بدبینی، هذیان های آزاردهنده و جهت گیری های اسنادی

An influential model of persecutory delusions put forward by Bentall and colleagues hypothesizes that persecutory-deluded patients avoid the activation of negative self-beliefs by making externalising, personalising attributions for negative events. The first study reported here used a new instrument for the measurement of persecutory ideation, the Paranoid, Persecutory and Delusion-Proneness Questionnaire, to investigate whether attributional biases are associated with subclinical persecutory ideation. The second study extended this investigation by re-examining associations between attributional biases and persecutory delusions. Both studies used the Internal, Personal and Situational Attributions Questionnaire to measure attributional style. No evidence was found for a connection between attributional biases and subclinical persecutory ideation. Furthermore, there was no support for an association between persecutory delusions and an externalising bias, and only marginal support for the hypothesized relationship between persecutory delusions and a personalising bias. These results suggest that the putative link between persecutory ideation and attributional biases only manifests (if at all) when persecutory ideation is of delusional intensity, and that it is confined to a personalising bias.

Bentall and colleagues (e.g., Bentall et al., 1994, Bentall and Kaney, 1996, Kinderman and Bentall, 1996b and Kinderman and Bentall, 1997) are influential advocates of a psychodynamically inflected model of persecutory delusions. These authors assume that patients with persecutory delusions harbour latent negative self-beliefs that are susceptible to activation by negative life events. In this respect, persecutory-deluded patients are thought to be similar to depressed patients. Unlike depressed patients, however, patients with persecutory delusions are hypothesised to defend against the activation of negative self-beliefs by attributing negative events to the actions of other agents. Through such external–personalising attributions, individuals with persecutory delusions maintain their overt self-esteem by effectively projecting their latent negative self-representations onto others. The ensuing cost of maintaining self-esteem in this way, however, is that such individuals must live in a subjective world that is peopled with hostile, malevolent beings. A variety of studies have investigated the notion that persecutory delusions are associated with abnormal attributions (for reviews, see Garety and Freeman, 1999 and Bentall et al., 2001). The research findings are somewhat equivocal, with some studies (e.g., Kaney and Bentall, 1989 and Kaney and Bentall, 1992) suggesting that people with persecutory delusions display an exaggeration of the normal self-serving bias, attributing positive events excessively to internal causes and negative events excessively to external causes. Other studies (e.g., Lyon et al., 1994) have replicated only the latter part of this pattern (external attributions for negative outcomes), implying that persecutory-deluded patients do not differ from non-clinical control participants in taking excessive credit for positive events. Kinderman and Bentall (1997) found that persecutory delusions were associated not so much with a tendency to make external (as opposed to internal) attributions for negative events as with a tendency to make external–personal (as opposed to external–situational) attributions for these events. Garety and Freeman (1999) conclude that the attributional bias in persecutory delusions is thus most likely a personalising bias: a tendency to blame others for negative events. Given that the model of Bentall and colleagues pertains specifically to persecutory delusions, it is important to ascertain whether the attributional abnormalities involved are specific to delusions with persecutory content, or whether they are associated with all delusions, irrespective of delusional theme. A study by Sharp et al. (1997) investigated this question by comparing different delusional subtypes in patients with delusional disorder. Their findings were that excessively external attributions for negative events were specific to persecutory and grandiose delusions. Other delusional themes (e.g., somatic delusions, delusional jealousy) were not associated with this bias. Sharp et al. (1997) suggest that attributional abnormalities are not involved in the genesis of delusions, per se, but that they may play a role in shaping the thematic content of delusions. The results of Sharp et al. (1997) suggest that attributional biases do not have a primary aetiological role in the genesis of delusions generally, but rather that they may be associated with ideation that is thematically specific—namely, persecutory (and grandiose) ideation. This suggestion raises the possibility that attributional biases may be associated with persecutory ideation in non-clinical populations. This hypothesis involves a dimensional approach to persecutory beliefs, in contrast to the traditional categorical approach of psychiatry. Dimensional models of psychosis-proneness conceptualise clinical symptoms in patients as extreme expressions of personality traits found within the normal adult population. Such approaches therefore provide a means of testing models of clinical symptoms using samples of non-clinical individuals, thus avoiding many potential confounds inherent in work with clinical patients (e.g., medication and institutionalisation; Claridge, 1994). Martin and Penn (2001) examined the linear relationship between subclinical paranoid ideation and attributional style, as well as other clinical and social cognitive variables. The Paranoia Scale (Fenigstein and Vanable, 1992), the Internal, Personal and Situational Attributions Questionnaire (IPSAQ; Kinderman and Bentall, 1996a), and a variety of other measures were administered to 193 undergraduates. Paranoid ideation was not associated with any particular attributional style, whether externalising or personalising. As Martin and Penn (2001) acknowledge, however, their study is limited in that it used a measure of general paranoid ideation (the Paranoia Scale) rather than persecutory ideation specifically. It may be that the attributional biases implicated in persecutory delusions are associated with persecutory ideation specifically, whereas the Paranoia Scale might be assessing other components of paranoia (e.g., ideas of reference) in addition to persecutory ideation. The findings of the study of Sharp et al. (1997) are consistent with the notion that an externalising attributional bias might be associated with persecutory ideation specifically rather than paranoid ideation generally. Sharp et al. found that an externalising bias for negative events was associated with persecutory delusions but not with morbid jealousy (a delusion that is paranoid but not persecutory).1 Moreover, many items on the Paranoia Scale pertain to past incidences of harm rather than present or future harm and so do not conform to the comprehensive criteria for persecutory beliefs set out by Freeman and Garety (2000). Martin and Penn (2001) suggest that their study be repeated using a measure of subclinical paranoia more suitable for assessing specifically persecutory ideation. The first of the two experiments reported here was designed to do just that by using a newly developed questionnaire, the Paranoid, Persecutory and Delusion-Proneness Questionnaire (PPDQ; McKay, 2004). The PPDQ was designed to tease out distinctions between the constructs of paranoid ideation, persecutory ideation and delusionality. This questionnaire avoids conflating persecution with other components of paranoia and comprises the following three valid and internally consistent subscales: Persecutory Paranoid Ideation, Non-Persecutory Paranoid Ideation and Non-Paranoid Delusion-Proneness. If externalising and personalising biases are associated with ideation that is specifically persecutory (irrespective of delusional intensity), then positive correlations would be expected between indices of these two types of attributional bias and the Persecutory Paranoid Ideation Index.

The studies reported here were designed to investigate the role of attributional biases in both subclinical and clinical persecutory ideation. Consistent with Martin and Penn (2001), we did not find any evidence in our first study of an association between attributional biases and subclinical persecutory ideation. One possible implication of this result is that the dimensional approach to investigating the role of attributional biases in persecutory delusions is limited. The results of our second study, however, are consistent with those of Martin and Penn (2002) in that they provide only tenuous support for the hypothesized link between full-blown persecutory delusions and attributional biases. We suggest, therefore, that the failure to find an association between attributional style and subclinical persecutory ideation does not undermine the assumption of dimensionality with respect to persecutory symptoms, but rather reflects the fact that the connection between acute persecutory ideation and attributional style is itself weak. An effect that is difficult to detect in a clinical population will naturally be even more difficult to detect in a subclinical population, dimensionality assumptions notwithstanding. In conclusion, the present study found no support for an association between persecutory delusions and a self-serving/externalising bias, and only very limited support for an association between persecutory delusions and a personalising bias. No evidence was found for an association between attributional biases and subclinical persecutory ideation. These results suggest that the link between persecutory ideation and attributional biases is rather weak, appearing only when persecutory ideation is of sufficient intensity and (as per Kinderman and Bentall, 1997) being confined to a personalising bias.