Mental health status among male and female methamphetamine-dependent inmates in Japan

Background Although the prevalence of drug addiction in Japan is lower than that of in European and/or American countries, the number of methamphetamine-related arrests in this decade has exceeded 10,000 every year, with 66.2% of the arrests made in 2017 being of re-offenders. This study was performed to assess the mental health status among prison inmates whose sentences were related to methamphetamine use. Methods Face-to-face individual interviews using a questionnaire including self-rated health questions (answered on a 4-point Likert scale) and the Kessler 6-item psychological distress scale (K6, range: 0-24) was established by the authors and conducted with 30 methamphetamine-dependent inmates (15 male and 15 female inmates) in Japan. Results The age of inmates ranged from the 20s to the 70s. The median time served in adulthood was 5 (range: 2 - 12) among male inmates, and 4.5 (range: 2 - 12) among female inmates (Mann-Whitney U test, P = 0.202). The median K6 scores were 4 (0-8) for the male inmates and 6 (1-17) for the female inmates (Mann-Whitney U test, P = 0.074). The cut-off point for K6 exhibited variation, and the authors considered a participant psychologically distressed if K6 was 10 or higher. Six (40.0%) female inmates were found to be psychologically distressed, which was a higher proportion than among the male inmates (0.0%) (Fisher's exact test, P = 0.017). Regarding self-rated health, 13 (86.7%) of both male and female inmates reported being in “very good/good health” (Cochran-Armitage Test, P ¬= 1.000). There was no statistical correlation between the K6 scores and the self-rated health scores among the male inmates (ρ = 0.148, P = 0.599) or the female inmates (ρ = -0.499, P = 0.058). Conclusions Although the interviewees were not representative samples, the male inmates demonstrated better mental health status than the female inmates did; however, there was no difference in self-rated health between the two genders. Key messages The male inmates demonstrated better mental health status than the female inmates did; however, there was no difference in self-rated health between the two genders. Gender differences in mental health status among inmates, should be considered when a drug addiction recovery program is implemented to ensure the successful prevention of relapse.