5. Discussion
In this study the prevalence of antisocial personality disorder was assessed by using psychopathic check list revised. The independent factors associated with antisocial personality disorder were age (18-27), single marital status, prior conviction, tobacco ever use, and monthly income less than 1557 Birr.
The prevalence of antisocial personality disorder among Mekelle correctional center prisoners was found to be 31 % with confident interval (26.5-35.6). It is alien with a study conducted in England and Wales by using schedules for clinical interview in neuropsychiatry and psychopathy checklist-revised(31%)(27),UK by using IPDE-SQ(25.8%)(23),Iraq by using PCL-R (31%)(32),Sweden by using PCL-R(31%)(26) and USA by using MINI(35.3%) (31).
In this study the finding was lower as compare to the study conducted in USA by using SIPD-IV(57%) (22), UK by using PCL-R (68%) (28) , South Africa by using MINI (46.1%)(4),Nigeria by using Antisocial Personality Disorder Self- Test (47%) (33) among prisoners. The difference may be due to socio-cultural, environmental, sample size and using of different tool and cut points to determine the prevalence of antisocial personality disorder.
However the prevalence was higher as compare to the studies conducted in Germany by using PCL-R(17%)(21). The difference with this study may be due to the study from Germany includes only female inmates but in this study majority of the participant were men. The prevalence is also higher than the study done in Italy by using MINI (20%)(25), the difference may be due to using different tool and the research from Italy was done in community sample which ASPD is lower than from prison samples.
The prevalence of ASPD in this study was also higher than the research conducted in Egypt (12.3%) (30). The difference may be due to difference in environment, socio-cultural factors and using of different tool. In this study PCL-R was used to decide the ASPD but the study from Egypt used structured Clinical Interview for the DSM-IV Axis I and Axis II disorders
The prevalence of antisocial personality disorder was found to be higher among the age group of 18-37 as compare to those who are in the age group of >47 years. The finding is in line with the study conducted in UK ASPD is high among the young age(19).The high prevalence of ASPD among the age group may be due to the age is in transition between adolescence and adult age and those with conduct disorder in adolescent age my directly changed to antisocial personality disorder in the adult age. In other way it may be due to the yang age overt behavior such as criminality, substance use and aggressiveness increased in this age.
In this study single marital status was significantly associated with ASPD. A research done in Zambia came up with the same report(36). The possible justification for the high prevalence of ASPD among single participants may be due to that individuals with ASPD have difficulty to form and maintain intimate relationship because of their odd behaviors.
Tobacco ever was associated with antisocial personality disorder. Participants who had tobacco ever use were almost three times more likely to have ASPD as compare to those prisoners who had no tobacco ever use. This is supported by two researches conducted in the USA indicates that most people from the community sample with ASPD are chronic cigarette smokers and other substance users(31,38). It is also support by a research conducted in Turkey(39) This may be due to most of the participants were young adult age who have high probability to test substance and being against the norm of the community .
This study revealed that there was significant association between prior conviction and ASPD. The study conducted in Egypt on prisoners came up with similar finding (30) it is also supported by a research from South Africa (4). The high prevalence of ASPD among prisoners who had prior conviction may be due to repeated imprisonment of individuals with antisocial behavior such as destroying property, harassing others, stealing, or charging illegal occupations and other odd behaviors . Individuals with ASPD fail to conform to societal rules, persistent pattern of disrespect for, and violation of, the rights of others may be possible justification.
Having low monthly income was also had significant association with ASPD. The odds of anti-social personality disorder among those who had monthly income less than 1557 birr per month were four times higher as compare to those who had monthly income above 1557 birr per month).According to DSM-5 ASPD is high among those who have poor economic status(9). Having significant periods of unemployment despite available job opportunities and unable to work for long time due to their antisocial behavior may be possible reasons for low economic status.
Variables which had significant association with antisocial personality disorder in other study but not significant associated with ASPD in this study are being male, having history of psychiatric illness and poor educational status. The difference may be due to variation in culture, sample size, economical status of the participants.