Prevalence of Aggressive or Violent Behaviour in Thai Patients with Schizophrenia: a Cross-Sectional Study.
Patients with schizophrenia may experience distress, delusion, hallucination, and disorganised speech and behaviour. The rates of aggressive or violent behaviours and criminal offences have been reported to be higher among patients with schizophrenia than in the general population. (1-9) People with schizophrenia are 20-times more likely than the general population to commit homicide. (10) Approximately 1 in 600 patients with schizophrenia commit homicide prior to treatment, and the rate of homicide after antipsychotic treatment is about one in 10 000 patients per year. (11)
Aggressive or violent behaviour in patients with schizophrenia may be a response to psychotic delusions (especially paranoid or persecutory delusions), hallucinations, or misperceptions, and therefore a psychotic form of self-defense. (12) Factors associated with aggressive or violent behaviours in patients with schizophrenia include severity of psychotic symptoms, personality dimensions, substance abuse, and mentalising abilities, (13,14) whereas sociodemographic risk factors include economic deprivation (15) and social living status. (16)
There are few studies on factors associated with aggressive development, especially in Asian patients with schizophrenia. This study aimed to identify factors associated with aggressive or violent behaviour in Thai patients with schizophrenia.
The study was approved by the Ethics Committee of Faculty of Medicine, Chiang Mai University (EC/MEDCMU- PSY-2556-01814) and the Ethics Committee of Suan Prung Psychiatric Hospital (EC/SPPH-17-2556). Informed consent was obtained from each participant. This cross-sectional study was conducted in the largest mental health hospital in northern Thailand. All inpatients with schizophrenia aged [greater than or equal to]18 years admitted between January and November 2014 were screened for eligibility. Those who were diagnosed with any type of schizophrenia and received any treatment (antipsychotic drugs, electroconvulsive therapy, and/or supportive therapies) were included. Those who did not provide informed consent, refused to cooperate, or had other psychiatric disorders (schizoaffective disorder, bipolar disorder, major depressive disorder with psychotic feature, or delusional disorder) were excluded, as were those with severe medical conditions such as severe alcohol withdrawal syndrome or temporal lobe epilepsy.
Baseline interviews were conducted by a psychiatrist and psychiatric nurses. Demographic data such as sex, age, educational level, marital status, occupation, income, duration and type of schizophrenia, and treatment were collected. Patient characteristics were collected from the patients themselves, their relatives, and medical records. The diagnosis of schizophrenia was based on the Mini-International Neuropsychiatric Interview, Thai Version 5.0.0, a short structured diagnostic interview, and the DSM IV-TR, whereas the severity of comorbidities was measured using the Charlson comorbidity index. (17)
Violence includes threats and verbal aggression, aggression against property, self-harming behaviour, and physical aggression. (11,18) The psychosocial aspects potentially leading to aggressive or violent behaviour include relationships between patients and others (neighbours, co-workers, or family members), public reprimand or blame, forced treatment or medication, criticism from others (family members, relatives, friends, neighbours, or co-workers), and home and community environments. (11) Accessibility to weapons and toxic chemicals was evaluated; higher scores indicated higher risk of accessing weapons/toxic chemicals. History of being charged by the police with a criminal offence or convicted in a court of a criminal offence was collected.
In a previous study, the prevalence of aggressive or violent behaviour in patients with schizophrenia admitted to remand prison was 6.1% (166/2743). (3) The sample size required to make calculations with a 95% confidence interval was calculated as 88 patients; therefore, we planned to recruit 200 patients. To identify factors associated with aggressive or violent behaviour, violent and non-violent patients were compared using t-test or the Mann-Whitney U test (for continuous variables) and Fisher's exact test or [chi square] test (for categorical variables). A binary logistic regression model was applied to identify predictors of aggressive or violent behaviour. Significant independent variables (p < 0.05) and covariates (p < 0.20) at the bivariate level were included. All statistical analyses were carried out using SPSS (Windows version 22; IBM Corp, Armonk [NY], US)
Of the 230 patients with schizophrenia screened, 23 were excluded owing to incomplete data, and 207 (162 men and 45 women) with a mean age of 38.7 [+ or -] 10.3 years were included (Figure). Of the 207 patients, 67.6% were single; they had a mean of 7.7 [+ or -] 3.8 years of education; 36.7% were unemployed; and therefore, their income was low. 142 (68.6 %) had been diagnosed with paranoid schizophrenia and had the condition for a mean of 7.0 [+ or -] 7.7 years; 63 (30.4%) were treated with electroconvulsive therapy; and 35 (16.9%) had suicidal risk. Only 16 (7.7%) of patients had aggressive or violent behaviour, including verbal aggression (n = 7), physical aggression (n = 5), and aggression against property (n = 4). Nonetheless, only 2 (12.5%) of them had been charged by the police.
Violent and non-violent patients were comparable in terms of sex, age, years of schooling, marital status, occupation, personal and household income, and duration and type of schizophrenia. However, the weapon score was higher in violent patients (p < 0.05, Table 1). The binary logistic regression analysis showed that the weapon score was the only significant predictor of violence (adjusted [R.sup.2] = 0.172, standard error of the estimate = 0.034, Wald = 4.197, Table 2).
In the present study, only 16 (7.7%) patients with schizophrenia had aggressive or violent behaviour, mostly verbal aggression. Of them, only 2 (12.5%) were charged by the police for violent offenses. However, neither of those was convicted in court. The risk of aggressive or violent behaviour was significantly higher in patients with higher access to weapons.
The prevalence of violent offences is greater in patients with schizophrenia than in normal populations. A case-control study reported that the lifetime and 5-year prevalence of violent offence in patients with schizophrenia after the first admission was 8.2% and 3.0%, respectively, compared with 1.8% and 0.4% in controls. (1) Similarly, a meta-analysis found that 9.9% of patients with schizophrenia and other psychotic conditions were violent, compared with 1.6% of the general population. (10)
Substance use disorder is associated with aggressive or violent behaviour in patients with schizophrenia, (1,10,19-23) as are personality co-morbidities, particularly antisocial personality trait or disorder. (24,25) However, in Japanese patients with schizophrenia, violent behaviour is related to schizophrenic symptoms rather than antisocial traits or substance use disorder. (13) Similarly, the present study showed no association of substance use disorder or personality traits or disorders with schizophrenia in our patients. Rather, aggressive or violent behaviour may be caused by several factors before, during, and after periods of active illness and may be affected by cultural and racial diversity. (1,13)
The present study had some limitations. The sample size was small; a larger sample is needed to confirm these findings. All patients with schizophrenia were hospitalised, and their factors for developing aggressive or violent behaviour may differ from those of other non-hospitalised patients or patients with other psychotic conditions. Thus, the findings should only be generalised with caution. Cultural differences may influence the development of aggressive or violent behaviour in Thai patients with schizophrenia, and the findings may not be generalisable to other populations. Some patients who had committed acts of severe violence or homicide were imprisoned, and this may have also affected the prevalence of aggressive or violent behaviour that we found.
Thai patients with schizophrenia who had higher access to weapons were more likely to have aggressive or violent behaviour. Routine screening for access to weapons in clinical settings and adequate treatment of psychotic symptoms may reduce the incidence of aggressive or violent behaviour and violent offences.
This work was supported by the Faculty of Medicine, Chiang Mai University (046/2557) and Chiang Mai University (04/2562).
Narong Maneeton has received travel reimbursement from Lundbeck and Pfizer. Benchalak Maneeton has been an advisory board member of Pfizer and received honoraria and/or travel reimbursement from Lundbeck, Servier, and Pfizer. Natthanan Jaiyen, Pakapan Woottiluk, and Wajana Khemawichanurat report no conflicts of interest.
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Narong Maneeton, MD, FRCPsychT, Department of Psychiatry, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
Benchalak Maneeton, MD, FRCPsychT, Department of Psychiatry, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
Natthanan Jaiyen, MS (forensic), The Graduate School Chiang Mai University, Chiang Mai University, Chiang Mai, Thailand
Pakapan Woottiluk, APPMHN, MNS, RN, Psychiatric Nursing Division, Faculty of Nursing, Chiang Mai University, Chiang Mai, Thailand
Wajana Khemawichanurat, MD, FRCPsychT, Suan Prung Psychiatric Hospital, Chiang Mai, Thailand
Address for correspondence: Dr Benchalak Maneeton, Department of Psychiatry, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand. Email: email@example.com
Submitted: 20 December 2017; Accepted: 30 May 2018
Table 1. Demographic data of patients with schizophrenia. Factor Non-violent (n = 191) (*) Sex Male 151 (72.9) Female 40 (19.4) Age, y 38.4 [+ or -] 10.2 Years of schooling 7.7 [+ or -] 3.7 Educational level Uneducated 16 (7.7) 1-6 years 81 (39.1) 7-9 years 51 (24.6) 10-12 years 29 (14.0) [greater than or equal to]13 years 14 (6.8) Marital status Married 31 (15.0) Single 130 (62.8) Divorced/separated 25 (12.1) Widow 5 (2.4) Occupation Unemployed 68 (32.9) Employee 74 (35.7) Owner 11 (5.3) Government officer 1 (0.5) Agriculture 29 (14.0) Monk 7 (3.4) Student 1 (0.5) Annual personal 1643 [+ or -] 3092 income, US$ Annual household 3320 [+ or -] 4556 income, US$ Duration of 7.2 [+ or -] 7.7 schizophrenia, y Received 61 (29.5) electroconvulsive therapy Having suicidal risk 34 (16.4) Type of schizophrenia Paranoid 133 (64.3) Disorganized 2 (1.0) Catatonic 1 (0.5) Undifferentiated 54 (26.1) Unspecified 1 (0.5) Charlson comorbidity 0.1 [+ or -] 1.5 index score Nicotine use 71 (34.3) Alcohol use 17 (8.2) Amphetamine use 6 (2.9) Poor relationships with 46 (22.2) neighborhood(s) or workmate(s) Poor relationships with 39 (18.8) family member(s) Patients reprimanded or 37 (17.9) blamed in public Patients often subjected 52 (25.1) to forced treatment Patients subjected to 54 (26.1) forced medication Patients criticised by 39 (18.8) family member(s) or others Poor housing and home 31 (15.0) conditions Improper environmental 29 (14.0) conditions Weapon score 18.0 [+ or -] 8.7 Factor Violent p Value (n = 16) (*) Sex Male 12 (5.8) 0.751 Female 4 (1.9) Age, y 42.3 [+ or -] 11.2 0.201 Years of schooling 7.0 [+ or -] 4.7 0.571 Educational level 0.118 Uneducated 3 (1.4) 1-6 years 6 (2.9) 7-9 years 1 (0.5) 10-12 years 4 (1.9) [greater than or equal to]13 years 2 (1.0) Marital status 0.619 Married 3 (1.4) Single 10 (4.8) Divorced/separated 2 (1.0) Widow 1 (0.5) Occupation 0.885 Unemployed 8 (3.9) Employee 5 (2.4) Owner 1 (0.5) Government officer 0 (0) Agriculture 2 (1.0) Monk 0 (0) Student 0 (0) Annual personal 1616 [+ or -]1765 0.715 income, US$ Annual household 2443 [+ or -] 2873 0.314 income, US$ Duration of 5.3 [+ or -] 6.7 0.350 schizophrenia, y Received 2 (1.0) 0.156 electroconvulsive therapy Having suicidal risk 1 (0.5) 0.318 Type of schizophrenia 0.463 Paranoid 9 (4.3) Disorganized 0 (0) Catatonic 0 (0) Undifferentiated 7 (3.4) Unspecified 0 (0) Charlson comorbidity 0.3 [+ or -] 1.0 0.190 index score Nicotine use 5 (2.4) 0.637 Alcohol use 0 (0) 0.372 Amphetamine use 2 (1.0) 0.119 Poor relationships with 7 (3.4) 0.131 neighborhood(s) or workmate(s) Poor relationships with 2 (1.0) 0.744 family member(s) Patients reprimanded or 3 (1.4) 1.000 blamed in public Patients often subjected 7 (3.4) 0.162 to forced treatment Patients subjected to 7 (3.4) 0.252 forced medication Patients criticised by 5 (2.4) 0.341 family member(s) or others Poor housing and home 3 (1.4) 0.731 conditions Improper environmental 4 (1.9) 0.293 conditions Weapon score 23.6 [+ or -] 8.1 0.021 (*) Data are presented as mean [+ or -] standard deviation or No. (%) of participants. Table 2. Binary logistic regression analysis of predictors for aggression/violence in patients with schizophrenia. Co-variable [beta] Standard Wald error Uneducated 0.761 0.745 1.044 Electroconvulsive therapy -1.002 0.804 1.554 Charlson comorbidity index 0.078 0.139 0.316 Amphetamine use 1.394 0.964 2.093 Poor relationships 0.980 0.613 2.553 Patients with forced treatment 0.486 0.599 0.659 Weapon score 0.070 0.034 4.197 Constant -4.451 0.923 23.258 Co-variable Odds ratio (95% p Value confidence interval) Uneducated 2.140 (0.497-9.211) 0.307 Electroconvulsive therapy 0.367 (0.076-1.774) 0.213 Charlson comorbidity index 1.081 (0.824-1.419) 0.574 Amphetamine use 4.032 (0.610-26.670) 0.148 Poor relationships 2.664 (0.801-8.858) 0.110 Patients with forced treatment 1.626 (0.503-5.256) 0.417 Weapon score 1.073 (1.003-1.148) 0.041 Constant 0.012 0.000
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|Title Annotation:||Original Article|
|Author:||Maneeton, Narong; Maneeton, Benchalak; Jaiyen, Natthanan; Woottiluk, Pakapan; Khemawichanurat, Wajan|
|Publication:||East Asian Archives of Psychiatry|
|Article Type:||Clinical report|
|Date:||Sep 1, 2019|
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