Attentional and memory bias in persecutory delusions and depression

BACKGROUND: Previous research has indicated that persecutory delusions and depression may share similar cognitive biases at implicit levels of processing, but differentiate at explicit levels, supporting the theory that paranoia may have a protective function against underlying negative schemata. The study aimed to investigate attentional bias and both implicit and explicit memory biases for personally salient and standardised emotional stimuli in persecutory delusions and depression. SAMPLING: 36 participants, with 12 in each group, were interviewed in order to generate personally salient stimuli to be employed within the cognitive tests. Standardised emotional stimuli were additionally employed as a control. Participants completed two probe detection tasks, one including personally salient stimuli and one including standard emotional stimuli. Memory for the stimuli presented in this task was assessed by a free recall task (explicit memory) followed by a word completion task (implicit memory). RESULTS: On an implicit memory task, both the deluded and depressed groups displayed comparable retrieval of positive and negative words. However, on the explicit memory task, the depressed group demonstrated a bias for negative stimuli, whereas the deluded group demonstrated a bias for positive stimuli. The groups did not demonstrate an attentional bias for personally salient information. However, an attentional bias for standardised emotional stimuli was found in the depressed group, although this was not specific to either negative or positive stimuli. CONCLUSION: The results indicate that depression and persecutory delusions may share similar patterns of processing at an implicit level but differentiate at the explicit level, which may be indicative of cognitive avoidance of threatening stimuli in psychosis. However, this does not seem to be a feature of automatic attentional processes in people with persecutory delusions. Implications for further research are discussed.     

Deficit in negative emotional information processing in schizophrenia: Does it occur in all patients?

The nature of the impairment in the processing of emotional information in schizophrenia is still being debated. Some authors reported that schizophrenia patients would show deficits in the treatment processing of negative emotional information without a negative bias, as observed in controls, when in a combined emotional situation including positive/negative information. Eighteen subjects with paranoid schizophrenia in remission with a low level of negative symptoms and 18 control subjects were exposed to 108 pairs of pictures (International Affective Picture System) depicting different emotions (N = negative, P = positive, n = neutral) from six different combinations: N/N, P/P, n/n, P/N, P/n, and N/n. The subjects responded by clicking on a right or left button in response to a negative or positive feeling toward the stimuli (forced choice task). They were also asked to classify each of the individual pictures as positive, negative, or neutral (emotion-recognition task). In this well-defined group of paranoid schizophrenia patients in remission, we observed the persistence of a negative bias when an ambiguous situation is displayed (P/N) with the absence of an impairment in negative emotional information recognition and the presence of a positive bias in the recognition of neutral stimuli, reflecting a tendency to keep arousal-provoking perceptual cues from entering into subjective awareness.     

Relation between emotional face memory and social anhedonia in schizophrenia

Background

There is an interest in investigating the relation between emotional memory impairments in schizophrenia and specific symptom dimensions. We explored potential links between emotional memory and social anhedonia severity in patients with schizophrenia and in healthy individuals.

Methods

Twenty-nine patients with schizophrenia and 27 matched healthy individuals completed the Chapman Revised Social Anhedonia Scale and then performed an emotional face recognition memory task involving happy, sad and neutral face expressions. We calculated emotional memory performance using 2 independent measures: the discrimination accuracy index Pr and the response bias Br. We also measured valence ratings of the face stimuli. We performed correlation analyses using the inter-individual variability in social anhedonia severity and the individual score obtained for each memory performance variable and for each face valence rating condition.

Results

Patients with schizophrenia reported higher levels of social anhedonia compared with healthy individuals. They also showed lower recognition accuracy for faces compared with healthy participants. We found no significant correlation between social anhedonia severity and any of the memory performance variables for both patients with schizophrenia and healthy individuals. Regarding potential links between social anhedonia severity and face valence ratings, we found that individuals with elevated social anhedonia had a tendency to rate the face stimuli as more negative.

Limitations

Our negative finding may be partly explained by a lack of statistical power owing to our small patient sample. In addition, our patient sample had unusually high estimated IQ scores, which highlights potential issues regarding the generalization of our findings. Finally, we used a yes–no recognition memory task with a very short retention interval delay.

Conclusion

Our results suggest that social anhedonia is not directly linked to emotional memory deficits and biases and does not interfere with the modulatory effect of positively valenced emotion on memory.     

Emotional discomfort and impairments in verbal memory in schizophrenia

Research has demonstrated that impairments in verbal memory in schizophrenia are linked with psychosocial deficits. Less is known, however, about their relationship to clinical features of illness. This study explores the hypothesis that impairments in verbal memory, particularly forms of memory requiring deeper levels of encoding, are uniquely linked to symptoms of dysphoria or emotional discomfort. Accordingly, we examined the association between concurrent measures of symptoms and verbal memory for 84 subjects with schizophrenia. Measures of positive, negative, cognitive, excitement and emotional discomfort symptoms were derived from factor scores of the Positive and Negative Syndrome Scale. Verbal memory was assessed using two tests requiring relatively superficial levels of encoding: The Hopkins Verbal Memory Test and the Digit Span subtest; and one test requiring deeper levels of encoding: the Logical Memory subtests I and II. As predicted, multiple regressions controlling for age, education and attention revealed that poorer performance on Logical Memory was strongly associated with greater levels of emotional discomfort (R(2)=0.22 and 0.25, respectively) while performance on the Hopkins test was related to cognitive symptoms scores (R(2)=0.08 and 0.09, respectively). Implications for the conceptualization of verbal memory deficits in schizophrenia are discussed.     

Left DLPFC rTMS stimulation reduced the anxiety bias effect or how to restore the positive memory processing in high-anxiety subjects

In the present research we explored the role of the dorsolateral prefrontal cortex (DLPFC) in memory retrieval process of positive vs. negative emotional stimulus, as a function of the anxiety levels. Anxiety behavior showed a consistent attentional bias toward negative and aversive memories, induced by a right frontal cortical superiority. This effect was analyzed by using a rTMS paradigm that induced a cortical activation of the left DLPFC. Subjects, who were divided in two different groups depending on their anxiety level (high/low-anxiety, State-Trait-Anxiety-Inventory, STAI), were required to perform a task consisting of two experimental phases: an encoding-phase, where some lists composed by positive and negative emotional words were presented to the subjects; and a retrieval-phase, where the old stimuli and new stimuli were presented for a recognition performance. We found that the rTMS stimulation affects the memory retrieval of emotional material. High-anxiety subjects benefit in greater measure from the left DLPFC stimulation with a reduced negative bias. This result suggested that left DLPFC activation favors the memory retrieval of positive emotional information and might limit the “unbalance effect” induced by a right hemispheric superiority at a high level of anxiety. The potentiality of TMS for anxiety behavior modulation was also discussed.     

Negativity bias in attitude learning: A possible indicator of vulnerability to emotional disorders?

Negativity biases, i.e., tendencies for negative features and interpretations to predominate over positive, are known to play a role in the etiology and maintenance of emotional disorders. Both depression and anxiety have been associated with such negative cognitive styles. Recently, Fazio, R.H., Eiser, J.R., and Shook, N.J. [(2004). Attitude formation through exploration: Valence asymmetries. Journal of Personality and Social Psychology, 87, 293-311] have observed similar valence asymmetries in the domain of attitude formation and generalization. The present research examined the possibility that the extent to which individuals display a learning bias in attitude formation is related to negative cognitive style and emotional disorder symptoms. Participants played a computer game that required learning whether novel stimuli produced positive or negative outcomes. Poorer learning was associated with more negative cognitive style, greater depression, and a tendency toward greater anxiety. Interestingly, these relations were most evident with respect to the learning of the positive stimuli, suggesting that an under-appreciation of positive objects and events may underlie vulnerability to emotional disorders. The potential value of various indices of negativity bias that can be assessed when examining attitude formation and generalization is discussed.     

精神分裂症症状与认知功能损害的关系

目的：探讨精神分裂症症状与认知功能损害的关系。方法：对１８例阴性精神分裂症和１５例阳性精神分裂症采用氯氮平治疗;对１１例阴性精神分裂症和１３例阳性精神分裂症采用利培酮治疗。并分别评估其治疗前和治疗８周后的阳性症状,阳性症状记忆,注意及执行功能。结果：精神分裂症的记忆损害与阴性症状和阳性症状都呈显著性相关,注意及执行功能损害与阴性症状显著相关,与阳性症状无明显相关;记忆随思维贫乏的改善而改善,注意和执行功能损害的改善与症状的改善无明显相关。结论：精神分裂症认知功能损害主要与阴性症状相关,但精神分裂症的大部分认知功能并不随阴性症状改善而改善。     

Verbal memory errors and symptoms in schizophrenia.

OBJECTIVE: To extend and test hypotheses linking positive and negative symptoms to selective aspects of verbal memory in schizophrenia. BACKGROUND: Verbal memory includes the ability to discriminate and prevent the intrusion of irrelevant information into recall and recognition. This ability has been proposed as a cognitive process that differentially mediates positive and negative symptoms. METHOD: Four error discrimination and 1 general recall memory index from the California Verbal Learning Test as well as general ability (IQ) and sex were used as predictors of symptom ratings in 55 schizophrenia patients within a regression framework. RESULTS: Intrusion errors during free recall contributed significantly to the prediction equation for negative symptoms (Brief Psychiatric Rating Scale). In contrast, positive symptoms and general psychopathology were not predicted by any of the discrimination indices. However, general recall memory (California Verbal Learning Test total words trials 1-5) contributed significantly to the prediction of general psychopathology and marginally to the prediction of negative symptoms. CONCLUSIONS: Impaired recall memory predicts levels of nonspecific psychopathology in schizophrenia. Negative symptoms associate with low intrusion error rates, but there is no evidence of an association between elevated errors and positive symptoms.     

Impairment of story memory organization in patients with schizophrenia

The aim of the present paper was to examine the organization of story memory in schizophrenia. Participants were 35 patients with schizophrenia and 24 healthy subjects who completed the Wechsler Memory Scale-Revised. The organization of story memory was evaluated with the Logical Memory subtest. Schizophrenia patients scored significantly lower than controls on thematic sequencing, and significant negative correlations were found between positive symptoms and thematic sequencing. These findings suggest that schizophrenia has deficits in organization of story memory, which are related to symptoms such as disorganized thoughts and behavior.     

Neural correlates of emotional working memory in patients with mild cognitive impairment

Emotional stimuli can have beneficial effects on memory in healthy aged subjects and partly on patients with dementia. So far, no experimental study has explored the effects of memory for emotional stimuli in patients with mild cognitive impairment (MCI), a concept that describes a transitional state between normal aging and dementia. The present fMRI study explored working memory for emotional stimuli in 16 patients with amnestic MCI (aMCI) and 16 healthy aged participants. Subjects performed an n-back task (2-back) with neutral, positive, and negative emotional pictures. The analysis focused on target processing. Results showed that groups did not differ in working memory performance. In healthy aged participants emotional targets had no significant impact on working memory. In patients with aMCI a negativity bias was observed, indicating that negative targets were better remembered compared to neutral and positive targets. Regarding fMRI results, both groups showed an increase in functional activity in prefrontal and lateral parietal brain regions associated with target processing. As a key result, we observed significant group by emotion interaction effects in the precuneus. Healthy aged participants showed a signal decrease in the left precuneus for positive compared to neutral targets. The precuneus deactivation in healthy aged participants may indicate a disengagement of self-referential processes towards task-related processes. Patients with aMCI revealed a signal increase in the right precuneus for negative compared to neutral targets. This increase in precuneus activity, combined with a behavioural facilitation effect, may indicate a mechanism to compensate disease related processes in aMCI.     

Emotional memory function, personality structure and psychopathology: a neural system approach to the identification of vulnerability markers

It is well established that emotional events are ingrained stronger into memory relative to neutral events. Facilitated emotional memory is highly variable between individuals within the normal population and is particularly exacerbated in those diagnosed with mood and anxiety disorders. In order to elucidate how variation of enhanced emotional memory within the normal population may manifest into psychopathological states, we explored the convergence between studies investigating the neural systems engaged in emotional memory facilitation and studies investigating how these systems differ from person to person. Converging evidence highlights the roles of three neural systems (1. Amygdala function and attention, 2. Neuroendocrine function, 3. Interactive effects with mood) that all govern emotional memory facilitation and are highly variable between individuals as a function of personality. We applied this neural system approach to models of vulnerability of three forms of psychopathology that are particularly characterized by atypical emotional memory function (depression, generalized anxiety disorder and post-traumatic stress disorder). This application suggests that the incorporation of known vulnerability markers across psychological, neuroimaging and neuroendocrinological domains is cardinal to how susceptibility is conceptualized and assessed in these disorders.     

The effect of acute tryptophan depletion on emotional distraction and subsequent memory

Serotonin is a key neurotransmitter involved in emotional regulation and memory. A number of studies using acute tryptophan depletion (ATD) in healthy subjects have shown that a temporary serotonin reduction both induces a negative emotional bias and impairs long-term memory. However, little is known about the specific effects of ATD on emotional memory. Using functional magnetic resonance imaging (fMRI), we investigated the effect of ATD on negative memory and executive function in healthy volunteers. Our emotional oddball task required participants to distinguish infrequently presented targets from distracting negative and neutral pictures. Memory for the distracting pictures was tested 1 h following the fMRI session. ATD selectively enhanced memory for negative distractors relative to neutral distractors and increased activation in response to the negative distractors in the left orbital-inferior frontal, dorsomedial prefrontal and bilateral angular gyri. ATD also induced greater activation in the left inferior frontal gyrus and anterior cingulate across all stimuli. Stronger frontal activation to distractors was positively correlated with memory performance on ATD but not control days, indicating a possible compensatory mechanism for coping with increased task demand under the ATD challenge. These findings highlight the importance of serotonin in negative memory with implications for mood disorders.     

In support of Bleuler: objective evidence for increased affective ambivalence in schizophrenia based upon evocative testing

BackgroundAmbivalence and anhedonia have long been identified as schizophrenic symptoms. However, ambivalence has rarely been studied, and in most evocative studies, schizophrenia participants are not anhedonic. Affective neurosciences posit two evaluative systems (one for Positivity and one for Negativity), the coactivation of which produces ambivalence, and point to two asymmetries in affective processing: Positivity Offset (which measures our capacity to explore the environment) and Negativity Bias (a measure of reactivity to intense threat). These characteristics have not received much attention in schizophrenia research.MethodsSixty-four individuals with schizophrenia and 32 non-patient control participants completed an evocative emotional task with pictures, sounds and words of various valences and intensities. Following each presentation, participants rated the level of pleasantness, unpleasantness, and arousal elicited by the stimulus. Finally, participants completed questionnaires on anhedonia, and practical life skills were assessed.ResultsSchizophrenia participants showed higher levels of ambivalence, greater arousal, greater Positivity Offset, and non-significantly different hedonic capacities and Negativity Bias. Ambivalence to positive stimuli significantly correlated with duration of illness, current level of psychopathology, anhedonia questionnaires and practical life skills. Schizophrenia patients with negative symptoms did not differ from patients without negative symptoms on computer tasks.ConclusionsAmbivalence is greater in schizophrenia, and can be understood as a de-differentiation of the activation of the two evaluative systems. Ambivalence to positive stimuli, which may reflect early-stage affective processing is associated with impairments in higher-level emotional processes and in everyday functioning. Future studies should clarify the status of anhedonia in schizophrenia.     

Effects of testosterone on attention and memory for emotional stimuli in male rhesus monkeys

Increasing evidence in humans and other animals suggests that testosterone (T) plays an important role in modulating emotion. We previously reported that T treatment in rhesus monkeys undergoing chemically induced hypogonadism results in increased watching time of videos depicting fights between unfamiliar conspecifics (Lacreuse et al., 2010). In the current study, we aimed to further investigate the effect of T manipulations on attention and memory for emotional stimuli in male rhesus monkeys. Six males (7 years old) were administered Depot Lupron to suppress endogenous T levels and treated with either testosterone enanthate (TE, 5 mg/kg) or oil, before crossing over to the alternate treatment. Animals were tested for 16 weeks on two computerized touchscreen tasks with both social and nonsocial emotional and neutral stimuli. The Dot-Probe task was used to measure attention, and the Delayed-Non-Matching-to-Sample task with a 1s delay (DNMS) was used to measure recognition memory for these stimuli. Performance on the two tasks was examined during each of four month-long phases: Baseline, Lupron alone, Lupron+TE and Lupron+oil. It was predicted that T administration would lead to increased attention to negative social stimuli (i.e., negative facial expressions of unfamiliar conspecifics) and would improve memory for such stimuli. We found no evidence to support these predictions. In the Dot-Probe task, an attentional bias towards negative social stimuli was observed at baseline, but T treatment did not enhance this bias. Instead, monkeys had faster response times when treated with T compared to oil, independently of the emotional valence or social relevance of stimuli, perhaps reflecting an enhancing effect of T on reward sensitivity or general arousal. In the DNMS, animals had better memory for nonsocial compared to social stimuli and showed the poorest performance in the recognition of positive facial expressions. However, T did not affect performance on the task. Thus, even though monkeys were sensitive to the social relevance and emotional valence of the stimuli in the two tasks, T manipulations had no effect on attention or memory for these stimuli. Because habituation to the stimuli may have mitigated the effect of treatment in the attentional task, we suggest that T may increase attentional biases to negative social stimuli only during early exposure to the stimuli with acute treatment or when stimuli are highly arousing (i.e., dynamically presented) with chronic treatment. In addition, the data suggest that T does not enhance working memory for emotional stimuli in young male macaques.     

Emotional priming of facial affect identification in schizophrenia

Twenty-three schizophrenia subjects were compared with healthy and clinical control subjects on an emotional priming task. Positive and negative emotional facial expressions were presented as primes, followed by a neutral pattern mask, then an emotionally neutral face as target. The prime-mask-target sequence was arranged to allow conscious perception of only the targets. Subjects had to judge if they had seen a pleasant or an unpleasant facial expression. All subjects judged the neutral target as significantly more unpleasant when negative emotional facial expressions were presented as primes as compared with positive or neutral facial expressions as primes. This judgment shift was significantly stronger in schizophrenia subjects than in control subjects. The stronger priming of schizophrenia subjects may reflect a stronger influence of automatically processed emotional stimuli on judgments. We suggest that increased spreading activation of emotional information might be related to low social/emotional functioning of the individual with schizophrenia.     

Evidence of schizophrenia patients' reduced perceptual biases in response to emotion chimera

The goal of the study was to determine whether dextral individuals with schizophrenia display atypical perceptual biases in response to faces in general, or whether they display atypical perceptual biases in response to emotional facial cues. To this end, we assessed perceptual processing in schizophrenia patients with four types of free-vision chimeric stimuli. Perceptual biases were evaluated in 45 schizophrenia patients and in 46 controls using two face (emotion, gender) tasks and two nonface (dots, gradients) tasks. In response to the emotion chimera, the patients with schizophrenia displayed a reduced left perceptual bias. The two groups did not differ significantly in their response to the gender chimera or to the two nonface chimera. These findings are consistent with the assertion that schizophrenia patients have impaired emotional perception. In the discussion we consider possible reasons for schizophrenia patients' difficulty comprehending emotional facial stimuli. We suggest that schizophrenia patients' reduced perceptual bias in response to the emotion chimera reflects a hypothesized affective information-processing deficit.     

Predictors of early stable symptomatic remission after an exacerbation of schizophrenia: The significance of symptoms,neuropsychological performance and cognitive biases

Neuropsychological deficits and severity of initial psychopathology have been repeatedly associated with poor symptomatic outcomes in schizophrenia. The role of higher-order cognitive biases on symptomatic outcomes of the disorder has not yet been investigated. The present study aimed to assess the contribution of cognitive biases, psychopathology and neuropsychological deficits on the probability of achieving early symptomatic remission after a psychotic episode in patients with schizophrenia. Participants were 79 patients with a DSM-IV diagnosis of schizophrenia or schizoaffective disorder undergoing an acute psychotic episode, and 25 healthy controls. According to psychopathology assessments, patients were split into those who had achieved remission after an average follow-up interval of 7 months, and those who had not (NR). Patients who achieved remission exhibited higher premorbid IQ and better performance on the TMT-B, as well as lower baseline positive, disorganized and distress symptoms than NR patients. TMT-B performance and positive symptoms at baseline were the best predictors of remission. Cognitive biases and negative symptoms were not associated with later remission. The findings highlight the significance of initial symptom severity for at least short-term symptomatic outcomes and, thus, the importance of adequate symptomatic treatment and prevention of psychotic outbreaks in patients.     

The Effects of Clozapine on Negative Symptoms in Patients with Schizophrenia with Minimal Positive Symptoms

The effectiveness of clozapine in the treatment of the negative symptoms of schizophrenia remains controversial, as improvements in negative symptoms are invariably accompanied by improvements in positive symptoms and neurological side effects. We examined the effectiveness of treatment with clozapine on negative symptoms in a cohort of patients with minimal positive symptoms. Improvements in positive and negative symptoms were measured by BPRS ratings in a subgroup of schizophrenic patients (n=17, from a state hospital cohort of 75) with minimal positive symptoms, who had received clozapine for 6 months. In this subgroup, significant improvements were noted by a composite score on the three negative symptom items of emotional withdrawal, blunted affect, and motor retardation. Positive and depressive symptoms remained unchanged. The remaining cohort (n=58) showed improvements in overall psychopathology including positive, negative, and depressive symptoms. Interestingly, nearly 50% of each group were discharged from the hospital. These findings suggest that clozapine may be beneficial in the treatment of core negative symptoms, even in the absence of other improvements in psychopathology. This effect of clozapine may be a function of its unique pharmacological profile.     

The effect of mood and arousal on UCS expectancy biases.

This paper reports two studies investigating the role of mood and arousal on the development of UCS expectancy biases to fear-relevant and fear-irrelevant stimuli. Experiment 1 found that, compared with a neutral control condition, individuals in both experimentally-induced positive and negative moods significantly overestimated the possibility of aversive outcomes following all types of stimuli in a hypothetical thought' conditioning experiment. Experiment 2 found that this UCS expectancy bias produced by both positive and negative mood could not be explained by the effect that these mood states might have on arousal independently of the valency of the mood. The findings appear to be explained best by emotional response categorisation theory (Psychol. Rev. 106 (1999) 337-361), which predicts that individuals would be more likely to view emotionally valenced stimuli as similar when in an emotional state. It is argued that, while negative mood may be a genuine vulnerability factor for the development of anxiety-relevant threat-outcome expectancies, the effects found with positive mood in the current studies may have less ecological relevance to real-world aetiologies.     

Emotional memory in schizophrenia

Emotionally arousing scenes are better remembered than neutral ones. The biological basis of this emotional memory effect has been studied in lesion and neuro-imaging studies and depends upon an interaction between the amygdala and medial temporal lobe memory systems including the hippocampus. This study sought to investigate whether patients with schizophrenia had performance deficits on emotional memory tasks consistent with abnormal amygdala function. Patients with schizophrenia and matched control subjects were shown scenes with negative, positive and neutral emotional content. Subjects rated the slides according to how emotionally arousing they found them and then performed surprise memory tests at 10 min (recall) and 3 weeks (recall and recognition). Subjects with schizophrenia did not differ from control subjects in their ratings of the slides. However, patients showed a significant loss of the emotional enhancement of recognition memory for both negative and positive scenes. In addition, patients showed an overall deficit in recall memory, with a selective impairment in recall of the most arousing negative slides. These findings are consistent with the view that medial temporal lobe and in particular amygdala function is abnormal in schizophrenia.