Persecutory delusions and catastrophic worry in psychosis: Developing the understanding of delusion distress and persistence

Abstract

In a recent theoretical account of persecutory delusions, it is suggested that anxiety and worry are important factors in paranoid experience [Freeman, D., Garety, P. A., Kuipers, E., Fowler, D., & Bebbington, P. E. (2002). A cognitive model of persecutory delusions. British Journal of Clinical Psychology, 41(4), 331–347]. In emotional disorders worry has been understood in terms of catastrophising. In the current study, the concept of catastrophising is applied for the first time with persecutory delusions. Thirty individuals with current persecutory delusions and 30 non-clinical controls participated in a cross-sectional study. The group with persecutory delusions was also followed up at 3 months to assess predictors of delusion persistence. At its most severe, 21% of individuals with persecutory delusions had clinical worry, 68% had levels of worry comparable with treatment seeking GAD patients. Further, high levels of anxiety, worry and catastrophising were associated with high levels of persecutory delusion distress and with the persistence of delusions over 3 months. If future research replicates these findings, worry reduction interventions for individuals with persecutory delusions may be warranted.

Introduction

In the last 10 years, advancements have been made in our understanding of cognitive and behavioural factors relevant to delusions and this has been accompanied by advancements in psychological treatment (e.g. Sensky et al., 2000). Nonetheless, at least one-third of individuals with persistent positive symptoms do not demonstrate measurable benefit from interventions such as cognitive behavioural therapy (CBT) and remain distressed by symptoms (Kuipers et al., 1998). One route to improving treatment interventions is to further our understanding of pathways that lead to delusion distress and persistence. In the current study, we focus upon understanding the contribution of anxiety to the experience of persecutory delusions.

Anxiety is known to be present at all stages of delusion formation and maintenance (cf. Freeman, Garety, Kuipers, Fowler, & Bebbington, 2002). Mueser et al. (1998) report that levels of anxiety are high in many years before the development of psychosis. Further, prospective, retrospective and clinical studies find that in a majority of cases (60–80%), symptoms of anxiety, depression and irritability precede by 2–4 weeks the appearance of positive symptoms, often accompanied by subtle cognitive changes and later, by low-level psychotic phenomena (Birchwood, Macmillan, & Smith, 1992; Docherty, Van Kammen, Siris, & Marder, 1978). There is also a high comorbidity of anxiety disorders and psychosis. Cosoff and Hafner (1998) report that 43% of 60 consecutive inpatients with schizophrenia have an anxiety disorder. Thus, anxiety has the potential to play a role at all stages of persecutory belief formation.

The importance of anxiety to the delusional experience is highlighted in a recent theoretical model of persecutory delusions (Freeman et al., 2002). For instance, anxiety is considered to provide the threat theme integral to a persecutory delusion; anxiety and worry processes are hypothesised to lead to delusional thoughts becoming distressing; and anxiety related processes such as worry and safety behaviours are hypothesised to contribute to delusion persistence. One study of delusions is of particular interest here. Freeman and Garety (1999) compared individuals with persecutory delusions and individuals with Generalized Anxiety Disorder (GAD) on measures of anxiety, worry and meta-worry. It was found that (i) both the tendency to worry and the frequency of general worry for the persecutory delusions group were comparable with that found in the anxious group and (ii) many patients with persecutory delusions endorsed meta worry items (such as ‘I worry that I cannot control the thoughts about the belief’) and the presence of such meta-worry and trait anxiety were strongly correlated with delusion distress. This study provides the first empirical evidence that worry may be important to the delusional experience.

It is argued that worry in delusions can be understood in terms of the same processes as worry in anxiety disorders. The focus here is on catastrophic worry specifically (for a review of general theories of worry, see Davey & Wells, 1996). Worry by individuals with persecutory delusions may be understood by the process of catastrophising known to drive worry in GAD (Davey & Levy, 1998; Startup & Davey, 2001; Vasey & Borkovec, 1992). Catastrophising occurs when individuals persistently iterate the problematic features of their worry topic. However, rather than bringing the worry problem to a satisfactory close, catastrophising leads to the worrier perceiving progressively worse outcomes to the worry topic. It is often characterized as the worrier posing internal, automatic questions of the “what if…?” kind (Kendall & Ingram, 1987). Recent studies of perseverative catastrophising have utilised an experimental interview procedure based on the cognitive therapy technique of decatastrophising (Kendall & Ingram, 1987). This interview procedure invites the participant to iterate successive steps in the catastrophising process, providing a quantative assessment of catastrophic worry (i.e. the number of catastrophising steps generated). The interview begins with the experimenter asking the question “What is it that worries you about (X)?” where X is traditionally the participant's current main worry. The experimenter then repeats this question but substituting the participant's answer to the first question for X. For example, if the individual's worry topic is—arguments with my partner, the first question will be “what is it that worries you about arguments with your partner?” If the participant replies, “that she might leave me”, the experimenter then asks “what is it that worries you about your partner leaving you?” and so on. The catastrophising interview is terminated when participants report that they can think of no more responses.

Studies have consistently found that worriers generate significantly more catastrophising steps than non-worriers, report a significant increase in subjective discomfort as catastrophising unfolds, and rate events in the catastrophising sequence as significantly more likely to occur than non-worriers (Davey & Levy, 1998; Startup & Davey (2001), Startup & Davey (2003); Vasey & Borkovec, 1992). Moreover, similar relationships have been replicated for individuals meeting criteria for GAD (Hazlett-Stevens & Craske, 2003). Davey and Levy (1998) have found that worriers will not only iterate over negative material to a greater degree than non-worriers but that they will iterate over positive material to a greater degree too. They thus suggest that worriers may have a ‘general perseverative iterative’ cognitive style that operates independently of the valence of the iterative material. In order to explore such hypotheses a ‘reverse’ catastrophising interview procedure is used, which is identical in format to the catastrophising interview but invites participants to iterate steps for a positively valanced hypothetical scenario (such as why it would be a good thing to be a weather forecaster cf. Davey & Levy, 1998).

The current research is designed to test the paranoia model predictions of a role for worry in delusional experience (Freeman et al., 2002). A key process characteristic of worry-catastrophising—is explored within a population of individuals with persecutory delusions. In addition a ‘reverse’ catastrophising procedure is employed to explore the predictions of Davey and Levy (1998). Following Freeman and Garety (1999), associations between catastrophic worry and the dimensions of the delusional experience are then considered. The relationships between worry and delusional persistence will also be explored at 3-month follow-up. Based upon our literature review, the following hypotheses are tested:

• The majority of individuals with persecutory delusions will have high levels of anxiety and worry compared with a non-clinical control group.

• In individuals with persecutory delusions, worry will be associated with a greater number of catastrophising steps in the catastrophising interview.

• In individuals with persecutory delusions worry will also be associated with greater ‘reverse’ catastrophising.

• Anxiety and worry will be associated with increased severity and likelihood ratings for catastrophic outcomes.

• Anxiety and worry will be associated with levels of delusional distress.

• Anxiety and worry will be associated with less recovery in delusions over 3 months (i.e. delusion persistence).