Cognitive approaches to delusions: a critical review of theories and evidence.

“Work on attentional biases in psychosis (Bentall and Kaney, 1989; Fear et al., 1996; Freeman et al., 2000) supports the concept of a data-gathering bias and a ‘jumping to conclusions’ style of reasoning in people holding paranoid delusional beliefs (Garety and Freeman, 1999).”

“].One of the central methods of CBT is precisely to encourage an observational and reflective stance towards aspects of self, including thought processes, behavioural patterns, and affective states. For example, the CBT therapist may assist the patient to identify paranoid cognitions and generate alternative explanati…”

“Other researchers opt for a multifactorial approach, allowing that delusions may be a function either of abnormal experience or of abnormal reasoning—or of both (cf. Garety & Freeman, 1999).”

“In a recent survey article Garety and Freeman point to the importance of evaluating reasoning relative to Bayesian norms, rather than in terms of the ability to grasp and manipulate the formal principles of deductive logic ( Garety and Freeman 1999 ).”

“characterized by deficits and biases in inferential thinking (Garety and Freeman, 1999; Coltheart et al., 2011; Balzan et al., 2013).”

“Several studies have found ToM deficits in individuals with schizophrenia (e.g., Corcoran et al., 1995; Garety and Freeman, 1999; Green et al., 2008), and this impairment has been shown to be associated with social functioning and social competence in schizophrenia (Roncone et al.”

“Garety and Freeman (1999) suggest thatthe jumptoconclusionsstyleofreasoning isnotafunction of a memory deficit.”

“At the same time, it has been proposed that patients refer success increasingly to themselves which, however, is less consistently reported (see Garety & Freeman, 1999 ).”

“In early research on cognitive processes in delusions (Bentall et al., 1994; Garety and Freeman, 1999), an externalising attributional bias and the JTC bias were considered crucial to the maladaptive appraisals in ‘ need for care ’ individuals, alongside personalising appraisals (Kinderman and…”

“The JTC bias refers to the tendency to reach a decision without gathering sufficient data (Garety et al., 1991; Garety and Freeman, 1999).”

“…that delusional beliefs cannot be explained without the role of additional, cognitive dysfunctions such as reasoning biases, or monitoring deficits that are necessary for the generation and maintenance of the false beliefs (e.g. Davies, Coltheart, Langdon, & Breen, 2001; Garety & Freeman, 1999).”

“The cognitive style that such studies implicate, characterised by the gathering of minimal data when making probabilistic judgements and also by relatively high confidence about those judgements once they are made, has come to be known as the “jumping to conclusions” bias (Garety & Freeman, 1999 ).”

“Contemporary theories converge in proposing that both perceptual and cognitive aberrations are crucial to the development of delusional beliefs (Garety & Freeman, 1999).”

“It has been widely shown that deluded individuals “jump to conclusions” on the basis of little information and are more confident in their decisions than nonpsychiatric control groups (e.g., Garety & Freeman, 1999; Garety, Hemsley, & Wessely, 1991; Huq, Garety, & Hemsley, 1988).”

“Interestingly, delusional patients ‘jump to conclusions’ in the first version, while they are more willing to revise their decision in light of contradictory evidence in the second (Garety and Freeman 1999).”

“…has been somewhat equivocal, with some studies showing exaggerated bias in the subset of patients with delusions (Martin and Penn, 2002; Combs et al., 2007) and others failing to show consistent bias in any subgroups (reviewed in Garety and Freeman, 1999; So et al., 2012; Menon et al., 2013).”

“There is a growing body of evidence demonstrating reasoning biases in people with delusions (Garety and Freeman, 1999).”

“This finding is contrary to Bentall and Kaney’s (1996) “weaker” formulation (Garety & Freeman, 1999, p. 137), but it is consistent with studies that have found low implicit SE in paranoia (McKay et al., 2007; Moritz et al., 2006).”

“Much of this work is focused specifically on delusional beliefs, and Garety and Freeman (1999) identify four explanatory models: delusions as explanations of unusual perceptual phenomena; delusions as a theory of mind deficit; delusions as a sign of problems with probabilistic reasoning; and…”

“, 2013] or an exaggerated selfserving bias in paranoid patients [Kaney and Bentall, 1989; Garety and Freeman, 1999]), whether those individuals with bipolar disorder and actively psychotic paranoid schizophrenia belong to this third group remains largely unexplored.”

“…schizophrenia are characterized by difficulties in information processing and reality testing (Brüne, 2005; Dudley, Taylor, Wickham, & Hutton, 2016; Garety & Freeman, 1999), which could impact their ability to fully distinguish between live interactions with a clinician (e.g., two-way video…”

“…reasoning in deluded patients has been questioned as a decision after, for example, two draws can only be considered rational if a participant knows that the likelihood of two yellow beads (see example before) originating from container A is 97% (Garety & Freeman, 1999; Ross et al., in press).”

“It is a topic of debate whether individuals with persecutory delusions have a discrepancy between overt and covert selfesteem (Freeman and Garety, 2004; Garety and Freeman, 1999).”

“Reviews in this field have highlighted four consistent dimensions: conviction (how strongly the belief is held); preoccupation (how often the belief is focused on); distress (whether the belief is linked to negative emotions, such as depression, anxiety, or anger); and action (whether the belief is linked to certain b…”

“Empirical studies found strong support for a reasoning bias (a tendency for people with delusions to gather less evidence than controls), and support for an attributional bias in people with paranoid delusions (Garety & Freeman, 1999).”

“…has demonstrated that Theory of Mind de fi cits in the schizophrenia spectrum are not explained by intelligence differences (Doody et al., 1998; Garety and Freeman, 1999; Mitchley et al., 1998; Pickup and Frith, 2001; Greig et al., 2004) but contribute to greater disability than psychosis…”

“This would support the theory that a jumping to conclusions reasoning bias may serve to maintain delusions (Garety and Freeman, 1999).”

“This is consistent with findings indicating that delusional individuals exhibit data-gathering biases in their reasoning processes and often jump to conclusions (Bentall, Kinderman, & Kaney, 1994 ; Garety & Freeman, 1999 ; Stone & Young, 1997 ).”

“…beads task has been used to test the hypothesis that deluded and delusion-prone individuals have a “jumping to conclusions” (JTC) data-gathering bias that results in them forming beliefs on the basis of less evidence than people who are not deluded or delusion-prone (Garety & Freeman, 1999, 2013).”

“Both biases have been implicated in delusion formation [16].”

“the jumping-to-conclusions (JTC) reasoning style, is thought to underlie delusional beliefs (Garety and Freeman, 1999).”

“…1994), difficulties in inferring others’ mental states (i.e. deficit on theory of mind, Frith, 1994), a preference for remembering material related to the theme of the delusion or data-gathering biases have all been found in deluded patients (reviewed in Garety & Freeman, 1999; Bentall, 2003).”

“Although the link between levels of self-esteem and attributional style is not conclusively established (Garety & Freeman, 1999), one result which is wellconfirmed by these studies is an externalising bias in subjects with persecutory delusions (Bentall, Kaney, & Dewey, 1991; Fear, Sharp, & Healey,…”

“Although a variety of studies have investigated the assumption that persecutory delusions are associated with abnormal attributions (Bentall, Corcoran, Howard, Blackwood, & Kinderman, 2001 ; Garety & Freeman, 1999 ), the recent evidence for an association between attributional biases and persecutory delusions is rathe…”

“In a widely used variant, they are permitted to request as many beads as they would like before making their guess (Garety & Freeman, 1999).”

“Commonly, JTC has been viewed as a specifi c contributor to delusion-maintenance and formation (Garety & Freeman, 1999).”

“…cognitive biases and errors responsible for the formation and maintenance of delusions (for reviews see Bell, Halligan, & Ellis, 2006; Freeman, 2007; Garety & Freeman, 1999), the specific processes responsible for the high conviction associated with delusional beliefs are less clearly understood.”

“This “jumping to conclusions” (JTC) bias, as it has come to be known, has been replicated in a series of subsequent studies and appears to be quite robust (Garety & Freeman, 1999 , for a review).”

“A new trend in psychotherapy for schizophrenia targets cognitive biases, such as jumping to conclusions (Freeman, 2007; Garety & Freeman, 1999) and overconfidence in errors (Moritz & Woodward, 2006; Moritz, Woodward, Jelinek, & Klinge, 2008), which are implicated in the formation and maintenance of…”

“Garety and Freeman (1999), however, have critiqued this interpretation of Kinderman’s results.”

“A review of attributional biases in schizophrenia has previously suggested that patients differ from controls on PB scores, but less frequently on EB scores (Garety and Freeman, 1999).”

“To summarize, a plethora of studies suggest that patients with schizophrenia are hastier in gathering information (for reviews, see Garety and Freeman, 1999, 2013; Fine et al., 2007) and are more confident in erroneous responses pertaining to memory (Moritz and Woodward, 2006a; Gaweda et al., 2012;…”

“Garety and Freeman (1999) on the other hand, from the review of cognitive processes of delusional thinking, found strong support for the notion that individuals with persecutory ideas in the face of setbacks are likely to jump to conclusions, display attributional bias, take things personally, and…”

“…examples of these reasoning biases, Stone and Young mention the jumping to conclusions (JTC) bias studied by Garety and colleagues (for reviews, see Garety and Freeman, 1999; Fine et al., 2007) and biased attributional style, particularly the 3 The word ‘doxastic’ means pertaining to belief or…”

“It has been proposed that low self-esteem is common in individuals with paranoia (Bentall et al., 2001; Garety and Freeman, 1999), and it has therefore been argued that self-esteem is a triggering factor in paranoia, especially since experience sampling studies have demonstrated that low selfesteem precedes the occurr…”

“Where the psychotic symptoms were often thought of as categories (normal vs. abnormal), the CBT-P clinician begins with the viewpoint that all beliefs/experiences fall on a continuum (Garety & Freeman, 1999).”

“…consistently replicated cognitive biases are the data gathering bias, characterised by ‘‘jumping to conclusions’’ on probabilistic reasoning tasks (see Garety & Freeman, 1999, for a review), and a bias against disconfirmatory evidence (BADE; Woodward, Moritz, & Chen, 2006; Woodward, Moritz,…”

“Individuals with schizophrenia a) jump to strong conclusions based on a small quantity of information;([13]) b) lack insight about their rashness and, thus, consider themselves indecisive;([14]) c) are unsure about their correct interpretations of information but over-confident about their incorrect interpretations of…”

“Impairments in these latter two domains, in particular, have been theorized to be related to the presence and severity of paranoid delusions (Garety and Freeman, 1999), and several researchers have examined this purported link (Bentall et al., 2009; Combs et al., 2009; Martin and Penn, 2002; Peer…”

“Jumping to conclusions is one of the most widely studied cognitive biases in psychosis (Freeman, 2007; Garety and Freeman, 1999; Moritz and Woodward, 2005) due to its higher prevalence in people with psychosis in comparison to healthy participants as found by So et al. (2016) in her meta-analyses…”

“Fear and anxiety, which are often neglected variables in delusion research (Freeman & Garety, 1999), are signi cant factors that sustain both types of episodes (see Lange & Houran, 1999;Wessely, 1987).”

“Nevertheless, the evidence for the first theory put forward by Bentall et al. (1994, 2001) which initiated the abundant research on self-esteem in patients with persecutory delusions has remained equivocal (Garety and Freeman, 1999; Freeman, 2007).”

“Garety and Freeman (1999) and Mujica-Parodi et al. (2000) reported that, on reasoning tasks, individuals with paranoid symptoms demonstrate a tendency to ‘‘jump to conclusions’’ (JTC), not seek counter examples, and make stronger judgments of certainty about their responses.”

“…of paranoia may help further our understanding of the social and information processing biases found in paranoia and assist in developing treatments specific for different types of paranoia (Chadwick & Trower, 1996; Combs, Michael, & Penn, 2006; Garety & Freeman, 1999; Martin & Penn, 2001).”

“The research base is equivocal, however, with studies of self-esteem yielding inconclusive results to date (see Garety and Freeman, 1999; MacKinnon, NewmanTaylor and Stopa, 2010; McKay, Langdon and Coltheart, 2007; Moritz, Werner and von Collani, 2006).”

“…e, David Fowler f, Elizabeth Kuipers a, Philippa Garety a a King's College London, Institute of Psychiatry, Department of Psychology, London, UK b School of Medicine, Health Policy and Practice, University of East Anglia, Norwich, UK c Division of Psychiatry, UCL, London, UK d Centre for…”

“Cognitive models also support the idea that negative affective states contribute to the maintenance of psychotic symptoms (Bentall et al., 2001; Freeman, 2007; Freeman et al., 2002; Garety et al., 2001; Garety and Freeman, 1999; Howes and Murray, 2014; Smith et al., 2006).”

“Earlier, we saw some versions of the two-factor account, according to which the second factor is a data-gathering bias (Garety & Freeman, 1999), the privileging of observational data (Stone & Young, 1997), or an inability to inhibit a pre-potent doxastic response (Davies et al., 2001).”

“This interpretation concurs with the clinically informed notions of delusions as beliefs arising from faulty interpretation of anomalous experiences (Garety & Freeman, 1999) and/or inadequate evidence (Coltheart et al., 2011; Irwin et al., 2012b).”

“Schizophrenia patients are known to have a jumping-to-conclusions reasoning style (Garety and Freeman, 1999; Garety et al., 2005) and poorer cognitive fl exibility (Ross et al., 2011).”