Biomedical subjects

Daniel Freeman

Publications and source records attributed to Daniel Freeman.

At least 19 recordsLinked to original sources

PubMed2006

Slow habituation of arousal associated with psychosis proneness.

BACKGROUND: Previous studies report skin conductance (SC) abnormalities in both patients with schizophrenia and psychosis-prone individuals. However, no studies have assessed SC abnormalities in relation to specific psychotic and emotional symptoms. The aim of the present study was to examine the relationship between SC orienting response and hallucination proneness, delusional ideation, anxiety and self-focused attention in non-clinical individuals. METHOD: Forty-three participants were recruited and divided into two groups depending upon the SC habituation profile. Normal habituators (n=28) and slow habituators (n=15) were compared on measures of psychosis proneness, anxiety and self-focused attention. RESULTS: Slow habituators had significantly higher levels of delusional ideation and hallucination proneness than the normal habituators. SC habituation scores were particularly associated with the conviction of delusional ideas. Levels of anxiety or self-focused attention did not differ significantly between the groups. CONCLUSIONS: The study provides evidence of 'aetiological continuity'. Common mechanisms may contribute to psychotic experiences in non-clinical and clinical samples, consistent with the notion of a psychosis continuum.

Adolescent↗

PubMed2006

Cognitive, emotional, and social processes in psychosis: refining cognitive behavioral therapy for persistent positive symptoms.

Psychosis used to be thought of as essentially a biological condition unamenable to psychological interventions. However, more recent research has shown that positive symptoms such as delusions and hallucinations are on a continuum with normality and therefore might also be susceptible to adaptations of the cognitive behavioral therapies found useful for anxiety and depression. In the context of a model of cognitive, emotional, and social processes in psychosis, the latest evidence for the putative psychological mechanisms that elicit and maintain symptoms is reviewed. There is now good support for emotional processes in psychosis, for the role of cognitive processes including reasoning biases, for the central role of appraisal, and for the effects of the social environment, including stress and trauma. We have also used virtual environments to test our hypotheses. These developments have improved our understanding of symptom dimensions such as distress and conviction and also provide a rationale for interventions, which have some evidence of efficacy. Therapeutic approaches are described as follows: a collaborative therapeutic relationship, managing dysphoria, helping service users reappraise their beliefs to reduce distress, working on negative schemas, managing and reducing stressful environments if possible, compensating for reasoning biases by using disconfirmation strategies, and considering the full range of evidence in order to reduce high conviction. Theoretical ideas supported by experimental evidence can inform the development of cognitive behavior therapy for persistent positive symptoms of psychosis.

Affect↗

PubMed2006

Emotion and psychosis: links between depression, self-esteem, negative schematic beliefs and delusions and hallucinations.

BACKGROUND: The role of emotion in psychosis is being increasingly recognised. Cognitive conceptualisations of psychosis (e.g. [Garety, P.A., Kuipers, E.K., Fowler, D., Freeman, D., Bebbington, P.E., 2001. A cognitive model of the positive symptoms of psychosis. Psychological Medicine, 31, 189-195]) emphasise a central, normal, direct and non-defensive role for negative emotion in the development and maintenance of psychosis. This study tests specific predictions made by Garety et al. [Garety, P.A., Kuipers, E.K., Fowler, D., Freeman, D., Bebbington, P.E., 2001. A cognitive model of the positive symptoms of psychosis. Psychological Medicine, 31, 189-195] about the role of emotion and negative evaluative beliefs in psychosis. METHODS: 100 participants who had suffered a recent relapse in psychosis were recruited at baseline for the Prevention of Relapse in Psychosis (PRP) trial. In a cross-sectional analysis, we examined the role of depression, self-esteem and negative evaluative beliefs in relation to specific positive symptoms (persecutory delusions, auditory hallucinations and grandiose delusions) and symptom dimensions (e.g. distress, negative content, pre-occupation and conviction). RESULTS: Analysis indicated that individuals with more depression and lower self-esteem had auditory hallucinations of greater severity and more intensely negative content, and were more distressed by them. In addition, individuals with more depression, lower self-esteem and more negative evaluations about themselves and others had persecutory delusions of greater severity and were more pre-occupied and distressed by them. The severity of grandiose delusions was related inversely to depression scores and negative evaluations about self, and directly to higher self-esteem. CONCLUSIONS: This study provides evidence for the role of emotion in schizophrenia spectrum-disorders. Mood, self-esteem and negative evaluative beliefs should be considered when conceptualising psychosis and designing interventions.

Adolescent↗

PubMed2006

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

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.

Adult↗

PubMed2006

A validation of a new measure of activity in psychosis.

Despite demonstrated relationships between activity and clinical change, we lack effective measures of time use in psychosis. Existing time budget measures of activity are demanding to complete, and thus unsuited to routine clinical use as measures of change. Less burdensome 'check-box' measures are prone to bias and omission in the activities selected. We recently devised a simplified time budget measure of activity in psychosis which was piloted on a small sample [Jolly, S., Garety, P., Dunn, G., White, J., Aitken, M., Challocombe, F., Griggs, M., Wallace, M., Craig, T. 2005. A pilot validation study of a new measure of activity in psychosis. Soc. Psychiatry Psychiatr. Epidemiol. 40, 905-911]. This study is a larger scale validation. 276 participants with a recent relapse of non-affective psychosis completed the new time budget, together with an established measure of global social functioning, measures of positive and negative psychotic symptoms, positive symptom distress and affect. The time budget measure showed a correlation of 0.5 with both the SOFAS and the SANS avolition/apathy subscale. Activity levels were related to psychotic symptomatology, both positive and negative. Positive symptom distress was more strongly associated with activity levels than symptom severity and affective disturbance. We conclude that the time budget measure can be used as an indicator of social functioning, with potential as a measure of therapeutic change. We are currently investigating its sensitivity in this context.

Adult↗

PubMed2006

The Brief Core Schema Scales (BCSS): psychometric properties and associations with paranoia and grandiosity in non-clinical and psychosis samples.

BACKGROUND: Traditional instruments that measure self-esteem may not relate directly to the schema construct as outlined in recent cognitive models. The Brief Core Schema Scales (BCSS) aim to provide a theoretically coherent self-report assessment of schemata concerning self and others in psychosis. The scales assess four dimensions of self and other evaluation: negative-self, positive-self, negative-other, positive-other. METHOD: We analysed the psychometric properties of the BCSS using a sample of 754 students recruited by email and 252 people with psychosis recruited as part of a trial of cognitive therapy. We report the internal consistency, stability and the factor structure of the scale, and the association of the BCSS with measures of self-esteem and with symptoms of paranoia and grandiosity. RESULTS: The BCSS have good psychometric properties and have more independence from mood than the Rosenberg Self-Esteem Schedule. People with chronic psychosis reported extreme negative evaluations of both self and others on these scales, but their levels of self-esteem and positive evaluations of self and others were similar to the student sample. CONCLUSIONS: Extreme negative evaluations of self and others appear to be characteristic of the appraisals of people with chronic psychosis, and are associated with symptoms of grandiosity and paranoia in the non-clinical population. The BCSS may provide a more useful measure of schemata about self and others than traditional measures of self-esteem.

Adult↗

PubMed2006

Misattribution of self-generated speech in relation to hallucinatory proneness and delusional ideation in healthy volunteers.

When patients with hallucinations and delusions encounter their own distorted speech they tend to mistakenly attribute it to someone else. This external misattribution of self-generated material is thought to be associated with 'positive' psychotic symptoms. The aim of the present study was to examine this process in relation to the predisposition to hallucination-like experiences and unusual beliefs in a healthy population. Fifty-seven volunteers completed assessments of hallucination proneness and delusional ideation and performed a source-monitoring task. Participants listened to a series of pre-recorded words for which the source (self/non-self) and acoustic quality (undistorted/distorted) of the speech were varied across trials. Participants indicated whether the words were spoken in their own or another person's voice via a button press. Misattribution errors were greatest when participants made source judgements about their own distorted speech (p < 0.01) and were positively correlated with delusional ideation scores, particularly the level of conviction with which delusional ideas were held (p = 0.03), and there was a trend for a positive correlation with hallucination proneness scores. There was a negative correlation between unsure responses and delusional ideation when participants were processing their own distorted speech (p = -0.03). The misattribution of self-generated speech occurs in healthy individuals with high levels of psychotic-like experiences. This suggests that the same cognitive impairments may underlie psychotic phenomena in healthy individuals as in patients with psychotic disorders, consistent with a continuum model of psychosis.

Adolescent↗

PubMed2006

Acting on persecutory delusions: the importance of safety seeking.

OBJECTIVE: Acting on delusions is a significant clinical issue. The concept of safety behaviours--actions carried out with the intention of reducing perceived threat--provides a new way of understanding acting on delusions. A study was conducted with the aim of examining the prevalence and correlates of safety behaviours related to persecutory delusions. METHOD: One hundred patients with persecutory delusions were assessed for safety behaviours, acting on delusions, anxiety, depression, and psychotic symptoms. Case note data were collected on instances of serious violence or suicide attempts. RESULTS: Ninety-six patients had used safety behaviours in the last month. Greater use of safety behaviours was associated with higher levels of distress. A history of violence or suicide attempts was associated with greater use of safety behaviours. Safety behaviours were significantly associated with acting on delusions, but not with the negative symptoms of psychosis. CONCLUSION: Safety behaviours are a common form of acting on persecutory delusions. These behaviours have the consequence that they are likely to prevent the processing of disconfirmatory evidence and will therefore contribute to delusion persistence.

Adolescent↗

PubMed2006

Attributional style in psychosis--the role of affect and belief type.

People holding persecutory beliefs have been hypothesised to show a self-serving attributional style, which functions to protect self-esteem Bentall, Corcoran, Howard, Blackwood, and Kinderman (2001). Experimental support for this has been mixed. Freeman et al. (1998) suggested depressed and grandiose subgroups of those with persecutory beliefs might explain events differently. In this study, 71 participants completed measures of delusional beliefs, depression and attributional style. We hypothesised that those with persecutory beliefs would form grandiose and depressed subgroups, and that a self-serving attributional style would characterise only the grandiose subgroup. Hypotheses were partially confirmed. Clear subgroups were evident and only those with both persecutory and grandiose beliefs showed an externalising attributional style for negative events. Depression, irrespective of co-occurring persecutory beliefs, was related to a reduced self-serving bias and an externalising attributional style for positive events. On their own, persecutory beliefs were not related to any particular attributional style. Depressed and grandiose subgroups of those with persecutory beliefs might account for some of the inconsistencies in the attribution literature. Even within a single symptom group, care should be taken in both research and therapy to consider individual symptom patterns.

Adaptation, Psychological↗

PubMed2006

Identifying potential predictors of traumatic reactions to psychotic episodes.

OBJECTIVES: The experience of a psychotic episode can sometimes lead to post-traumatic stress disorder (PTSD) symptoms. The objective of the research was to identify candidate predictors of such negative reactions for future prospective study. We examined six predictors identified from the PTSD and psychosis literatures in a retrospective study: a history of previous trauma, a history of previous episodes of psychosis, perceived helplessness and uncontrollability at the time of the index psychotic episode, the content of persecutory delusions at episode and the perceived presence of crisis support after the psychotic episode. DESIGN: The design was a cross-sectional self-report and interview study of people with recently remitted symptoms of psychosis. METHOD: 36 individuals with delusions and hallucinations that had remitted in the past year were assessed for the presence of PTSD symptoms in reaction to their most recent psychotic episode. Measures of the potential predictors were also taken at this point and associations with PTSD symptoms tested. RESULTS: 61% of the individuals with remitted positive symptoms had a reaction to their psychotic episode that was potentially severe enough to receive a PTSD diagnosis. Higher levels of PTSD symptoms were associated with all six predictors tested. CONCLUSIONS: The study provides further evidence that negative reactions to psychotic episodes are relatively common. Clinicians may wish to assess for such symptoms. The study extended these findings by identifying a number of candidate psychological predictors of PTSD reactions such as perceptions of uncontrollability and absence of support. Prospective longitudinal studies are required to test the causal significance of these factors. More broadly, the findings indicate that traumatic stress in response to intra-psychic events such as delusions can be understood in similar ways to traumatic stress arising from physical traumas such as disasters.

Adult↗

PubMed2006

Content and affect in persecutory delusions.

OBJECTIVES: The study aimed to explore the content of persecutory delusions and its potential links with levels of affective disturbance. Detailed examinations of the phenomenology of delusional beliefs have been rare, but are important for furthering theoretical and clinical understanding. DESIGN: A cross-sectional investigation of 70 individuals with current persecutory delusions was conducted. METHODS: Taped semi-structured clinical interviews were transcribed for each participant. Using a coding frame devised for the current study, a detailed description of persecutory content was made. Scores on the Beck Depression and Anxiety Inventories, the Rosenberg Self-esteem Scale and the Psychotic Symptom Rating Scales were used as indicators of emotional distress. RESULTS: Data were gathered on the identity and type of persecutor, pervasiveness of threat and the power of the persecutor. Reliability was good. Beliefs involving multiple persecutors, human in nature and identifiable to the individual were common. For the majority threat was severe, ongoing and enduring and coupled with frequent feelings of vulnerability. Specific aspects of delusional content were found to be associated with emotional distress. For example, if participants felt more power in the face of persecution this was coupled with lower depression and higher self-esteem. CONCLUSIONS: Persecutory delusions are beliefs concerning severe threat, particularly of physical harm including death, which is personally significant, frequently involving multiple persecutors known to the individual. Depression is higher in those who felt less powerful than their persecutors. Associations, such as this, with emotional distress support a direct role for emotion in delusion formation and maintenance. It is consistent with cognitive models of delusions which emphasize the importance of considering emotional distress in the context of belief appraisal, although interpretation of the results is limited by the cross-sectional study design. Recognizing these links may in turn aid therapists in identifying aspects of beliefs that might be targeted to facilitate emotional change.

Adolescent↗

PubMed2005

Genes required for fructose metabolism are expressed in Purkinje cells in the cerebellum.

Since 1967, fructose has become the primary commercial sweetener in the food industry. Large amounts of fructose can be toxic and have been correlated with atherosclerosis, malabsorption, hyperuricemia, lactic acidosis, and cataracts. To understand the deleterious and critical role(s) fructose plays in normal metabolism, it is essential to know how and where fructose is metabolized. The fructose transporter, GLUT5, and the specialized enzymes ketohexokinase, aldolase, and triokinase comprise the well-defined fructose-specific metabolic pathway found in liver, kidney, and small intestine. It is estimated that 50-70% of ingested fructose is metabolized in these tissues; where and how the remaining 30-50% is metabolized is not well defined. Prediction of tissues capable of metabolizing fructose via this pathway was done using expressed sequence tags (ESTs) in Unigene and a gene-specific virtual northern blot (VNB) algorithm. Unigene and VNB combined correctly predicted the expression of the genes required for fructose metabolism in liver, kidney, and small intestine. Both methods indicated brain, breast, lymphocytes, muscle, placenta, and stomach additionally express this set of genes. Expression of the genes for GLUT5 (glut5) and ketohexokinase (khk) in neurons was validated by immunohistochemistry and RNA in situ hybridization, respectively. Using stringent controls, clear expression of glut5 and khk was localized to Purkinje cells in the cerebellum. Cerebellum was used to oxidize fructose to carbon dioxide. Together, these data suggest that these neurons in the brain are able to utilize fructose as a carbon source.

Animals↗

PubMed2005

Delusions and decision-making style: use of the Need for Closure Scale.

Clinicians and researchers have suggested that rapidity in belief formation, due to having a high 'need for closure' (NFC), may contribute to the acceptance of delusional explanations. The aim of the study is to determine whether NFC has such a direct link with delusions. A secondary aim is to examine if NFC is related to the delusion-associated reasoning process of 'jumping to conclusions'. One hundred and eighty-seven patients with psychosis, recruited for a treatment trial of psychological therapy (the PRP trial), completed the Need for Closure Scale (NFCS), symptom measures, and probabilistic reasoning tasks. The NFCS was considered in terms of its two dimensions: a desire for simple structure and a preference for quick, decisive answers. The individuals with psychosis reported being poor at making quick, decisive answers but required a greater need for simple structure. NFC was associated with levels of anxiety and depression. There were weak links between NFC and both positive and negative symptoms of psychosis, but these were explained by differences in affect. NFCS scores were unrelated to jumping to conclusions. Contrary to the argument that NFC is directly linked to delusions, individuals with delusions actually perceive themselves as indecisive. There was no evidence that NFC-at least as assessed by the NFCS-could be a proximal cause of delusions. Any potential effect on psychotic symptom presentation is indirect, mediated through affect. The use of the NFCS on its own in the study of psychotic symptoms cannot be recommended.

Adult↗

PubMed2005

Reasoning, emotions, and delusional conviction in psychosis.

The aim of the study was to elucidate the factors contributing to the severity and persistence of delusional conviction. One hundred participants with current delusions, recruited for a treatment trial of psychological therapy (PRP trial), were assessed at baseline on measures of reasoning, emotions, and dimensions of delusional experience. Reasoning biases (belief inflexibility, jumping to conclusions, and extreme responding) were found to be present in one half of the sample. The hypothesis was confirmed that reasoning biases would be related to delusional conviction. There was evidence that belief inflexibility mediated the relationship between jumping to conclusions and delusional conviction. Emotional states were not associated with the reasoning processes investigated. Anxiety, but not depression, made an independent contribution to delusional conviction.

Adolescent↗

PubMed2005

The psychology of persecutory ideation II: a virtual reality experimental study.

A cognitive model of persecutory delusions is used to predict the occurrence of nonclinical paranoid thoughts in a virtual reality environment. Scorers across the range of paranoia entered a virtual reality scene populated by five computer characters programmed to behave neutrally (N = 30). Many appraisals of the computer characters were positive or neutral. However, there were also persecutory thoughts about the characters. Providing evidence of the validity of the experimental method, persecutory ideation was predicted by higher trait paranoia and a greater sense of presence in the environment. The psychological variables from the cognitive model that predicted persecutory ideation were anxiety, timidity, and hallucinatory predisposition. Further, hallucinatory predisposition distinguished the prediction of paranoid thoughts from social anxiety in virtual reality. It is concluded that nonclinical paranoid thoughts are most closely associated with emotional disturbances and anomalous experiences. Extreme reasoning bias may particularly contribute to the development of clinical phenomena.

Adult↗

PubMed2005

The psychology of persecutory ideation I: a questionnaire survey.

Paranoia is a complex phenomenon that is likely to arise from a number of factors. In a recent cognitive model of persecutory delusions, three key factors are highlighted: anomalous experiences, emotion, and reasoning. In the first of two linked studies, we report a questionnaire survey of nonclinical paranoia designed to assess the theoretical model. A nonclinical population (N = 327) completed measures of paranoia, anomalous experiences (hallucinatory predisposition, perceptual anomalies), emotion (depression, anxiety, self-focus, stress, interpersonal sensitivity), and reasoning (need for closure). Paranoia was best explained by separation anxiety, depression, fragile inner self, hallucinatory experiences, discomfort with ambiguity, stress, self-focus, perceptual anomalies, and anxiety. The findings are consistent with the central predictions within the model of paranoia.

Adult↗

PubMed2005

Grandiose delusions: an experimental investigation of the delusion as defense.

Two distinct roles for emotion in the development of delusions have been outlined. Some authors argue that delusions defend against low self-esteem and negative emotion (the delusion-as-defense account). Other authors hypothesize that delusions are not a defense but are a direct reflection of emotion and associated processes (the emotion-consistent account). An empirical investigation was conducted of the delusion-as-defense account with reference to grandiose delusions. Twenty individuals with grandiose delusions and 21 individuals without mental illness were compared on overt and covert measures of self-esteem. No evidence for a discrepancy between overt and covert self-esteem in individuals with grandiose delusions was found. One potential interpretation of the results is that the tasks were not able to penetrate defensive processes. However, we argue that in this group, the grandiose delusions do not currently defend against low self-esteem. Instead, grandiose delusions may in part be direct exaggerations of the emotional state of individuals.

Adult↗

PubMed2005

Trauma and hallucinatory experience in psychosis.

Recent research indicates that there may be phenomenological, symptom, and diagnostic associations between trauma and hallucinations. However, the nature of the relationship is poorly understood from a psychological perspective. We report a theoretically informed phenomenological study. From descriptions of reported traumas and hallucinations, we assessed the rates of four types of hypothesized association between traumas and hallucinations (direct, indirect, stress, and none) in 75 participants with nonaffective psychosis. In a subgroup who had experienced trauma (N = 40), 12.5% had hallucinations with similar themes and content to their traumas, 45% had hallucinations in which the themes were the same but not the content, and 42.5% had no identifiable associations between their hallucinations and previously experienced trauma. Traumas rated as intrusive were significantly associated with hallucinations rated as intrusive, although intrusive hallucinations were not associated with traumas in general. The traumas most likely to be associated with hallucinations were sexual abuse and bullying.

Accidents↗