طرح واره خودکشی در روان پریشی غیر عاطفی: بررسی تجربی

Suicide is the leading cause of premature death among individuals experiencing psychosis. The risk of suicide is proposed to increase with a greater potential for activation of suicide related schemas. Empirical representations of suicide schemas were compared between individuals experiencing non-affective psychosis, with and without a history of suicidal behaviour. Employing a cross-sectional between-groups comparison design, 84 participants, previously diagnosed with a non-affective psychotic disorder, were recruited from community mental health services. Participants completed a demographic questionnaire and clinical measures of psychopathology. To assess participants’ suicide schemas, a series of direct and indirect cognitive tasks were designed and administered. Pathfinder analysis enabled the construction of empirically derived representations of the groups’ suicide schemas based on responses to the cognitive tasks. The suicide group achieved significantly greater scores on measures of anxiety, depression, hopelessness and suicidality than the non-suicide group, but not on measures indicative of the severity of psychosis. The suicide schema for the suicide group was more elaborate and extensive than for the non-suicide group, even when clinical measures were taken into account. Clinical and theoretical implications are discussed.

Suicide is the leading cause of premature death among individuals experiencing psychosis with the rate of suicide ranging from 147 to 750 per 100,000 persons per year (Heila et al., 1997 and Palmer et al., 2005). Approximately 40% of patients diagnosed with schizophrenia report suicidal ideation (Tarrier, Barrowclough, Andrews, & Gregg, 2004), 20–40% make at least one suicide attempt during the illness phase and 5–13% end their lives by suicide (Barraclough et al., 1974 and Harris and Barraclough, 1997). The lifetime risk of completing suicide is estimated to be 20–50 times higher than in the general population (Caldwell & Gottesman, 1992). An established literature now exists describing factors reliably shown to be associated with an increased risk of suicide among people experiencing psychosis, including previous suicide attempts and comorbid mental health problems (Hawton et al., 2005, Hu et al., 1991 and Roy and Draper, 1995). The identification of such risk factors is a major strategy for predicting and preventing suicide (Tatarelli, Pompili, & Girardi, 2006). However, it remains a much more difficult task to prospectively evaluate which individual will eventually complete suicide (Bolton, Gooding, Kapur, Barrowclough, & Tarrier, 2007). In order to develop viable psychological interventions for suicide in psychosis, a better understanding is required of the underlying mechanisms. However, there are few well-articulated, theoretically driven and empirically tested models to explain suicidal behaviour in general (O’Connor & Sheehy, 2000) and in psychosis, in particular (Bolton et al., 2007). One theoretical model that attempts to explain suicidal behaviour is the Cry of Pain model (Williams, 1997). In brief, events, either directly or indirectly related to psychosis, can present as the necessary stressors for suicide risk. Specifically, situations of social rejections, failure to achieve valued roles or negative self-evaluation may be appraised in terms of defeat. Information processing biases, a negative schema and problem-solving deficits may influence appraisals such that inflexible negative perceptions of the self or negative responses to others become more likely. Positive, constructive exits or escape routes subsequently become limited. This process then elevates a felt sense of pessimism, worthlessness, and helplessness resulting in intractable feelings of entrapment. A real or perceived absence of rescue factors, in the form of social support resources that are available and important, accentuate the effects of this process. Finally, the ‘Cry of Pain’ can only be acted upon in the presence of imitation models and access to available means. Williams’ (1997) Cry of Pain model supports a common multi-factor mechanism approach and, as such, should be equally applicable to a range of mental disorders. In recognition of the strengths and limitations of this model, we have developed the Schematic Appraisal Model of Suicide (SAMS; Johnson, Gooding, & Tarrier, 2008). The SAMS model extends the focus upon concepts of defeat, entrapment and ‘no rescue’ by specifying the key underlying cognitive and behavioural processes associated with suicidal behaviour. Negative information processing biases are thought to feed into a semantic memory system or ‘suicide schema’ and a multi-stage appraisal system (current, historical, future, self, agency). These latter two systems interact and determine goal directed escape behaviour towards suicide. Our empirical research so far has supported the SAMS model (Johnson et al., 2008, Tarrier et al., 2007 and Taylor et al., 2009). The ‘suicide schema’ can be seen as an example of a semantic network of interconnecting stimulus, response and emotional stored information pertaining to suicide. When activated, this schema will trigger thoughts of suicidal behaviour as an escape strategy from an intolerable emotional or situational state (Bower, 1981). According to spreading activation theories, each time the suicide schema is activated, it becomes strengthened and embellished as it incorporates further cognitive, emotional or stimulus elements, such as experiential psychotic symptoms and associated emotional, cognitive states or consequences (Teasdale, 1988). The more extensive and elaborate the suicide schema becomes, the greater its potential to be re-activated and subsequently even more refined, persistently adding to the individual’s risk of eventual suicide. Repeated activation of the schema will lead to associations with a wider range of mood states and contexts; thus increasing the risk of suicidal behaviour in the future (Williams, Crane, Barnhofer, & Duggan, 2005). It is expected that suicide schemas will vary from individual to individual, since the differential activation model suggests that people differ in the ease with which small changes in mood can reactivate particular networks of self-referent, negative thoughts (Williams et al., 2005). However, Rudd, Joiner, and Rajab (2001) hypothesised consistency across individuals in terms of categories or themes comprising the suicide schemas. Whilst the conceptual notion of schemas has been intuitively appealing since it was introduced into clinical applications by Beck (1967), empirical descriptions of individuals’ actual schemas are rare in the literature. The main aim of the current study was to construct an empirical representation of a suicide schema typical of individuals with psychosis and a history of suicidal behaviour (suicide group) and to compare that suicide schema with a suicide schema typical of individuals with psychosis but with no previous suicidal behaviour (non-suicide group). People with a history of suicidal behaviour are predicted to have activated their suicide schema more often than people without such a history (Lau, Segal, & Williams, 2004). Therefore, the suicide schema generated by the suicide group was hypothesised to be more extensive and elaborate, compared to the non-suicide group. Since the current study was exploratory in nature, two additional investigations were conducted to examine potential alternative explanations to any differences found between the suicide and non-suicide groups. To investigate the potential influence of psychopathology on suicide schemas (Hawton et al., 2005), the current study examined whether differences in the groups’ suicide schemas could be explained by measures of psychopathology. A second exploratory hypothesis suggested the suicide schema generated for individuals with histories of multiple suicide attempts would be more extensive and elaborate than the suicide schema for individuals with one or no previous suicide attempts (Hu et al., 1991 and Roy and Draper, 1995).