According to the World Health Organization (WHO) global burden of diseases 2010 report, mental and substance use disorders (SUD), are the leading cause of years of life lost due to disability . Mental and SUD are among the top 10 causes of disability adjusted life years (DALYs) with 184 million DALYs; illicit drug use accounts for 10.9% of all DALYs . According to a report by Balint et al (2009), an estimated 5–10 million people chew khat daily worldwide .
It is generally believed that the worldwide prison population is increasing in a rate faster than the population growth. Over the last 15 years the world population has increased by over 20%, whereas the world prison population increased by 25–30% . As of the beginning of October 2013, more than 11 million people in the world were either in prison, in pre-trial, or in administrative detention. The same report showed that, in 2013, in Ethiopia there were about 112,361 prisoners .
Previous studies showed the positive association between crime and substance use [4–7]. In one of those studies , more than half of prisoners due to murder were abusing drug when they committed the crime; almost 50% of them were intoxicated at the time of committing the murder. This is supported through longitudinal data in the United States . In addition, illicit drug use is associated with physical intimate partner violence . A literature review by Poldrugo et al (1998) found strong relationship between substance use and criminal behavior . In support of this, a study from Jimma prison, Ethiopia, reported that 10% of homicide offenders admitted that the homicide happened under the influence of substance . People use substance to increase their confidence in committing crime, and this makes the condition more serious .
In comparison to studies in the general population, drug use was reported to be eight times more common among prisoners . For any substance the prevalence ranges as low as 20.1% to as high as 95.5%. For drug use disorder (DUD), a prevalence ranging from 11.0–70.0% was reported [11–22]. Conversely, the prevalence of SUD before imprisonment is higher than both from use in prison and use in the general population implying that there is a relationship between crime and using substance. Studies have shown prevalence rate ranging from 50–88% for general substance, and 25%-73.8% for drug, before imprisonment [8, 9, 23–38].
A more recent systematic review of about 24 studies from 10 different countries reported a 30% pooled prevalence of DUD, which ranged from 10–61% among male prisoners . Another systematic review reported a prevalence rate of drug dependence ranging from 10%-48% among male prisoners .
Overall, studies on the prevalence of SUD among prisoners in low and middle-income countries are very few. A systematic review of studies conducted worldwide by Fazel and colleagues (2017) , was able to find only two studies from low and middle-income countries. These studies reported a prevalence of 30% and 56% for DUD . In Africa, studies which assessed the prevalence and associated factors of SUD among prisoners are lacking. We found a study from Kenya, which reported that 9.4% of prisoners use amphetamine, a substance having similar effect with khat, and 66.1% of prisoners had life time history of using substance .
Several factors were reported to be associated with substance use before imprisonment. These include younger age at the time of committing the offence, male sex, urban residence, higher educational status, presence of physical health problem, previous history of committing crime (property theft, rape, or fraud), seriousness of the crime, committing repeated offence, and presence of depression before imprisonment [9, 32, 41–44].
In Ethiopia different population-based studies showed that Khat chewing is prevalent [45–48]. On top of this, a case report from Amanuel Mental Specialized Hospital, Addis Ababa, Ethiopia, showed that heavy Khat chewing may have a potential to induce major mental disorders (such as psychosis), and aggravate criminality . However, we only found two studies conducted among prison population in Ethiopia [8, 50]. The studies reported 44% of history of Khat use among homicide offenders , and 60% prevalence of Kat chewing among the general prisoners . However, both of those studies were conducted in the same study site (Jimma town), which is a khat cultivating area unlike our study site (Debre Berhan town) where khat growing is not common. Therefore, this study aimed to assess the prevalence and associated factors of problematic khat use (PKU) among prisoners of Debre Berhan prison before imprisonment.