Inpatient violence and aggression: a literature review

196 Pages·2011·1.65 MB·English

Inpatient violence and
aggression: a literature
review

Report from the Conflict and Containment
Reduction Research Programme

Len Bowers

Duncan Stewart

Chris Papadopoulos

Charlotte Dack

Jamie Ross

Husnara Khanom

Debra Jeffery

May 2011

Section of Mental Health Nursing

Health Service and Population Research

Institute of Psychiatry
Kings College London
1. BACKGROUND

Mentally ill people in hospital sometimes behave aggressively. They may try to harm
other patients, staff, property or themselves. In the UK, the National Audit of
Violence found that a third of inpatients had been treatened or made to feel unsafe
while in care [Royal College of Psychiatrists 2007]. This figure rose to 44% for
clinical staff and 72% of nursing staff working in these units. Such aggression can
result in injuries, sometimes severe, to patients or to staff, causing staff absence and
hampering the efficiency of the psychiatric service. The ways in which aggressive
behaviour is managed by staff is contentious and emotive, and there is little evidence
or agreement about their effectiveness. This review aims to describe the available
research literature on the prevalence, antecedents, consequences and circumstances of
violence and aggression in psychiatric hospitals.

Our previous research has focussed on how to reduce of conflict and containment on
acute wards. By conflict we mean those things that threaten patient and staff safety,
such as aggression, rule breaking, drug/alcohol use, absconding, medication refusal,
self-harm/suicide etc. By containment we mean those things the staff do to prevent
these things occurring, or reduce the amount of harm that occurs, such as giving extra
medication, intermittent observation, constant observation, show of force, manual
restraint, coerced injections of medication, seclusion, time out, locking of the ward
door, and other security policies. This research indicates a complicated relationship
between conflict behaviours and containment, and that the behaviour and attitudes of
staff may influence both. It led to the development of the ‘City model’ describing the
ways in which staff factors can reduce rates of conflict and containment on wards.
Three processes are posited to create low conflict and containment: positive
appreciation of patients (kindness), emotional self-regulation of anger and fear
(tranquillity), and an effective structure of rules and routines for patients based upon
an ethical (not punitive) stance (orderliness). In addition to an analysis of the research
literature, therefore, each chapter considers the evidence for and against the City
Model and suggests lessons for future research.

2. LITERATURE SEARCH

Electronic searches of the main databases were conducted to locate studies of
psychiatric inpatient aggression published in English between 1960 and 2009.
Searches were conducted using the following databases: MEDLINE, PsychInfo,
Cochrane Clinical Trials, EMBASE Psychiatry, CINAHL and DARE and the
following keywords: (psychiat* or mental*) and (hospital or ward or inpatient or in-
patient) and (aggressi* or violen*). No attempt was made to search for unpublished
results. 4,353 references were identified. Papers from adolescent and geriatric
services were excluded. Resulting titles and abstracts were then inspected for
relevance. As the literature accumulated, further references were obtained by
following up citations.

A total of 997 hardcopy references were obtained. These were divided between five
researchers for detailed review and data extraction. Under the supervision of the lead
author, the researchers inspected the papers for relevance, eligibility and suitable
empirical data (quantitative or qualitative) which could be used for the review. The
final number of studies included in the review was 424.

A matrix (in Excel) was constructed with a number of headings including:
methodology, sample, definitions and setting used in the article; the patient profiles
(age, gender, ethnicity, diagnosis, treatment, marital status, family circumstances,
previous psychiatric history, etc); the rates of occurrence; times and places or
occurrence of the event; circumstances of event; antecedents and causes; relationships
between types of adverse events; patient motivations; staff related factors and
limitations. Each of the 424 articles was reviewed and analysed by extracting
data/evidence for the relevant sections in the matrix. Additional information not
directly fitting in the predefined categories, was collated in an ‘other findings’ column
and processed separately.

Definitions were provided for each item on the matrix to facilitate consistency of data
extraction. The initial ten matrix entries for each researcher were cross checked for
accuracy and correct interpretation by the lead author and another team member.
Direct feedback was provided and emerging issues or problems discussed among the
team. Progress with the data extraction phase of the review was monitored by regular
individual and group meetings for a period of six months. Having extracted data onto
the matrix, responsibility for analysis and write-up of specific sections of the review
was divided among the team. This phase of the review took five months to complete.
Written reports for each section were submitted to the lead author for feedback,
revisions and final editing, before being combined into a single document.
3. THE INCIDENCE OF VIOLENCE AND AGGRESSION

3.1 The studies reviewed
At least one measure of the rate of aggression or violence could be calculated for 128
papers. In some cases data had been extracted from multiple publications which
shared the same source data. These studies were only counted once in the analyses.
One Canadian study of treatment resistant patients reported an event based rate of
3696% [Ehmann et al. 2001] which was substantially higher than any other study, so
was excluded from further analysis as an extreme outlier. One study reported rates
from three European cities (London, Modena and Athens)[Bowers et al. 2005]. The
London data from this study was also reported elsewhere [Bowers et al. 2003], but
data for the other two cities are analysed separately. The final sample was 122
studies. Sixty-seven of the studies (55%) were retrospective analyses of official
incident records and/or patient notes, while 55 (45%) used descriptive data from other
sources such as surveys, interviews and observation recording instruments designed
for the study. Thirty-eight were case-control studies and six were classified as before
and after studies.

The studies were conducted in various types of setting, ranging from acute wards
(n=37, 30%), forensic units (n=36, 30%) to psychiatric hospitals with a mix of ward
types (n=40, 33%). In nine (7%) cases the type of ward was classified as ‘other’.
Most studies were conducted in the USA (n=35, 29%) or UK (n=31, 26%). Other
countries represented included Australia (n=14, 12%), Norway (n=6, 5%), Canada
(n=5, 4%), Netherlands (n=5, 4%), Sweden (n=4, 3%), Italy (n=4, 3%), Germany
(n=2, 2%), Israel (n=2, 2%) and Taiwan (n=2, 2%). The studies involved a total of
69,249 patients, with an average sample of 581.9 (SD=1,035.1) per patient-based
study.

The definition of violence and aggression differed widely between studies. Types of
violence recorded included physical violence, physical violence directed at staff only,
verbal aggression, aggression towards objects, self-harm and sexual aggression.
Almost all the studies included physical violence, but the inclusion of the other
categories of violence and aggression varied. Where patients were responsible for
more than one category of violence studies typically only recorded the most serious
incident. These complexities meant that the review could not accurately describe
rates for individual categories of violence.

3.2 Overall incidence
The incidence of violence was calculated for seven types of measure: patient based %
(violent patients/sample*100), event based % (incidents/sample*100); events per 100
admissions per month (incidents per month/admissions per month*100); patients per
100 admissions per month (violent patients per month/admissions per month*100);
events per 100 occupied bed days (incidents/total patient bed days*100); patients per
100 occupied bed days (violent patients/total patient bed days*100); and events per
100k population per year. The overall mean incidence of violence across all the
studies was as follows: 32.4% (SD=19.6) of patients, 224.8 (SD=378.8) event based
percentage, 182.8 (SD=366.8) events per 100 admissions per month, 26.2 (SD=18.0)
patients per 100 admissions per month, 3.14 (SD=5.4) events per 100 occupied bed
days, 0.42 (SD=0.32) patients per 100 occupied bed days, and 122.2 (SD=138.6)
events per 100k population per year.

A meta-analysis (with random effects) was conducted as an alternative method of
calculating an overall rate of violence. This has the advantage of taking sample sizes
into account. The analysis showed a combined rate of 30.7% (95% CI=28.4-33.0).
However, the I-squared measure of heterogeneity was 98.7%, substantially higher
than the 50% recommended as an indicator that combining studies for meta-analysis
may be invalid [Perera & Heneghan 2008].

Kernel density plots show that the distribution of each variable was not normally
distributed (Figures 1 to 6), with event based rates showing greater positive skew than
patient based rates. For the purposes of statistical analysis in this report, patient and
event rates were square root and log transformed respectively to reduce the influence
of extreme scores.

Figure 1: Distribution for patient based rate
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Figure 2: Distribution of event based rate
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Figure 3: Distribution of events per 100 admissions per month
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Figure 4: Distribution of patients per 100 admissions per month
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Figure 5: Distribution of events per 100 occupied bed days
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Figure 6: Distribution of patients per 100 occupied bed days
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3.3 Incidence by country and setting

Mean rates were calculated for countries and settings with at least two studies for each
type of measure (Table 1). Unfortunately, there was insufficient data to enable
comparable analysis of rates per 100 occupied bed days or per 100k population.
Countries were also ranked for each measure (Table 2).
Table 1: Mean violence rates by country and measure
Events per
100 Patients per Events per Patients per
Patient Event adms per 100 adms per 100 occ bed 100 occ bed
Country based % based % month month days days
Australia 36.85 150.72 109.67 31.58 9.09 0.63
Canada 32.61 81.46 36.27 18.77 0.70 0.40
Germany 16.06
Israel 16.73
Italy 20.28 27.47 8.99 8.21
Netherlands 24.99 186.69 220.21 31.79 3.50 0.56
Norway 33.47 471.85 460.78 32.47 10.19
Sweden 42.90 59.25
Taiwan 128.27
United
Kingdom 41.73 303.49 170.73 32.97 2.25 0.35
Unites States 31.92 341.87 302.47 16.92 0.16 0.14

Analysis using one way ANOVAs showed that none of the comparisons were
statistically significant. However, the highest proportion of violent patients was
found in Sweden, the UK and Australia. The lowest patient based rates were from
Germany, Israel and Italy. Despite having the highest proportion of patients involved
in violence Sweden had one of the lowest event based rates, suggesting that violent
patients in that country commit fewer violent acts than in others. The UK remained
one of the countries with the highest event based rate, but while the USA had the
second highest rate for this measure, it was sixth out of ten for patient based rates.
The highest event based rate was for Norway, but this were influenced by one
forensic study with a high level of violence (2069%)[Rasmussen and Levander 1996],
although the study only measured physical violence towards staff in a forensic unit.
Without this study the mean event based rate for Norway was 58.69, which was one
of the lowest rates and comparable to Sweden. Italy had the fewest violent patients
and events among the countries which had data available for both these measures.

When rates were standardised by the number of admissions per month, the proportion
of patients involved in violence was highest for Australia, UK, Norway and the
Netherlands. Around a third of patients per 100 admissions from these countries had
committed at least one violent act. Greater differentiation was apparent for
standardised event based rates. Again Norway had the highest event based rate,
reflecting the outlier in this country. The USA had the next highest rate followed by
the Netherlands and UK. A mean rate per 100 occupied bed days could be calculated
for only six countries. Nevertheless, Australia and Norway had by far the highest
event based results for this measure (this time the outlier study from Norway could
not be included in the calculations). Canada and the USA had the lowest rates.
Norway and Australia also had the highest patient based rate per 100 occupied bed
days, and the UK and US the lowest. International comparisons across these different
measures needs to be interpreted cautiously because the same studies did not
contribute to each average score, the proportion of studies from different settings
differed between the countries, the definition of violence varied and the number of
studies from some countries was small.

Table 2: Ranked mean violence rates by country (high to low)
Events per
100 Patients per Events per Patients per
Patient Event adms per 100 adms per 100 occ bed 100 occ bed
based % based % month month days days
Australia 3 5 5 1 2 1
Canada 5 7 6 5 5 3
Germany 10
Israel 9
Italy 8 9 7 7
Netherlands 7 4 3 4 3 2
Norway 4 1 1 3 1
Sweden 1 8
Taiwan 6
United
Kingdom 2 3 4 2 4 4
Unites States 6 2 2 6 6 5

Rates of violence would also be expected to be influenced by the type of psychiatric
service patients were recruited from. In particular, patients treated in forensic settings
are likely to be more violent than those from other settings, not least because the
majority are admitted specifically because of their violent behaviour [Coid et al.,
2001]. This was confirmed by statistical comparison of rates reported by studies
from forensic, acute and psychiatric hospital settings (Table 3). Nine studies which
could not be classified into these three categories were excluded from the analysis.
Mean rates for studies of forensic inpatient services were consistently higher than
those from an acute ward setting, except for rates per 100 occupied bed days. Raw
patient and event based percentages1 and those per 100 admissions were also
significantly higher in studies of forensic hospitals than those of whole psychiatric
hospitals (including a mix of ward types). There was an overall difference between
groups for patients per 100 occupied bed days, with a significant difference between
forensic and acute wards.

Table 3: Rates of violence by setting
Measure Acute Forensic Psych hosp F df p
Mean SD Mean SD Mean SD
Patient based rate 26.18a 15.07 47.71a,b 18.76 22.08b 14.33 21.60 2,87 0.000
Event based rate 71.56a 64.93 411.31a,b 516.08 120.537b 253.87 9.37 2,71 0.000
Events per 100 adms 48.89a 53.95 406.09 a,b 542.89 38.77b 46.05 12.01 2,39 0.000
Patients per 100 adms 20.14a 12.27 45.65 a,b 14.11 12.41b 7.76 20.25 2,35 0.000
Events per 100 occ beds 4.02 4.69 0.94 1.20 5.77 11.15 1.59 2,19 0.230
Patients per 100 occ beds 0.63a 0.26 0.28 a 0.30 0.15 0.04 4.83 2,16 0.023

1 A meta-analysis showed a similar trend, with a higher overall rate for forensic studies (45.8%, 39.6-
51.9) compared to acute wards (25.6%, 21.2-30.0) and psychiatric hospitals (20.8%, 18.0-23.6).
Again, however, I-squared values were above 90% for each setting.