanding mental health problems depends on a person’s age (34). As a result, compared to older age groups, young prisoners have greater prevalence rates of mental health problems (34, 35).

If common mental disorders are not treated immediately, short-term and long-term physical, social, and vocational problems are inevitable (36, 37). The recurring nature of the problems, poor adherence, and treatment-seeking behavior all contribute to the long-term impact of common mental disorders (38). Common mental disorders have a negative influence on economic productivity, concomitant illnesses’ poor prognoses, disability, and health care costs (39). Mental health problems significantly affect the social, economic, educational, occupational, interpersonal, and physical condition of young prisoners (34, 35, 40).

Even though different primary studies were conducted in Ethiopia among prisoners to assess common mental disorders, their reports showed very discrepant and substantially inconsistent findings across the studies. Furthermore, to our knowledge, there is no previous systematic reviews and meta-analyses on the pooled prevalence and determinants of common mental disorders among prisoners in Ethiopia. Therefore, the main objective of this systematic review and meta-analysis was to identify the pooled prevalence of the common mental disorder among Ethiopian prisoners.

In this systematic review and meta-analysis, 3,585 prisoners were included. This study was conducted to estimate the pooled prevalence and associated factors of common mental disorders among Ethiopian prisoners. It is also the first systematic review and meta-analysis in Ethiopia among prisoners. The pooled prevalence of common mental disorders among included studies of Ethiopian prisoners was 62.29% with a 95% CI (50.94, 73.65). This finding is in line with different studies that were carried out in Kenya 63.2% (51), Zambia 63.10% (19), New Zealand 63.6% (52), Australia 63% (53), England 65.3% (54), and the United States 64% (25). The finding of this review is also consistent with the systematic review and meta-analysis were done in Africa among youth detained people with a pooled prevalence of 61% (55).

The Ethiopian pooled prevalence of common mental disorder was lower than other studies that were conducted in different countries like Nigeria 87.8% (56), Kenya 84% (57), Uganda 86% (4), Spain 84.4% (24), Germany75% (26), Canada 73% (27) and Brazil 68.9% (58). The possible reason for the discrepancy might be the difference in assessment tools. For example, the study conducted in Nigeria was measured by using General Health Questionnaire (GHQ-30), and the other study in Uganda was screened by using Mini International Neuropsychiatric Interview (MINI). The other difference might be the variation in sampled study participants. For instance, in Kenya, Brazil, and Germany, the studies were conducted among only female prisoners, who had a higher chance of vulnerability to common mental disorder (10).

The finding of the current systematic review and meta-analysis was higher than the results of other studies done in, Zambia 29.2% (59), Iran 43.4% (60), Cameron 34.8%, (61) United States 48% (62), and New South Wales, Australia 42.7% (63). The observed variation might be due to the fact that most other studies conducted in different countries had a single finding, whereas this study had a pooled prevalence from different studies. The additional discrepancy might be related to differences in the accessibility and delivery of mental health services in correctional settings, and variations in prison environments, such as work inside prison (4, 14). It could be also due to the difference in sample size and variation in socio-cultural among sampled study participants.

In addition to the pooled prevalence, in this review, determinants of common mental disorders were also determined among prisoners. The pooled effect of associated factors revealed that a history of mental illness, poor social support, and traumatic life events were significantly associated with common mental disorders among prisoners.

Accordingly, a history of mental illness was a significant predictor of common mental disorders among prisoners. This finding was supported by other studies conducted in Egypt (64). This might be due to the fact that Fear of social stigma and prejudice in prison, which inmates are preoccupied with and are likely to cause them distress, guilt about their illnesses, a lack of social support, and other stresses are all major sources of stress, and these may increase the likelihood of prisoners developing a common mental disorder (31). Another possible reason that may contribute to common mental disorder is that the stress of being incarcerated may make prisoners’ mental illnesses worse, and the impact of incarceration is so severe that it can lead to mental illness in those who are already vulnerable (14).

This systematic review and meta-analysis showed that prisoners with poor social support were more likely to develop a common mental disorder than prisoners who had good social support. This finding was consistent with other studies done in Netherlands (65), Iran (60), and Egypt (64). This could be because, a significant source of stress for those who are imprisoned includes having fewer close friends both inside and outside of prison, feeling less connected to family, and having fewer outside interactions through letters, phone calls, and visits, which contribute to the occurrence of prisoners common mental disorder (34). The other possible reason is also related, in addition to being the cause of mental illness, poor social support also affects the treatment outcomes of the disorder. Moreover, through positive assessment of the problems and a decrease in negative emotional responses, social support can improve the help-seeking and coping methods of prisoners (40).

This review also revealed that participants with traumatic life events were at higher risk of developing a common mental disorder than those without any traumatic life events. This finding was in line with the study conducted in the United States of America (66). This might be due to the fact that mental illness may manifest during imprisonment as a result of prison conditions such as social isolation, loss of connection with family and friends, restricted autonomy, lack of freedom, deprivation, and traumatic experiences (15, 26). The other additional explanation for this association is that the likelihood of developing a common mental disorder increases when a person experiences more stressful life events (20).

This systematic review and meta-analysis revealed that the pooled prevalence of common mental disorders among prisoners in Ethiopia was high. According to the findings of the subgroup analysis that was conducted using publication year, assessment tool, and regional state, there is a difference in the pooled prevalence of common mental disorders among prisoners. A history of mental illness, poor social support, and traumatic life events were recognized as significantly associated factors for the presence of common mental disorders. This indicated that prison administrators, the Ministry of Health, and policymakers should work collaboratively to increase and strengthen mental health facilities in correctional institutions, including early screening, detection, and interventions for mental health problems in prison. Moreover, it is necessary to provide some type of work inside prisons that may increase the unity among prisoners.

The original contributions presented in the study are included in the article/Supplementary material, further inquiries can be directed to the corresponding author.

SF conceptualized the study and was involved in the design, searching strategy, extraction of data, analysis and review of the article, interpretation, report, and manuscript writing. GMT, GT, and MM were involved in the data extraction. TT, GR, and FA made substantial contributions to the quality assessment of the included studies and the drafting of the manuscript. All authors contributed to the article and approved the submitted version.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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