Co-Morbid Physical Illness among Depressed Prisoners in a Nigerian Prison Population

Depression frequently co-occurs with physical illness such as cardiovascular illness, infectious diseases or cancer which leads to disproportionally increased disability especially among prisoners [1]. The two conditions have separate but additive effects on well-being of sufferers as they may cause poor adherence to treatment. For instance depression and cardiovascular disorders in combination can result in twice the reduction of social interaction than either of the conditions alone. According to Goldberg, chronic physical illness and depression have a reciprocal relationship. Goldberg reported that many chronic physical illnesses not only cause elevated rates of depression, but depression has been reported to antedate chronic physical illnesses [2]. Hence, depression among physically ill individuals is more likely to be missed by professionals than if it occurs alone [2]. Several studies around the world have reported the cooccurrence of psychiatric disorders generally and co-morbid physical illnesses in the prison population. A study of 557 adult prisoners found affective disorder to be positively related to respiratory, gastrointestinal and musculoskeletal system disorder [3]. In the United Kingdom a study among geriatric inmates found depression among half of the studied subjects with physical illness common among them [4]. A similar study among geriatric inmates found a strong relationship between unmet physical health needs and clinical symptoms of depression in the sample studied [5]. In Nigeria Agbahowe studied convicted inmates and found depression in 4% with gastrointestinal system disorder the commonest physical illness [6]. Studies in Calabar and Jos Nigeria among prisoners reported significant relationships between psychiatric morbidity and Abstract


Introduction
Depression frequently co-occurs with physical illness such as cardiovascular illness, infectious diseases or cancer which leads to disproportionally increased disability especially among prisoners [1]. The two conditions have separate but additive effects on well-being of sufferers as they may cause poor adherence to treatment. For instance depression and cardiovascular disorders in combination can result in twice the reduction of social interaction than either of the conditions alone. According to Goldberg, chronic physical illness and depression have a reciprocal relationship. Goldberg reported that many chronic physical illnesses not only cause elevated rates of depression, but depression has been reported to antedate chronic physical illnesses [2]. Hence, depression among physically ill individuals is more likely to be missed by professionals than if it occurs alone [2].
Several studies around the world have reported the cooccurrence of psychiatric disorders generally and co-morbid physical illnesses in the prison population. A study of 557 adult prisoners found affective disorder to be positively related to respiratory, gastrointestinal and musculoskeletal system disorder [3]. In the United Kingdom a study among geriatric inmates found depression among half of the studied subjects with physical illness common among them [4]. A similar study among geriatric inmates found a strong relationship between unmet physical health needs and clinical symptoms of depression in the sample studied [5]. In Nigeria Agbahowe studied convicted inmates and found depression in 4% with gastrointestinal system disorder the commonest physical illness [6]. Studies in Calabar and Jos Nigeria among prisoners reported significant relationships between psychiatric morbidity and comorbid physical illness [7,8]. However, these studies were not specific to depression. A study also in Nigeria showed that untreated depression among prisoners is increasingly becoming a public health problem and therefore intervention is necessary even though the study did not relate depression to physical comorbidity [9].
This study aimed at determining the relationship between depression and comorbid physical illness which to the knowledge of the authors is the first of such studies from a Nigerian prison population.

Materials and Method Participants
The study was part of a comprehensive prospective crosssectional study conducted at the Jos maximum security prison, Plateau state Nigeria from June 2015 to November 2015. Six hundred and fifty five adult male inmates (awaiting trial and convicted) were involved in the study. The study was approved by the Jos University Teaching Hospital (JUTH) Human and Research Ethics Committee and is consistent with the Declaration of Helsinki (JUTH/DCS/ADM/127/XIX/2758). All participants provided informed signed or thumb printed consent before participating in the study. Data were collected by the researchers who are fluent in the two major languages spoken by the participants (English, Hausa or both languages). Participants who were literate enough filled out their questionnaires. The questionnaires were translated for participants who were unable to speak English. This was done on every working day until all the eligible inmates were interviewed. A total of 655 participants were interviewed and had their complete demographics, clinical and forensic data entered for analysis. The data was collected in two stages as follows:

Sociodemographic, Forensic Data and Screening for Depression
In the first stage, each consecutive participant was administered the socio-demographic (for data such as age, educational status etc.), forensic data questionnaire (prison status, type of offence among others) and the General Health Questionnaire-28 (GHQ-28) screening instrument. The GHQ-28 is a self -administered screening instrument which was given to all the participants. It was designed to cover four identifiable areas of distress: depression, anxiety, social impairment and hypochondrias is. It is used as a screening instrument for mental disorders following which the diagnosis is confirmed with a more specific instrument.

Diagnosis of Depression
In the second stage, participants with GHQ-28 score of four (4) and above were administered the Depressive module of Composite International Diagnostic Interview (CIDI) which took the form of a clinical interview. Thus, all participants with GHQ-28 score of at least 4 were therefore administered the CIDI to assess for depression. Those who fulfilled the ICD-10 diagnostic criteria were assigned a diagnosis of depressive disorder.

Physical illness
History and detailed physical examination was carried out on inmates. Inmates with evidence of physical co-morbid illnesses were classified under the broad categories of which ICD 10. Assessment was carried out by the researchers three of Which are consultant psychiatrist.

Statistical Analysis
The Statistical Package for Social Sciences (SPSS) version 20.0 software package was used to analyse the data. Nonparametric statistic test was Used to analyse the data because it was categorical. Simple descriptive analysis was use to summarize sociodemographic variable using frequency count and percentage. The chi-square test was used to investigate the relationship between depression and comorbid physical illness and the value of p<0.05 was considered statistically significant.

Results
All the subjects studied were male, with 52% within the age group of 25-34years and a mean age of 32.1±10.6 years. Two hundred and three (55.5%) were single, 33.9% married while 0.5% were widowed. Almost half of the studied subjects (46%) had some form of secondary with 23% having no formal education in Table 1. More than half (56.8%) of the studied subjects were unemployed before incarceration, while 16.4% were students in Table 1. Depression was found in 120 (18.3%) of the participants in Table 2. Thirty-six (30%) of the depressed participants had comorbid physical illness with cardiovascular disease as the commonest physical comorbidity found in 9 (25%) of the participants in Table 3. A statistically significant relationship was established between depression and physical comorbidity in the studies (p = 0.001) (0R=3.16) participants in Table 4.  Prevalence of depression was found among120 (18.3%) participants.

Discussion
In this study depression was found in less than a quarter (18.3%) of the participants studied. This is slightly above the values gotten in most studies done in prisons (4 -17.9%) [10][11][12][13]. The variation might be because of the different types of questionnaires used in the studies. Also rates seem to be underestimated if interview is administered by lay investigators. Most of the subjects were either unemployed, retired or apprentice before incarceration and poverty has been found as a major risk factor for depression [14].
Findings from recent studies indicate that the prevalence of mental illness is generally higher in prisons than in the community and comorbidity is common [15]. The study found 18.3% of the depressed prisoners had comorbid physical illnesses with strong association found between depression and comorbid physical illnesses (p <0.001) (OR=.3.16) Patients with physical illnesses especially chronic ones have a high prevalence of depression due to the decreased ability to function as seen in many chronic illnesses [16]. Pain is a symptom seen in many chronic illnesses. Pain and depression have been found to share common biological and neurotransmitter pathways hence the strong association [17]. About 50-54% of patients with chronic pain have depression [18]. Depression reduces pain threshold, increases pain ratings, leading to significant autonomic hyperactivity, increased muscle tension, insomnia and anxiety [18]. The presence of pain however negatively affects the recognition and treatment of depression [17]. It is therefore important that individuals with chronic medical conditions in the prisons are regularly assessed for depression because the presence of this comorbidity has been found to be linked with 50% increase in medical expenses for chronic medical illness, and worse treatment outcomes have also been found in these individuals [16,17].
Among depressed patients in the study, the most frequent comorbid physical illness was due to diseases of the cardiovascular system, respiratory system, infectious diseases, and endocrine system. This is not surprising as this fact has been established in previous studies. For example depression has been found to be a strong independent risk factor for myocardial infarction, fatal and non-fatal cardiac events and treatment of depression has been found to improve compliance with cardiac regiments and improved global functioning in such patients [19]. Also the odd of developing depression is two times greater in diabetics than non-diabetic patients [20]. Patients with depression and diabetes have a higher rate of insulin resistance, obesity, sexual dysfunction and peripheral neuropathy and treatment of depression is associated with improved glycaemic control [19][20].
Recommendation prison inmates for early detection and treatment of psychiatric disorders especially depression among physically ill inmates to enhance well-being of affected prisoners. Training and retraining of prison clinical staff for early detection of depression and other psychiatric disorders among prisoner should be fostered.

Conclusion
In conclusion, our study found depression to be positively associated with physical illness in adult male inmates. The findings in this study support the fact that depression is found as a comorbidity with other physical illnesses in the prison. Since the presence of depression can affect the course and outcome of physical illness, it is therefore important that the condition be recognized and managed so as to improve overall functioning and general health of the patients. Because recognition of depression in patients with physical health problems might be difficult it is important that the prison services work in close association with psychiatrists. This will in the long run be more cost effective in managing the overall health of the inmates thus improving their functioning and quality of life.