Background

The relationship between mental illness and violent crime is complex because of the involvement of many other confounding risk factors. In the present study, we analysed psychiatric and neurological disorders in relation to the risk of convictions for violent crime, taking into account early behavioural and socio-economic risk factors.

Methods

The study population consisted of 49,398 Swedish men, who were thoroughly assessed at conscription for compulsory military service during the years 1969–1970 and followed in national crime registers up to 2006. Five diagnostic groups were analysed: anxiety-depression/neuroses, personality disorders, substance-related disorders, mental retardation and neurological conditions. In addition, eight confounders measured at conscription and based on the literature on violence risk assessment, were added to the analyses. The relative risks of convictions for violent crime during 35 years after conscription were examined in relation to psychiatric diagnoses and other risk factors at conscription, as measured by odds ratios (ORs) and confidence intervals (CIs) from bivariate and multivariate logistic regression analyses.

Results

In the bivariate analyses there was a significant association between receiving a psychiatric diagnosis at conscription and a future conviction for violent crime (OR = 3.83, 95 % CI = 3.47–4.22), whereas no significant association between neurological conditions and future violent crime (OR = 1.03, 95 % CI = 0.48–2.21) was found. In the fully adjusted multivariate logistic regression model, mental retardation had the strongest association with future violent crime (OR = 3.60, 95 % CI = 2.73–4.75), followed by substance-related disorders (OR = 2.81, 95 % CI = 2.18–3.62), personality disorders (OR = 2.66, 95 % CI = 2.21–3.19) and anxiety-depression (OR = 1.29, 95 % CI = 1.07–1.55). Among the other risk factors, early behavioural problem had the strongest association with convictions for violent crime.

Conclusions

Mental retardation, substance-related disorders, personality disorders and early behavioural problems are important predictors of convictions for violent crime in men.

Table 1

Adolescent risk factors for future convictions for violent crime

Variables	Violent crime
Variables	OR (95 % CI)
Poor economic conditions in family (very or rather poor vs. average, rather or very good)	1.42 (1.24–1.64)
Divorced parents (yes vs. no)	2.87 (2.60–3.18)
Corporal punishment in upbringing (often or sometimes vs. seldom or never)	1.96 (1.76–2.18)
Easily angry (often vs. sometimes, seldom or never)	3.13 (2.80–3.51)
Sleep disturbance (often vs. sometimes, seldom or never)	1.76 (1.52–2.04)
Lowered marks due to misconduct at school (several times or once vs. never)	3.92 (3.61–4.27)
Contact with the police or child welfare committee (several times or sometimes vs. never)	5.32 (4.87–5.82)
Arrested by police for drunkenness (several times, twice or once vs. never)	5.91 (5.36–6.50)

Table 2

Multivariate analyses for future convictions for violent crime in Models I–IV

	Model I	Model II	Model III	Model IV
	OR (95 % CI)	OR (95 % CI)	OR (95 % CI)	OR (95 % CI)
Anxiety-depression (yes vs. no)	1.99 (1.69–2.34)	1.79 (1.51–2.12)	1.63 (1.37–1.94)	1.29 (1.07–1.55)
Personality disorder (yes vs. no)	5.36 (4.60–6.25)	4.90 (4.16–5.76)	4.29 (3.62–5.08)	2.66 (2.21–3.19)
Substance-related disorder (yes vs. no)	10.08 (8.18–12.42)	8.18 (6.53–10.26)	7.55 (5.98–9.54)	2.81 (2.18–3.62)
Mental retardation (yes vs. no)	5.65 (4.50–7.09)	4.95 (3.87–6.33)	4.39 (3.40–5.67)	3.60 (2.73–4.75)
Poor economic conditions in family		1.00 (0.86–1.17)	0.98 (0.84–1.15)	1.00 (0.85–1.18)
(very or rather poor vs. average, rather or very good)		1.00 (0.86–1.17)	0.98 (0.84–1.15)	1.00 (0.85–1.18)
Divorced parents		2.32 (2.08–2.59)	2.30 (2.06–2.58)	1.68 (1.49–1.90)
(yes vs. no)		2.32 (2.08–2.59)	2.30 (2.06–2.58)	1.68 (1.49–1.90)
Corporal punishment in upbringing		1.61 (1.43–1.80)	1.52 (1.35–1.71)	1.29 (1.14–1.46)
(often or sometimes vs. seldom or never)		1.61 (1.43–1.80)	1.52 (1.35–1.71)	1.29 (1.14–1.46)
Easily angry (often vs. sometimes, seldom or never)			2.15 (1.89–2.45)	1.72 (1.50–1.98)
Sleep disturbance (often vs. sometimes, seldom or never)			0.93 (0.78–1.11)	0.84 (0.70–1.01)
Lowered marks due to misconduct at school (several times or once vs. never)				2.11 (1.91–2.34)
Contact with the police or child welfare committee (several times or sometimes vs. never)				2.67 (2.38–2.99)
Arrested by police for drunkenness (several times, twice or once vs. never)				2.06 (1.82–2.32)

Model 1. Model fit: Chi-square = 798.98, DF = 4, p < 0.0001; p-values of all included predictors < 0.0001

Model 2. Model fit: Chi-square =1032.38, DF = 7, p < 0.0001; p-values of all included predictors except poor economic conditions in family (p = 1.00) were significant, p < 0.0001

Model 3. Model fit: Chi-square = 1128.36, DF = 9, p < 0.0001; p-values of all included predictors except poor economic conditions in family (p = 0.80) and sleep disturbance (p = 0.44) were significant, p < 0.0001

Model 4. Model fit: Chi-square = 2231.10, DF = 12, p < 0.0001; p-values of all included predictors except poor economic conditions in family (p = 0.98) and sleep disturbance (p = 0.058) were significant: Anxiety-depression, p = 0.0074, all other p values < 0.0001

Full article at: http://goo.gl/y7AOGu

By: Tomas Moberg, corresponding author