Table 1 Distribution of patients and victims’ characteristics among forensic patients with weapon use at their index offense

Patients’ characteristics

Age (years)

Age at the index offense

Mean 34.27 (Standard Deviation = 12.20)

The mean age of weapon use is equal to that who did not use weapons

34.89 (11.67)

33.61 (12.73)

1.50 (0.134)

Gender (as reported by patient)

Male

701 (85.59)

Weapon use during the index offence and gender are independent

361 (51.50)

340 (48.50)

0.30 (0,582)

Female

126 (14.53)

64 (54.24)

54 (45.76)

Previous hospitalization for a psychiatric condition

No

121 (14.85)

Weapon use during the index offence and Previous hospitalization for a psychiatric condition are independent

41 (33.88)

80 (66.12)

18.48 (< 0.001)

Yes

694 (85.15)

382 (55.04)

312 (44.96)

Primary psychiatric diagnosis

Psychotic disorder

680 (83.03)

Weapon use during the index offence and primary psychiatric diagnosis are independent

345 (50.74)

335 (49.26)

11.63 (0.020)

Mood disorder

52 (6.35)

33 (63.46)

19 (36.54)

Neurodevelopmental disorder

25 (3.05)

11 (44.00)

14 (56.00)

Personality disorder

29 (3.54)

22 (75.86)

7 (24.14)

Others

33 (4.03)

14 (42.42)

19 (57.58)

Intoxication at the time of the index offense

No

710 (86.69)

Weapon use during the index offence and intoxication at index offence are independent

373 (52.54)

337 (47.46)

7.72 (0.172)

Drugs

41 (5.01)

16 (39.02)

25 (60.98)

Alcohol

42 (5.13)

24 (57.14)

18 (42.86)

Yes (not specified)

5 (0.61)

1 (20.00)

4 (80.00)

Both (alcohol and drugs)

7 (0.85)

2 (28.57)

5 (71.43)

Unknown

14 (1.71)

9 (64.29)

5 (35.71)

Victims’ characteristics

Victim gender

Male

394 (48.11)

Weapon use during the index offence and victim’s gender are independent

179 (45.43)

215 (54.57)

20.11 (< 0.001)

Female

358 (43.71)

197 (55.03)

161 (44.97)

Unknown

67 (8.18)

49 (73.13)

18 (26.87)

Victim age

Age in years at the time of the offence (717 victims had the age missing from the records)

Median = 33.5 and Interquartile range = 12–61

The median age between those who used weapon during the index offence use and those who did not are equal

15 (8–54)

49 (18–64)

1751.5 (0.014)

Victims’ relationship with the patient

Stanger – adult

236 (28.82)

Weapon use during the index offence and victim’s relationship are independent

132 (55.93)

104 (44.07)

96.75 (< 0.001)

Stranger – child

18 (2.20)

13 (72.22)

5 (27.78)

Acquaintance – adult

115 (14.04)

45 (39.13)

70 (60.87)

Acquaintance – child

3 (0.37)

2 (66.67)

1 (33.33)

Friend

16 (1.95)

6 (37.50)

10 (62.50)

Parent

113 (13.80)

39 (34.51)

74 (65.49)

Son/daughter

20 (2.44)

12 (60.00)

8 (40.00)

Sibling

31 (3.79)

10 (32.26)

21 (67.74)

Lover/partner/spouse

43 (5.25)

15 (34.88)

28 (65.12)

Other family members

24 (2.93)

4 (16.67)

20 (83.33)

Law enforcement professionals

83 (10.13)

61 (73.49)

22 (26.51)

Healthcare/support staff

66 (8.06)

55 (83.33)

11 (16.67)

Co-habitant/co-patient

23 (2.81)

13 (56.52)

10 (43.48)

Others

10 (1.22)

4 (40.00)

6 (60.00)

Unknown

18 (2.20)

14 (77.78)

4 (22.22)