East Midlands Centre for Forensic Mental Health, Leicester
Moorside, Trafford General Hospital, Manchester
Division of Psychiatry, University of Nottingham, Nottingham
Division of Psychiatry, University of Bristol, Bristol
Division of Psychiatry, University of Nottingham, Nottingham, UK
Correspondence: Dr John Milton, East Midlands Centre for Forensic Mental Health, Arnold Lodge, Cordelia Close, Leicester LE5 OLE, UK. Tel: 0116 225 6060; Fax: 0116 225 6061; e-mail: John.Milton{at}arnoldl.cnhc-tr.trent.nhs.uk
Declaration of interest Support was received from the National Health Service Executive (Trent Research & Development).
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ABSTRACT |
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Aims To examine acts of aggression in first-episode psychosis.
Method Subjects with a first-episode psychosis were ascertained from a defined catchment area (Nottingham, UK) and reassessed at 3 years (n=166) using clinical interview, informants, health care and forensic records.
Results Of the subjects, 9.6% demonstrated at least one act of serious aggression (defined as weapon use, sexual assault or victim injury) during at least one psychotic episode and 23.5% demonstrated lesser acts of aggression (defined as all other acts of aggression). For all aggressive subjects (33.1%), unemployment (OR=3.6, 95% C11.6-8.0), comorbid substance misuse (OR=3.1, C1 1.1-8.8) and symptoms of overactivity at service contact (OR=6.9,C1 2.7-17.8) had independent effects on risk of aggression.
Conclusions We confirmed some previously reported demographic and clinical associations with aggression in first-episode psychosis but no relationship with specific psychotic symptoms or diagnostic groups was observed.
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INTRODUCTION |
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This study aimed to examine aggressive acts associated with an epidemiologically defined cohort of patients with a first-episode psychosis presenting to secondary psychiatric services and followed up 3 years later. Our objectives were:
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METHOD |
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Follow-up procedure
Follow-up assessments took place between June 1995 and May 1997, as close
as possible to 3 years after first contact. One hundred and forty-three direct
interviews (86%) were completed, with the remainder relying on other clinical
material. We obtained informed consent to interview subjects, to examine their
records and to interview their informal carers.
Assessment variables
Diagnosis
The diagnostic process is described by Brewin et al
(1997). Briefly, symptoms were
derived from ratings of the Schedules for Clinical Assessment in
Neuropsychiatry (SCAN) interview (World
Health Organization, 1994), supplemented by other record sources
and informant information. Where direct interview was impossible, other
information sources, mainly hospital notes, were rated using the Item Group
Checklist (IGC; World Health Organization,
1994), according to SCAN rules. When all data had been collected,
meetings were held between fieldworkers and the authors G.H. and I.M. and
consensus diagnoses were made using ICD10
(World Health Organization,
1992).
Personality was evaluated using the Personality Assessment Schedule (PAS; Tyrer & Alexander, 1988) and clinical consensus Axis II diagnoses for ICD10.
Symptoms
We re-coded 17 of the items in the IGC into a binary format (presence of a
symptom, rating>1). Items were chosen to reflect symptoms implicated in
violent behaviour as best evidence from previous research. These items then
were divided into three symptom subgroups: psychotic, behaviour and
threat-control-override (TCO) (see Appendix). Patients were
placed in high or low categories, dichotomised by
median scores in each subgroup.
Mode of illness onset (speed of evolution of symptoms) was estimated retrospectively using the Operational Criteria Checklist (OPCRIT; McGuffin et al, 1991), broadly categorised as acute if less than 1 month or insidious if greater than 6 months. The Scale for the Assessment of Negative Symptoms (SANS; Andreasen, 1982) was also administered.
Acts of aggression
Source of data. Offending behaviour (self-reported violence,
previous arrests, convictions and imprisonment for violence) was recorded from
the Psychiatric and Personal History Schedule
(Jablensky et al,
1992), follow-up assessments, psychiatric, community mental health
team and general practitioner records and legal reports where available.
Three-year follow-up assessment included questions about the nature and
frequency of any aggression; the dates of such episodes were obtained
exclusively from records. Not all patients consented to access to official
offending data, such as Criminal Records Office information.
Untoward incident forms (completed by staff following acts of physical disturbance by in-patients, day or out-patients) were obtained for the study period. These forms also recorded when subjects were absent without leave from in-patient wards.
Definition and classification. Acts of aggression were classified according to severity and timing within an individual's illness episode.
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Other variables
The Mental Illness Needs Index (MINI;
Glover et al, 1998)
was determined from each subject's postcode and dichotomised into proxy
measures of low (>110) or high (<110) deprivation scores.
Data analysis
Demographic and clinical characteristics were reported using proportions,
means or medians according to their measurement level (discrete or continuous)
and distribution (normal or skewed).
Stepwise logistic regression analyses were used to identify clinical and demographic characteristics associated with aggression. Separate analyses were conducted for all acts of aggression and for serious aggression. For each model, odds ratios with 95% confidence limits were reported for variables meeting the entry criteria. The 11 independent variables (chosen for their previously reported or hypothesised association with aggression and mental disorder) were age, gender, employment, history of violent convictions, MINI score, diagnosis at first contact, comorbid substance misuse diagnosis, total symptom score, psychotic symptom score, behaviour symptom score and TCO score.
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RESULTS |
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Details of aggressive acts
Details of timing and severity of all aggressive acts are presented in
Fig. 2 and
Table 1. A description of
victims of all assaults committed in episode is shown in
Fig. 3.
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Fifty-five (33.1%) subjects were responsible for 166 aggressive acts towards others during periods B and C, some subjects being responsible for several incidents within one time period (e.g. two subjects were responsible for 44 of the aggressive incidents during period C). Of these, 16 subjects (9.6% of the total sample or 29.1% of the aggressive group) demonstrated at least one act of serious aggression in periods B and/or C and 4 (2.4%) exhibited aggressive behaviour in all time periods. All but one of the 35 subjects who were aggressive during period C were judged by investigators to be ill at the time of such incidents.
For 20 subjects (71.4% of the subjects exhibiting aggression in period B) aggression at presentation led directly to psychiatric contact, and in 18 cases the police were involved (10.8% of the total sample).
Demographic characteristics of subjects exhibiting any aggression towards others while in episode compared with non-aggressive subjects are shown in Table 2 and their clinical attributes in Table 3. Other features characteristic of subjects who exhibited aggression after service contact were high rates of absconding from in-patient care (34.3%, OR=16.6, 95% CI 4.9-55.9) and increased compulsory admissions over the following 3 years (mean number of sections=2.2 and s.d.=1.5 v. 0.11 and 0.32 for non-aggressive subjects; t=-2.4, P=0.017).
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For the 29.1% of aggressive subjects who exhibited serious aggression while ill, a comparison is shown in Table 4 with subjects exhibiting less serious aggression (only positive statistical or relevant associations are shown).
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Other than the characteristics shown in Table 4, demographic or clinical features failed to discriminate between lesser and serious aggression. Although more subjects committing serious aggression while ill but before contact had a slow mode of illness onset compared with those committing less serious aggression during the same period (6/8 v. 6/20, OR=7.0, 95% CI 1.1-45.2, P<0.05), their DUI was not significantly longer (median 554 days v. 128 days, Mann-Whitney U=48.0, P=0.10).
Symptoms at baseline
Psychotic symptoms such as delusions, hallucinations and passivity
phenomena were common at service contact in both aggressive and non-aggressive
groups with no statistically significant differences. For example, persecutory
delusions were noted in 71.2% of non-aggressive subjects and in 83.3% of
subjects who exhibited an aggressive act, with 19.8% of non-aggressive
subjects describing delusions of passivity compared with 12.7% of aggressive
subjects. A summary of IGC symptom group findings is shown in
Table 3.
Comparisons of positive scores on individual item groups (IG) from the IGC, recorded at service contact, between subjects who were or were not aggressive after service contact (period C) showed that the aggressive group were significantly more likely to exhibit overactivity (IG19: OR=2.2, 95% CI 1.1-4.5), emotional turmoil (IG31: OR=2.9, 95% CI 1.4-5.6), socially embarrassing behaviour (IG34: OR=4.0, 95% CI 1.7-9.7) and problems in non-verbal communication (IG37: OR=2.5, 95% CI 1.1-6.0). Subjects exhibiting aggression during period B were also distinguished by symptoms relating to overactivity (IG19: OR=2.8, 95% CI 1.2-6.5), emotional turmoil (IG31: OR=4.1, 95% CI 1.7-9.5), socially embarrassing behaviour (IG34: OR=3.2, 95% CI 1.2-8.0) and problems in non-verbal communication (IG37: OR=3.1, 95% CI 1.3-7.6) as well as self-neglect (IG38: OR=3.5, 95% CI 1.3-9.5), but were less likely to exhibit delusions of persecution (IG30: OR=2.5, 95% CI 1.1-5.0), delusions of reference (IG29: OR=2.5, 95% CI 1.25-5.0) or bizarre delusions (IG27: OR=2.5, 95% CI 1.1-5.0).
Seriously aggressive subjects were also characterised by overactivity (IG19: OR=3.4, 95% CI 1.2-9.8) and deficits in non-verbal communication (IG37: OR=5.5, 95% CI 1.9-16.2) and were less likely to exhibit bizarre delusions (IG27: OR=5.0 95% CI 1.4-10.0). There was no significant difference between total SANS scores for aggressive and non-aggressive subjects (t=-0.37, d.f.=147, P=0.71).
Substance misuse
No data on substance misuse were available for 14 (8.4%) cases. Thirteen
(8.6% of 152) subjects had primary substance-related psychoses (ICD10
F1x) and 15 (9.9%) other subjects had ICD10 comorbid substance
misuse and psychotic disorders, mostly illicit drugs (93.3%) rather than
alcohol. Comparisons between substance misuse variables for aggressive and
non-aggressive subjects are shown in Table
3.
Personality
The PAS data were unavailable for 74 (44%) subjects and therefore were not
evaluated. Consensus F60 personality disorders were recorded for six subjects:
one schizoid, one emotionally unstable and four dissocial personality
disorders. No statistical associations were found between those with comorbid
personality disorder and aggression.
Multivariate analyses
Two multiple logistic regression models were used to assess the risk of
subjects exhibiting either any aggression or serious aggression while in
episode. Of the 11 independent variables, age, gender, diagnosis at first
contact, history of violent convictions, MINI score, total symptom severity
score and psychotic symptom score did not meet the entry criteria. A high
behaviour symptom group score (OR=6.9, 95% CI 2.7-17.8), comorbid substance
misuse diagnosis (OR=3.1, 95% CI 1.1-8.8) and being unemployed (OR=3.6, 95% CI
1.6-8.0) all had an independent effect on the risk of exhibiting any
aggression. A high TCO score had an independent effect on reduced risk of any
aggression (OR=2.8, 95% CI 1.3-6.3).
For the model of serious aggression while in episode, a history of convictions for violence (OR=12.6, 95% CI 3.5-45.1) was the only independent variable to meet the entry criteria other than high TCO score, which was negatively associated with risk (OR=4.1, 95% CI 1.2-14.7).
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DISCUSSION |
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Methodological strengths and limitations
Criticisms of previous studies examining the relationship between violence
and mental disorder have been described in the MacArthur Violence Risk
Assessment (MVRA) Study (Steadman et
al, 1994).
Briefly, there are three types of problem: use of static predictor variables (usually socio-demographic variables) rather than dynamic (symptom profile or timing of violent behaviour) variables; narrowly defined patient samples in-patients (Raja et al, 1997), high risk discharges from secure psychiatric or prison facilities (Rice & Harris, 1995) or single diagnostic groups (Humphreys et al, 1992) and data-sets restricted to individuals arrested or re-admitted to hospital (Wessely et al, 1994; Tiihonen et al, 1997). This study therefore sought to use a representative first-episode community-based sample, a broad diagnostic range of psychotic disorders and multiple data sources.
Our findings have several limitations. First, and of greatest hindrance to conclusions about prevalence, is the absence of a non-psychosis comparison group representative of the population from which our subjects were taken.
Second, the overall study was not designed primarily to obtain data on aggression or offending. Because difficulties with confidentiality and consent were encountered in accessing statutory criminological data, an incomplete criminological data-set probably reduced the prevalence of reported offending. Although the use of multiple data sources (e.g. informant interviews or psychiatric records) has been shown to increase significantly the reported prevalence of violence (Steadman et al, 1998), our findings still have limitations. For example, even in prospective studies such as the MVRA Study, subject attrition can be high, leading to restrictions in collection and analysis of violence-related data. Sources such as psychiatric case notes have been shown to underestimate convictions for violence among mentally disordered offenders by almost 50% in a UK sample of homicide perpetrators (Shaw et al, 1999). Additionally, use of untoward incident records may bias the reporting of aggressive incidents after service contact and in in-patient settings: either overreporting due to individuals' increased exposure to the scrutiny of health care staff or underreporting because aggression may be accepted by staff as symptomatic of mental disorder.
Third, modifications made to the IGC to allow comparison of symptoms across the whole cohort have yet to be validated as a means of assessing symptom clusters. However, the SCAN interview is widely used and good reliability between raters was demonstrated for this study (Brewin et al, 1997). We chose particular item groups and then adopted sub-scales based upon established empirical evidence for their association with violence. This approach has face validity although it could be criticised for focusing on particular target symptoms, thus biasing findings towards certain symptoms at the expense of other previously unreported but potentially important symptom areas.
Lastly, because the study was not conceived to ascertain clinical and contextual variables at the precise time of all aggressive acts, it was not always possible to elicit retrospectively (either from patients or informants) the precise motives after illness onset, although most attributed aggression after service contact to illness. Also, only those patients whose pre-contact aggression led to immediate admission received a SCAN interview temporally related to the incident. For the remaining subjects, we drew conclusions from SCAN interviews shortly after service contact about the relationship between psychopathology at service contact and at times of aggression. It could be argued also that the differentiation of illness episode into specific time periods is arbitrary, particularly when change in behaviour (rather than emergence of first psychotic symptom) was the criterion used. This could be relevant if different risk factors for aggression prevail at difference time periods of illness.
Type and frequency of aggression towards others
Approximately one-third of subjects exhibited aggressive behaviour during
periods B and C and one-sixth after the onset of symptoms but prior to service
contact. Comparisons with other UK samples are limited by diagnostic
heterogeneity. However, the proportion of subjects with schizophrenia
exhibiting aggression prior to contact (10/54 or 18.5%) is similar to another
UK study (21%) (Humphreys et al,
1992) but less than that described for developed countries (31.5%)
in the World Health Organization's study on the Determinants of Outcome of
Severe Mental Disorders (DOSMD; Volavka
et al, 1997).
Aggressive acts were more common after service contact. Despite this, only four (2.4%) subjects demonstrated aggression in all the time periods studied (i.e. premorbidly and after illness). Serious aggression was more prevalent before onset of illness and diminished in frequency in proportion to less serious aggression after onset and contact with secondary services. However, the overall number of subjects committing lesser acts of aggression increased. Although this may relate in part to reporting bias after service contact, further analysis of the timing of violent events relative to symptoms and illness course is required.
Our findings regarding the victims of aggression by subjects with psychosis are in broad agreement with the MVRA Study (Steadman et al, 1998), where family and acquaintances form the majority of victims. Further study of the location, social context and social networks of subjects with psychosis in relation to aggression is needed.
Diagnosis, symptoms and violence
Excluding substance misuse (ICD10 F1x) comorbidity,
diagnostic group alone did not confer any special risk of aggression,
regardless of aggression type or severity. This contrasts with other studies
of serious offending, which report an increased risk for schizophrenia of both
homicide (Eronen et al,
1996) and violent conviction
(Tiihonen et al,
1997).
In agreement with recent findings from the MVRA Study (Appelbaum et al, 2000), we did not confirm previous reports linking specific psychotic symptoms and aggression. We found that although delusions, hallucinations and passivity phenomena were common, they did not specifically distinguish subjects who were aggressive, either in isolation or as the TCO syndrome. We also confirmed Appelbaum et al's (2000) finding that higher TCO scores at baseline assessment were inversely related to the risk of further aggression, serious or otherwise. Such findings, relating to an inception rather than a discharge cohort, may add weight to Appelbaum et al's conclusions that "presumed risk of violence associated with delusions per se does not justify hospitalisation of a patient, in the absence of other indicators of violence risk or of other reasons for inpatient treatment".
Symptoms that were associated with aggression and present at service contact were apparent in two areas. First, behavioural symptoms, such as overactivity and emotional turmoil, had large and independent effects on risk of aggression. This has some precedence in the symptoms of excitement found in acute-onset disorders during the DOSMD study (Volavka et al, 1997). Second, symptoms related to aspects of negative symptoms and deficits in communication appeared to be characteristic of subjects, mainly younger men with insidious illness onset, who exhibited serious aggression towards others and specifically after illness onset and before service contact. However, higher global ratings of negative symptoms were not characteristic of these subjects.
In addition to insidious illness onset and past history of convictions for violence, subjects with psychosis who demonstrated serious aggression also had longer periods of untreated illness. Duration of untreated illness has attracted attention as an important factor associated with outcome across a number of domains (McGorry et al, 2000). Although the association with aggression could provide opportunities for reducing the DUI in order to diminish indirectly the risk of aggression, the relationship may be an artefact. Because the length of period B varied considerably (from a few days to over 10 years), it is possible that the connection between the DUI and aggression represents a longer period at risk.
Only a small number of subjects received any Axis II diagnosis. Our findings are likely to represent an underestimation of personality disorder, owing to the absence of interview- or informant-based personality data for all subjects.
Substance misuse and violence
Previous research has identified a relationship between substance misuse
and violence, either alone or in combination with major mental disorder
(Swanson et al, 1990;
Tiihonen et al, 1997;
Steadman et al,
1998). In a UK sample, Scott et al
(1998) reported that
individuals with comorbid psychosis and substance misuse are more likely to
exhibit hostile behaviour and assaults than those with psychosis alone.
We confirmed that ICD10 F1x diagnostic comorbidity, but not primary drug-related psychosis, at onset had an independent effect on the risk of subjects exhibiting aggression during a psychotic episode. Individuals with drug-related comorbidity were nine times more likely to exhibit aggression after service contact. Whether this represents reporting bias and how such individuals' substance misuse covaries with their psychotic disorder over time requires further study. Comorbid alcohol misuse was not a significant association for violence, as reported in the DOSMD study (Volavka et al, 1997).
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Clinical Implications and Limitations |
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LIMITATIONS
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APPENDIX |
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Total symptom severity rating
(maximum score=17, low=0-5, high=6+)
Psychotic symptom subgroup
(maximum score=11, low=0-4, high=5+)
Behaviour symptom subgroup
(maximum score=6, low=0, high=1+)
Threat-control-override (TCO) symptom subgroup
(maximum score=6, low=0-2, high=3+)
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ACKNOWLEDGMENTS |
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Received for publication October 22, 1999. Revision received December 7, 2000. Accepted for publication December 11, 2000.
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