School of Psychological Sciences, University of Manchester, UK
School of Community Based Medicine, University of Manchester, UK
Department of Psychology and Social Behavior, University of California at Irvine, California, USA
School of Psychological Sciences, University of Manchester, UK
Correspondence: Gillian Haddock, School of Psychological Sciences, Zochonis Building, University of Manchester, Oxford Road, Manchester M13 9PL, UK. Email: gillian.haddock{at}manchester.ac.uk
None. Funding detailed in Acknowledgements.
|
|
|---|
Aggression and violence are serious problems in schizophrenia. Cognitive–behavioural therapy (CBT) has been shown to be an effective treatment for psychosis although there have been no studies to date evaluating the impact of CBT for people with psychosis and a history of violence.
Aims
To investigate the effectiveness of CBT on violence, anger, psychosis and risk outcomes with people who had a diagnosis of schizophrenia and a history of violence.
Method
This was a single-blind randomised controlled trial of CBT v. social activity therapy (SAT) with a primary outcome of violence and secondary outcomes of anger, symptoms, functioning and risk. Outcomes were evaluated by masked assessors at 6 and 12 months (trial registration: NRR NO50087441).
Results
Significant benefits were shown for CBT compared with control over the intervention and follow-up period on violence, delusions and risk management.
Conclusions
Cognitive–behavioural therapy targeted at psychosis and anger may be an effective treatment for reducing the occurrence of violence and further investigation of its benefits is warranted.
|
|
|---|
|
|
|---|
Participants
Participants were in-patients and out-patients, recruited from mental
health services from five National Health Service trusts in the North West of
England between 2000 and 2004. Potential participants were identified from
mental health staff and from case-note search. Case notes were screened to see
whether potential participants met initial inclusion criteria (see below for
further details) and those meeting the criteria were interviewed using the
Positive and Negative Syndrome
Scale7 (PANSS) to
ascertain whether psychotic symptoms were present. Those who met all criteria
were asked whether they would be willing to take part in the trial and those
giving consent were subject to the full assessment described below. The
inclusion criteria were as follows.
Eligible, consenting potential participants were assessed by masked raters at baseline, after 6 weeks (baseline 2), at end of treatment (6 months) and at follow-up (12 months). Masking was maintained by ensuring therapists and assessors were housed in separate accommodation, therapy files were kept separately from data and clinical staff was repeatedly instructed not to disclose any knowledge of therapy group to assessors.
Primary outcome: assessment of aggression and violence
Data on acts of aggression and violence were collected at four time points
from case notes by masked assessors:
Data were collected on eight aggression and violence variables taken from the Ward Anger Rating Scale (WARS; see below, details available from R.W.N. on request) and were recorded if a description of an event was written in any part of the case notes during the target period. From these data, the following three variables were computed: total number of any incidents across each of the four time points by group; number of verbal incidents across each time period by group; and the number of acts of physical violence carried out over the four time periods by group. In addition, a dichotomous variable of `no violence' v. `presence of violence' over the intervention and follow-up period was recorded for each individual.
Secondary outcomes
Staff-rated aggression and anger
The Ward Anger Rating Scale (WARS) (details available from R.W.N. on
request) was used; this is a two-part scale (A and B) completed by a staff
member who has observed participants' behaviour during the previous week. Part
A consists of 18 dichotomous, weekly ratings regarding verbal and physical
behaviours associated with anger and aggression. Eight of the Part A items
relate to verbal and physical aggression to property or others (e.g. verbally
abused someone, verbally threatened to attack staff member). These were summed
to form an index of `angry–aggressive behaviours'. Part B consists of
seven items regarding affective–behavioural attributes related to anger
(e.g. angry or annoyed, irritable or grouchy) that staff rate on a five-point
scale (0–4). The sum of the seven Part B anger attribute ratings produce
an `anger attributes index'.
Good interrater reliability, internal consistency and validity have been demonstrated for the WARS in forensic and in-patient populations.11,12
Assessment of self-reported anger
The Novaco Anger Scale and Provocation
Inventory13
(NAS–PI) was used: it is a self-report instrument containing cognitive,
arousal and behavioural sub-scales, which comprise a total score. The
sub-scales relate to the three dispositional domains described by
Novaco.14 It has
received independent
validation15 and
has shown good internal reliability and test–retest
reliability.13,14
The Provocation Inventory is an anger reaction inventory that was developed to
accompany the NAS. It has 25 items providing an index of anger intensity and
generality across a range of potentially provocative situations. The
Provocation Inventory has been independently validated and has good
psychometric
properties.13
Symptom assessment
The PANSS7 was
used to rate severity of psychotic symptoms. Assessors were trained to a high
standard of interrater reliability (PANSS positive sub-scale inter-class
correlation=0.905, 95% CI 0.753–0.980).
The Psychotic Symptom Rating Scales (PSYRATS)16 was also used to assess symptoms. This uses semi-structured interviews that assess dimensions of psychotic symptoms. They comprise two scales that rate auditory hallucinations and delusions. The scales have been used widely to assess these symptoms and have good psychometric properties with individuals with chronic, and acute, psychosis.17 Assessment of functioning was carried out using the Global Assessment of Functioning scale (GAF).8
Assessment of risk
The Historical, Clinical, Risk Management–20 (HCR–20)
scale18 was used to
assess risk; this 20-item scale consists of three subscales relating to risk
of violence. The three sub-scales are: historical factors; clinical factors;
and risk factors in relation to the future. Each scale is scored separately by
raters who are informed from multiple sources. The scale has been widely
evaluated with in-patient, community and forensic groups and has been shown to
have good interrater reliability and predictive validity in relation to future
violence. The historical scale was only carried out at baseline and the
clinical and risk scales were carried out at baseline and follow-up only.
Participant risk status was assessed during the intervention and follow-up period from data collected from multiple sources. Any change in risk management was recorded by trial staff during the whole of the study period. This was also verified from case-note records at the end of the trial by research assistants. For example, changes in amount of freedom within the ward environment, changes in access to sharp objects, increase in access to hospital grounds. The nature of the change in leave status was recorded and, retrospectively, each individual was categorised as either receiving no change or increase in the risk management, or decrease in the risk management.
Treatment
Participants were randomly allocated to group by personnel independent of
the trial using a computer-generated randomisation procedure stratified for
gender, presence of substance misuse, severity of anger, presence or absence
of actual violence in the last 12 months and facility (out-patient v.
in-patient). Participants were allocated to either:
The rationale for the integrated CBT was based on two main factors. First, it was envisaged that this group of individuals might show considerable problems in engaging with therapy and hence the therapy was enhanced with motivational interviewing strategies to improve the potential for engagement in CBT. Second, it has been demonstrated that both psychotic symptoms and anger are implicated in the occurrence of violence, hence strategies to reduce the severity of both were included. The SAT treatment was designed to control for non-specific elements of therapy such as having a one-to-one relationship with an empathic therapist. Both treatments consisted of 25 sessions carried out by therapists who had been trained in the protocol and received ongoing supervision. Therapists who carried out the CBT programme met the British Association of Behavioural and Cognitive Psychotherapies' Minimum Training Standards for the practice of CBT and had prior experience of applying CBT for people with psychosis. Stringent procedures to manage treatment fidelity were employed as follows.
Statistical analysis
Data were analysed using SPSS for Windows version 14. All analyses were
conducted on an intention-to-treat basis. Chi-squared analysis was used to
assess differences between groups on occurrence of violence and change in risk
management. Non-parametric analysis was carried out on violence frequency data
and staff-rated anger. Group differences on other quantitative outcomes were
examined in a repeated measures analysis using the SPSS mixed model REML
procedure (SPSS version 12), contrasting baseline and baseline 2 scores with
end of treatment (time 1) and follow-up (time 2) scores with secondary outcome
variables of symptoms, functioning and anger. The significance tests of
interest were for the end of treatment (time 1)x treatment group and
follow-up (time 2)xtreatment group interactions. Where scores from
assessment measures deviated significantly from a normal distribution, log
transformed scores were attempted and where distributions remained skewed or
there was significant kurtosis, non-parametric statistics were employed.
|
|
|---|
![]() View larger version (13K): [in a new window] [as a PowerPoint slide] |
Fig. 1 Progression through the trial.
|
|
View this table: [in a new window] |
Table 1 Demographic characteristics of sample
|
Therapy participation
Of the 77 participants, 3 decided not to take part in therapy (2 CBT, 1
SAT) and 1 was transferred to a facility out of region making visits not
possible. One person died of natural causes before the end of treatment and is
not included further in the analysis. Of the rest, the mean number of sessions
attended was 17.0 (s.d.=6.8) sessions for CBT and 17.4 (s.d.=6.6) sessions for
SAT. The mean number of minutes of therapy received was 787.7 (s.d.=356.2) for
CBT and 894.3 (s.d.=413.3) for SAT. There were no significant differences
between the groups on the number of sessions (F(1,75)=0.89,
P=0.77) or minutes of therapy received (F(1,75)=1.45,
P=0.23). Of the 73 participants who took part in therapy, all but 8
received at least 10 sessions of therapy. The eight (four from CBT, four from
SAT) received between three and nine sessions. Overall, 38 people received CBT
and 39 received SAT. There was little difference between the groups in terms
of the age of the participants (mean age: CBT=35.7 years, s.d.=12.5; SAT=33.9
years, s.d.=9.7).
Primary outcome: case-note identification of aggression and violence
There was little difference between the treatment groups pre-trial entry (3
months prior to baseline 1) or between baseline 1 and 2 (pre-treatment
intervention) on numbers of people who were aggressive or violent or on total
incidents of aggression and violence.
Overall over the treatment period, there were no significant differences
between the groups on the number of people who had no incidents of violence or
aggression v. the number who had one or more incidents
(
2=2.351, d.f.=1, P=0.125). However, the CBT group
had a significantly lower number of incidents during the treatment period
(P=561.0, P=0.039). Over the follow-up period, there was no
significant difference between the number of people in each group that carried
out aggressive or violent acts (
2=0.160, d.f.=1,
P=0.689) or on total number of incidents (Mann–Whitney
U=697.0, P=0.594). The total number of incidents of verbal
or physical aggression recorded from case notes over the intervention and
follow-up period by group is shown in Table
2.
|
View this table: [in a new window] |
Table 2 Total number of incidents for each group by case note identification over
the treatment and follow-up period
|
There were no significant differences between the groups over the treatment
period on the numbers of people who engaged in verbally aggressive acts
(
2=1.597, d.f.=1, P=0.256) or on the number of
incidents of verbal aggression (U=611.0, P=0.150). This was
similar for the follow-up period on number of people (
2=0.687,
d.f.=1, P=0.490) and number of incidents (U=555.5,
P=0.765).
Over the treatment period, there were no significant differences between
the groups on the number of people who were physically aggressive
(
2=2.160, d.f.=1, P=0.142) or the total number of
incidents involving physical aggression (U=653.5, P=0.172).
However, over the follow-up period, there were significantly more people who
had been physically aggressive in the SAT group compared with the CBT group
(
2=8.081, d.f.=1, P=0.004) and there was a
significantly lower number of physically aggressive incidents in the CBT group
(U=466.0, P=0.028).
Secondary outcomes
Staff-rated anger and aggression
The number of participants scoring positive for aggressive behaviours on
the WARS–A scale as rated by staff over a 1-week time period did not
differ significantly between the two groups (CBT n=7 (end of
treatment) and 6 (at follow-up); SAT n=12 (end of treatment) and 7
(follow-up)).
Scores on the WARS–B (the anger indices outcome) indicated a decrease overall at end of treatment and follow-up on the amount staff thought the participants were displaying anger. However, there were no significant time 1 or time 2xgroup interactions and we conclude that there are no differences between the two treatments on this outcome. Raw scores at each time point can be found in the online Table DS1.
Anger
No significant time 1 or time 2xgroup interactions were found on NAS
total anger scores, on any sub-scales or on the Provocation Inventory. The NAS
and Provocation Inventory raw scores are shown in Table DS1.
Symptom outcomes
The PANSS, PSYRATS and GAF raw scoresxtreatment group at the four
time points are shown in Table DS1. There is some sign of improvement in these
symptoms over time but there were no significant time 1xgroup or time
2xgroup interactions, indicating that neither treatment was superior to
the other. However, there were significant interactions between group and
treatment on total PSYRATS delusions (but not auditory hallucinations)
outcomes at end of treatment (but not follow-up) with those receiving CBT
showing greater reductions in the severity of delusions (F=9.469, 1
and 75.2 d.f., P=0.003)
Functioning
Again, there was an improvement in functioning over time in both groups,
but there were no timexgroup interactions.
Risk
Change on the HCR–20 was assessed on the clinical and risk scales of
the HCR only. Data were collected at baseline 1 and follow-up. There is little
evidence of any treatment group differences.
There were significant differences between the groups regarding security
risk (in-patients only, n=48), with the SAT group having more
participants who were in the `no change/increase risk management' category
than those who received CBT, and those receiving CBT having more participants
who decreased the amount of risk management required (
2=6.19
(1), P=0.014).
|
|
|---|
Despite the benefits, it is unclear what the main mechanism of change was. Benefits were observed for both CBT and SAT on symptoms overall, however, the CBT group had a greater improvement in delusions which may have accounted for the greater impact on reducing physical violence, especially as particular delusions have been consistently linked with increased levels of violence in schizophrenia.4,21,22 When the descriptive data were examined, there was a relatively large decrease on the PSYRATS delusions factor of `distress'16 in the CBT group compared with a slight increase in the SAT group. It is possible that CBT provided additional strategies to produce a change, not only in the severity of the delusions, but also in the distress associated with them, a benefit not produced by SAT. Whether this was sufficient to produce the reduction in physical aggression seen in this group is unclear.
Limitations and strengths
There are a number of limitations that should be considered when
interpreting the results from this study. First, the sample size was
relatively small which may have limited the power of the study to detect
treatment differences. Estimates of power based on a review of previous trials
of CBT in schizophrenia recommend at least 70 in each group to show
differences between
groups.1 Similarly,
the multiple testing in relation to the secondary outcomes may have increased
the likelihood of the positive findings happening as a result of chance,
particularly in relation to the positive psychotic symptom outcome.
Furthermore, the sample was quite heterogeneous with a mix of in-patients,
out-patients and those residing in high-security environments. It is possible
that the interventions may have had different impacts in different
environments. However, an exploratory analysis of the in-patient participants
in the sample on violence, symptoms and anger showed no differences to the
pattern of findings found for the whole sample. In addition, this study failed
to address issues relating to personality in relation to outcome or in the
treatment protocol. This may be necessary in future studies as personality
factors may be important predictors of violence for some individuals and may
be influential in the degree to which an individual engages with
therapy.23
Despite these limitations, strengths of the study included:
These are important outcomes particularly for those people residing in in-patient or secure environments where risk and prediction of future risk are especially pertinent. The positive findings regarding CBT are promising and suggest optimism for further exploration of psychological treatments for people with psychosis and problems with aggression and violence. However, some further modifications and fine tuning of the treatment may be necessary. In the light of these preliminary findings, further evaluation of the approach is warranted.
|
|
|---|
|
|
|---|
Related articles in BJP:
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||