Int. J. Environ. Res. Public Health 2009, 6 3063 methamphetamine by injection (80.8%), whereas a minority of patients used the injection route (41.8%). No participants in either group reported cocaine or opiate abuse. Table 4. Lifetime prevalence of substance use/abuse lasting more than 1 year. Substance Inmates (n = 52) Patients (n = 55) p values Methamphetamine abuse, n (%) 50 (96.2) 52 (94.5) n.s. Duration (years), M (SD) 4.8 (0.63) 8.2 (0.91) p = 0.001** Drug use by injection, n (%) 42 (80.8) 23 (41.8) p < 0.001*** Alcohol use, n (%) 40 (76.9) 41 (74.5) n.s. Duration (years), M (SD) 17.6 (1.39) 15.3 (1.48) p = 0.0116* Cannabis abuse, n (%) 6 (11.5) 23 (41.8) p < 0.001*** Duration (years), M (SD) 6.5 (3.55) 7.0 (1.28) n.s. aMbeutshey,lnen(e%d)ioxymethamphetamine 0 (0) 6 (10.9) p = 0.014* Duration (years), M (SD) 0 (0) 2.3 (0.56) p = 0.015* Inhalant abuse, n (%) 32 (61.5) 18 (32.7) p = 0.003** Duration (years), M (SD) 4.1 (0.56) 3.6 (0.65) n.s. n, number of participants; M, mean; SD, standard deviation; n.s., not significant Note: The Mann-Whitney Wilcoxon test was used for the statistical comparison with continuous values. The 2 test was used for the other categories. *p < 0.05, **p < 0.01, ***p < 0.001 3.4. Psychiatric Symptoms The number and percentage of participants who reported psychiatric symptoms in their lifetime are shown in Table 5. The inmates experienced less major depression, anxiety and tension, and hallucinations in their lifetime than patients. Additionally, no significant associations were found between the duration of methamphetamine abuse and these psychiatric symptoms using Spearman’s rank correlation coefficient analysis in both groups (rs = −0.006–0.186, n.s.). Moreover, inmates received less prescribed medication in their lifetime than patients. Although these psychiatric symptoms were not common among inmates, the lifetime prevalence of suicidal behavior and trouble controlling violence was not significantly lower than in patients. Table 5. Lifetime prevalence of psychiatric symptoms. Symptoms Serious depression (a) Serious anxiety or tension (a) Hallucinations (a) Inmates (n = 52) n (%) 9 (17.3) 14 (26.9) 3 (5.8) Patients (n = 55) n (%) 24 (43.6) 25 (45.5) 22 (40.0) p values p = 0.003** p = 0.047* p < 0.001***