Elsevier

Schizophrenia Research

Volume 183, May 2017, Pages 22-30
Schizophrenia Research

A systematic review examining factors predicting favourable outcome in cognitive behavioural interventions for psychosis

https://doi.org/10.1016/j.schres.2016.11.021Get rights and content

Abstract

Psychosis is a debilitating mental health condition affecting approximately 4 persons per 1000. Cognitive behavioural therapy for psychosis (CBTp) has been shown to be an effective treatment for psychosis and is recommended by several national guidelines. CBTp does not work equally well with everyone, however, with some 50% of clients receiving little benefit. This review sets out to systematically assess the literature and methodological quality of a number of studies, which examine factors predicting successful outcome in CBTp. The databases CINAHL, Cochrane, EBSCO, EMBASE, ISI Web of Science, MEDLINE (Ovid), PsycARTICLES, PsycINFO, PubMed, and Scopus were electronically searched. English language articles in peer reviewed journals were reviewed. Search terms “psychosis”, “psychotic disorder”, “cognitive behavioural therapy”, “cognitive therapy”, “randomised controlled trial”, “predictor”, and “treatment outcome” in various combinations were used as needed. Only randomised controlled trials (RCTs) were included. Results suggest that female gender, older age, and higher clinical insight at baseline, each predicted better outcome in CBT interventions with psychotic patients, as did a shorter duration of the illness, and higher educational attainment. Several other factors, such as higher symptom severity at baseline, were suggestive of predictive capacity but further research to clarify was indicated. Providers of mental healthcare should consider these findings when offering CBTp. The onus is also on healthcare providers to better equip non-responders to CBTp. Further investigation into a limited number of predictive factors, with an agreed set of outcome measures, would allow future researchers more direct comparisons between studies.

Introduction

Psychotic disorders are a group of illnesses characterized by the experience of a range of unusual, often distressing, mental and emotional events such as delusions and hallucinations. Psychosis can be experienced by individuals having diagnoses of schizophrenia, bipolar disorder, and psychotic depression, or the psychosis may be drug-induced. Traditionally, clinicians and researchers have categorised psychotic symptomology into positive symptoms and negative symptoms. Positive symptoms are characterized by prominent delusions, hallucinations, positive formal thought disorder, and persistently bizarre behaviour; negative symptoms, by affective flattening, avolition, and attentional impairment (Andreasen and Olsen, 1982). A recent systematic review conducted in the United Kingdom (Kirkbride et al., 2012) found the prevalence of psychosis in the population at 4 per 1000, with the annual incidence rate at 32 cases per 100,000.

Cognitive behavioural therapy (CBT) has been shown to be an effective, evidence-based, treatment for many debilitating psychological difficulties such as depression and anxiety (Butler et al., 2006). In the past two decades growing evidence has demonstrated the effectiveness of using CBT with a population experiencing psychosis. A recent review of the efficacy of CBT for psychosis (CBTp) (Turkington et al., 2013) concluded that CBTp can show robust effect and strong patient acceptability (Morrison et al., 2012a). Several national guidelines e.g. Morrison et al. (2004) have recommended CBTp as a first-defence treatment, alongside antipsychotic medication, for both first-episode psychosis and drug-resistant psychosis. In Ireland, the Health Service Executive (HSE), in a National Clinical Care Programme, fully adopted the NICE (2009) guidelines and recommended all patients experiencing first-episode psychosis be offered CBT for psychosis, alongside medical treatment. A nationwide training programme was implemented in 2013 to equip frontline staff with CBTp skills (HSE, 2013).

Despite its demonstrated effectiveness, CBTp does not work equally well with everyone. In a recent review Lincoln et al. (2014a) report that, on average, 16% of patients discontinue CBTp, and of those who continue in therapy, approximately half do not show reliable symptom improvement (Wykes et al., 2008). Several studies have set out to examine which factors are predictive of positive outcome in CBTp with a view to optimising therapy provision.

The process of setting out to identify variables which are predictive of therapy success is well established in the research literature. For example, Ciao et al. (2015) examined factors predicting and moderating outcome in Family Based Treatment for bulimia, and found that older adolescents made more rapid advances in self-esteem in therapy. Button et al. (2015), in a related finding, demonstrated that older age of adult clients favourably predicted response to CBT for depression. In contrast, Torp et al. (2015) reviewed predictive factors in CBT for paediatric OCD, and found that children and adolescents who were older, and had more severe OCD had significantly poorer outcomes after 14 weeks of treatment.

Studies of this kind seek to identify which demographic, personal, psychological or neuropsychological factors make it more likely for an individual to benefit from a particular therapy delivered under particular settings.

Many studies have attempted to identify which factors predict successful outcome in CBTp (see Lincoln et al. (2014b) for a review). However, the picture emerging from these studies is far from consistent. Researchers have not agreed on a set of outcome measures which can be consistently applied, or which baseline predictors to validate.

Considering socio-demographic factors, some studies have found that younger patients benefit more in terms of positive symptoms (Morrison et al., 2012a, Thomas et al., 2011) and that higher educational attainment was shown to predict better outcome in negative symptoms (Allott et al., 2011).

The extent to which patients have insight into their symptoms, that they can attribute their symptoms to mental illness, and the influence of this insight on outcomes have also been examined. Higher insight at baseline predicted symptom improvement in two studies (Garety et al., 1997, Naeem et al., 2008) and Brabban et al. (2009) found that symptom reduction was associated with lower delusional conviction. Clinical factors have also shown to be predictive of therapy effectiveness. Lower baseline symptomology and, in particular, lower negative symptomology were shown to be related to more symptomatic improvement during CBTp (Tarrier Beckett et al., 1993).

Other potential predictor variables identified include; longer duration of untreated psychosis (Drury et al., 1996), greater self-reflectiveness (Perivoliotis et al., 2010), lower occupational functioning (Allott et al., 2011), and higher neuropsychological functioning (Premkumar et al., 2011).

The pattern of exploration of predictor variables of CBTp to date has largely been one of parallel, independent studies, each focusing on specific, often unique, predictors using similar but varying outcome measures. Study methodologies vary and contradictory findings are not uncommon. For example, Tarrier Beckett et al. (1993) found that lower baseline symptomology predicted greater outcome for CBTp, whereas Morrison et al. (2012b) found that more severe positive symptoms at baseline predicted better outcome.

To date there has not been an attempt to synthesise these findings using a systematic review. The timing of this current systematic review is important. International guidelines consistently recommend CBTp for patients with psychosis, yet CBTp is not as beneficial to some as to others. The more that is known about predictive factors, the better providers can target interventions towards patients more likely to benefit from treatment. Furthermore, by highlighting a population for whom CBTp is less effective, an informed re-evaluation of CBTp treatment modules would be possible, so that later versions of CBTp manuals would be more effective for a greater proportion of the population experiencing psychosis. Thus, the primary research question was: what baseline variables, if any, predict successful outcome in CBT for persons experiencing psychosis?

Section snippets

Literature research

A literature search was electronically conducted using CINAHL, Cochrane, EBSCO, EMBASE, ISI Web of Science, MEDLINE (Ovid), PsycARTICLES, PsycINFO, PubMed, and Scopus. No initial restrictions were placed on the year, or language of the studies.

Keywords used

The main search terms included “psychosis”, “psychotic disorder”, “cognitive behavioural therapy”, “cognitive behavioural therapy”, “cognitive therapy”, “randomised controlled trial”, “randomized controlled trial”, “predictor”, and “treatment outcome” in

Results

Study selection was undertaken by the first author (see p. 9, Fig. 1). 181 records were exported from 11 electronic databases. Forward and backward citation searches yielded 87 further records. Duplicates were removed and 222 records were searched by title. From these, 80 records contained no predictor variables and were excluded, 33 studies did not feature cognitive behavioural therapy, 56 did not use a population experiencing psychosis, and 42 records were excluded on the basis of

Age

Two studies suggest that older age of patient promotes better outcome from CBT. Haddock et al. (2006) in a study of 304 patients, found that older patients, over 21, did better in CBT, and that younger patients, under 21, responded better to counselling. In a related finding Kukla et al. (2014) with a sample of 50 participants, found that younger age of patient predicted poorer work engagement, and that older participants were more likely to stay longer in employment. Lincoln et al. (2014b)

Discussion

This current systematic review set out to examine the demographic, clinical and cognitive factors which may predict successful outcome in CBT with patients experiencing psychosis. The findings of this review suggest that it may be possible to identify factors which predict better response to cognitive behavioural interventions with adults experiencing psychosis. Many factors have shown predictive value in some studies but not in others. Other factors have been examined in only one study and

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