Table 1 Sample characteristic of the N = 259 subjects

Age (yrs)*

35.5 (11.2)

29.6 (7.2)

W = 11070.5; p < .001

Gender (female %)

21 (16)

10 (8)

p = .055

Home country national (%)

66 (52)

85 (70)

p = .003

Intelligence classification (%)

   Inferior

12 (9)

3 (2)

χ² = 7.7, df = 4; p = .100

   Low

11 (8)

8 (6)

   Moderate

90 (69)

104 (82)

   High

11 (8)

8 (6)

   Superior

6 (5)

4 (3)

Mental and behavioral disorders according to ICD-10

   Organic disease (%)

5 (4)

2 (2)

p = .447

   Substance abuse (%)

39 (30)

87 (68)

p < .001

   Schizophrenic disorders (%)

6 (5)

5 (4)

p = 1.00

   Affective disorders (%)

7 (5)

3 (2)

p = .334

   Somatoform disorders (%)

16 (12)

6 (5)

p = .043

   Personality disorders (%)

58 (44)

74 (58)

p = .035

   Mental retardation (%)

3 (2)

1 (1)

p = .622

   Developmental disorder (%)

1 (1)

0 (0)

p =1.00

   Disorders with onset in childhood and adolescence (%)

0 (0)

4 (3)

p = .058

Index offences

   Danger to public safety (%)

3 (2)

2 (2)

p = 1.00

   Violation of narcotics law (%)

7 (5)

18 (14)

p = .021

   Illegal restraints (%)

7 (5)

7 (5)

p = 1.00

   Offence against life and limb other than homicide (%)

2 (2)

0 (0)

p = .498

   Miscellaneous offences (%)

2 (2)

0 (0)

p = .498

   Assault (%)

6 (5)

18 (14)

p = .010

   Homicide (%)

67 (51)

21 (16)

p < .001

   Property crimes (%)

9 (7)

35 (27)

p < .001

   Robbery (%)

2 (2)

12 (9)

p = .006

   Sex offence (%)

26 (20)

15 (12)

p = .089

Diversity of criminal history*

0 (1)

2 (3)

W = 5102.5; p < .001

Number of prior convictions*

0 (1)

3 (3)

W = 2411; p < .001

Number of prior offences*

0 (4)

9 (15)

W = 2636; p < .001

Duration of prior imprisonment (%)

   0 yrs

102 (78)

57 (45)

χ² = 32.3, df = 2; p < .001

   < 1 yrs

11 (8)

39 (30)

   >1 yrs

18 (14)

32 (25)