The London-East Anglia Randomised Controlled Trial of Cognitive Behaviour Therapy for Psychosis II: predictors of outcome
Despite growing evidence of the effectiveness of cognitive-behavioural therapy (CBT) for psychosis, typically only about 50% of patients show a positive response to treatment. This paper reports the first comprehensive investigation of factors which predict treatment outcome.
In a randomised controlled trial of CBT for medication-resistant psychosis (see Part I) measures were taken at baseline of demographic, clinical and cognitive variables. Changes over time were assessed on the Brief Psychiatric Rating Scale and the relationship between potential predictor variables and outcome was investigated using analysis of variance and covariance.
A number of baseline variables were identified as predictors of good outcome in the CBT group. Key predictors were a response indicating cognitive flexibility concerning delusions (P = 0.005) and the number of recent admissions (P = 0.002). Outcome was less predictable in the control group and was not predicted by any cognitive variable.
Good outcome is strongly predicted in patients with persistent delusions by a cognitive measure, while this was not the case in controls. Thus we argue that positive outcome in CBT is due in part to specific effects on delusional thinking.
Available from: Neil Thomas
- "Around half the patients who receive CBTp in clinical trials fail to attain clinically significant benefits in symptoms , suggesting this approach is only suitable for some patients. Failure to respond has been associated with pre-therapy measures of resistance to considering alternatives to delusions , denying any possibility of being mistaken , and the patient failing to engage with the therapist’s model of reality during the therapy process . These observations suggest that the partial effectiveness of existing psychological treatment arose from some patients not being amenable to the process of belief modification which is so central to CBT. "
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Cognitive behavior therapy for psychosis has been a prominent intervention in the psychological treatment of psychosis. It is, however, a challenging therapy to deliver and, in the context of increasingly rigorous trials, recent reviews have tempered initial enthusiasm about its effectiveness in improving clinical outcomes. Acceptance and commitment therapy shows promise as a briefer, more easily implemented therapy but has not yet been rigorously evaluated in the context of psychosis. The purpose of this trial is to evaluate whether Acceptance and Commitment Therapy could reduce the distress and disability associated with psychotic symptoms in a sample of community-residing patients with chronic medication-resistant symptoms.
This is a single (rater)-blind multi-centre randomised controlled trial comparing Acceptance and Commitment Therapy with an active comparison condition, Befriending. Eligible participants have current residual hallucinations or delusions with associated distress or disability which have been present continuously over the past six months despite therapeutic doses of antipsychotic medication. Following baseline assessment, participants are randomly allocated to treatment condition with blinded, post-treatment assessments conducted at the end of treatment and at 6 months follow-up. The primary outcome is overall mental state as measured using the Positive and Negative Syndrome Scale. Secondary outcomes include preoccupation, conviction, distress and disruption to life associated with symptoms as measured by the Psychotic Symptom Rating Scales, as well as social functioning and service utilisation. The main analyses will be by intention-to-treat using mixed-model repeated measures with non-parametric methods employed if required. The model of change underpinning ACT will be tested using mediation analyses.
This protocol describes the first randomised controlled trial of Acceptance and commitment therapy in chronic medication-resistant psychosis with an active comparison condition. The rigor of the design will provide an important test of its action and efficacy in this population.
Australian New Zealand Clinical Trials Registry: ACTRN12608000210370. Date registered: 18 April 2008
- "Sotsky et al., 1991). Garety et al.'s (1997) finding that less pronounced delusion–conviction and cognitive flexibility were associated with better outcome seems to support this for patients with psychosis. It would therefore be interesting to test whether lower levels of reasoning biases predict better outcome. "
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ABSTRACT: This study investigates predictors of outcome in a secondary analysis of dropout and completer data from a randomized controlled effectiveness trial comparing CBTp to a wait-list group (Lincoln et al., 2012). Eighty patients with DSM-IV psychotic disorders seeking outpatient treatment were included. Predictors were assessed at baseline. Symptom outcome was assessed at post-treatment and at one-year follow-up. The predictor x group interactions indicate that a longer duration of disorder predicted less improvement in negative symptoms in the CBTp but not in the wait-list group whereas jumping-to-conclusions was associated with poorer outcome only in the wait-list group. There were no CBTp specific predictors of improvement in positive symptoms. However, in the combined sample (immediate CBTp+the delayed CBTp group) baseline variables predicted significant amounts of positive and negative symptom variance at post-therapy and one-year follow-up after controlling for pre-treatment symptoms. Lack of insight and low social functioning were the main predictors of drop-out, contributing to a prediction accuracy of 87%. The findings indicate that higher baseline symptom severity, poorer functioning, neurocognitive deficits, reasoning biases and comorbidity pose no barrier to improvement during CBTp. However, in line with previous predictor-research, the findings imply that patients need to receive treatment earlier.
Available from: Suzanne So
- "rather, they are enduring. There is, however, some weak evidence, that belief flexibility predicts conviction change in that there was a marginally significant association between baseline belief flexibility and change in conviction at 3 months, consistent with earlier research findings (e.g., Garety et al., 1997). Flexible thinking may render the person more open to experiences or ideas which change their conclusions. "
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ABSTRACT: Two reasoning biases, jumping to conclusions (JTC) and belief inflexibility, have been found to be associated with delusions. We examined these biases and their relationship with delusional conviction in a longitudinal cohort of people with schizophrenia-spectrum psychosis. We hypothesized that JTC, lack of belief flexibility, and delusional conviction would form distinct factors, and that JTC and lack of belief flexibility would predict less change in delusional conviction over time. Two hundred seventy-three patients with delusions were assessed over twelve months of a treatment trial (Garety et al., 2008). Forty-one percent of the sample had 100% conviction in their delusions, 50% showed a JTC bias, and 50%–75% showed a lack of belief flexibility. Delusional conviction, JTC, and belief flexibility formed distinct factors although conviction was negatively correlated with belief flexibility. Conviction declined slightly over the year in this established psychosis group, whereas the reasoning biases were stable. There was little evidence that reasoning predicted the slight decline in conviction. The degree to which people believe their delusions, their ability to think that they may be mistaken and to consider alternative explanations, and their hastiness in decision making are three distinct processes although belief flexibility and conviction are related. In this established psychosis sample, reasoning biases changed little in response to medication or psychological therapy. Required now is examination of these processes in psychosis groups where there is greater change in delusion conviction, as well as tests of the effects on delusions when these reasoning biases are specifically targeted. The Diagnostic and Statistical Manual, Fourth Edition, (Amer-ican Psychiatric Association, 2000) defines delusion as "A false belief based on incorrect inference about external reality that is firmly sustained despite what almost everyone else believes and despite what constitutes incontrovertible and obvious proof or evidence to the contrary" (p. 765). Thus, a delusional belief is incorrect; it is based on erroneous judgments about the world, and it is unresponsive to countervailing evidence. Biases of reasoning have been invoked to understand the process of delusion forma-tion, and limited data-gathering (jumping to conclusions; JTC) and a failure to think of alternative accounts to the delusion (a lack of belief flexibility) have previously been shown to be related to how
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