Neuropsychological functioning in early onset psychotic disorders

This paper examines whether neuropsychological profiles of youth with early onset psychotic disorders predicted diagnostic or clinical status. Youth with schizophrenia (n=27), bipolar disorder (n=22), and psychosis NOS (n=20) were included. Subjects received an extensive neuropsychological evaluation, including measures of general cognition, attention, memory, and executive functioning. Medication status was not controlled. No statistically significant neurocognitive differences across diagnostic groups were found. Compared to standardized norms, youth with schizophrenia demonstrated deficits in general cognition, verbal learning, recall, sustained effort, and social knowledge. Subjects with bipolar disorder and psychosis NOS exhibited deficits on measures of verbal learning, recall, and sustained effort similar to those of youth with schizophrenia. Neurocognitive deficits in memory and attention appeared to be common among youth with psychotic illnesses, regardless of diagnosis. Those with schizophrenia may have greater global cognitive deficits and problems with social knowledge. Across diagnoses, subjects demonstrated relative strengths on tests that provided them with immediate feedback, and performed most poorly on tests requiring delayed recall.     

Memory performance of geriatric and nongeriatric chronic schizophrenic patients: a cross-sectional study.

Memory functioning has been studied extensively in nongeriatric schizophrenic patients, leading to the suggestion that schizophrenic patients manifest a "subcortical" pattern of memory deficits. Few previous studies examined very poor outcome patients with a chronic course of hospitalization. This study examined the association of age and global cognitive dysfunction with verbal and spatial learning and delayed recall, as well as examining differential impairments in delayed recall as compared to delayed recognition memory. Sixty-six chronic schizophrenic patients were studied, with 30 of these patients over the age of 65. Verbal (California Verbal Learning Test) and spatial (Biber Figure Learning Test) serial learning and delayed memory tests were administered. All aspects of memory functioning were correlated with estimates of global cognitive status. When global cognitive status was controlled, age effects were still found for the majority of the memory measures. Delayed recognition memory was not spared, being performed as poorly as delayed recall. In contrast to previous studies of better-outcome patients with schizophrenia, geriatric patients with chronic schizophrenia performed more poorly than nongeriatric patients. The lack of sparing of delayed recognition memory suggests that previous findings of specific recall memory deficit and a subcortical profile of memory impairments may apply to schizophrenic patients with less severe global cognitive impairments. These data suggest that poor-outcome patients may have a pattern of memory impairments that has some features in common with cortical dementia.     

Verbal memory processes in schizophrenia patients and biological relatives of schizophrenia patients: intact implicit memory, impaired explicit recollection

Verbal memory deficits are arguably the most common cognitive abnormalities in biological relatives of schizophrenia patients. Because verbal memory is a complex cognitive function, it is necessary to differentiate its intact and compromised aspects in order to reveal aberrant neural systems that reflect genetic risk in relatives of schizophrenia patients. Using an experimental verbal memory task, we examined encoding, free-recall, repetition priming, and recognition of verbal material in 22 schizophrenia patients, 22 first-degree biological relatives of schizophrenia patients, and 23 nonpsychiatric control participants. Schizophrenia patients exhibited intact repetition priming, but worse size judgment task performance (encoding), recall, and recognition than the control participants. Biological relatives of schizophrenia patients exhibited intact size judgment task performance, repetition priming, and recognition, but a free-recall deficit. Although size judgment task performance at encoding was associated with recall of verbal material in schizophrenia and control groups, in the relative group encoding performance was associated with the degree of repetition priming. Findings are consistent with impaired explicit recollection of verbal material, but intact implicit verbal memory in schizophrenia patients and biological relatives of schizophrenia patients.     

Compromised memory function in schizophrenia and temporal lobe epilepsy

The purpose of this study was to investigate compromised memory function of schizophrenia patients in comparison with temporal lobe epilepsy patients, whose memory impairments result from a clear lesion. The authors hypothesized that schizophrenia patients would show poorer immediate and delayed recall performances in verbal and visual memory tasks. The study sample consisted of a healthy comparison group of 30 subjects and three patient groups comprising 76 schizophrenia patients, 93 left temporal lobe epilepsy patients, and 72 right temporal lobe epilepsy patients. The authors assessed immediate recall, delayed recall, and delayed retention. Tasks were subdivided into two categories (easy and difficult), and then patient memory dysfunction was compared among the memory tests. The authors observed material-specific memory impairment, where the left temporal lobe epilepsy group showed severe verbal memory impairment and the right temporal lobe epilepsy group showed severe visual memory impairment. A moderate impairment was found in immediate and delayed verbal memory in schizophrenia patients, and the impairment of visual memory was amplified with delayed recall. Such a result can be interpreted not only as a generalized cognitive deficit, but also as an integrative dysfunction involving the mesial temporal and frontal lobes in the left and right hemispheres, whereby the lesion site cannot be determined selectively. Our results show that the selection of a memory task that cannot be influenced by verbal mediation is very important for analyzing memory dysfunction in schizophrenia patients.     

抑郁症和早期阿尔茨海默病的记忆和执行功能

目的 研究抑郁症和早期阿尔茨海默病(AD)的神经心理学特征,试图运用神经心理学评估对两者进行鉴别。方法 对32例单相抑郁症、38例早期AD和34例对照进行WHO-UCLA词语学习、词语流畅、复杂图形和逻辑记忆的评估。结果 早期AD组神经心理学测验得分最低,抑郁症组次之,对照组最高,3组之间有显著性差异(P<0.01);抑郁症组仅表现为词语学习和逻辑记忆的自由回忆以及语义流畅的损害(P<0.05),而早期AD组表现为全面的认知功能损害(P<0.01);逐步判别分析提示,复杂图形延迟自由回忆、词语学习长时延迟自由回忆和语义流畅是区分抑郁症组和早期AD组的重要指标。结论 抑郁症和早期AD认知功能损害的特征不同,长时延迟自由回忆、再认和语义流畅能够区分早期AD和抑郁症。     

Verbal memory and verbal fluency in adolescents with schizophrenia spectrum disorders

Aim: Although impaired verbal memory and verbal fluency are frequently found in adults with schizophrenia, there has been a paucity of studies investigating adolescents with schizophrenia. Thus, the aim of the present study was to investigate the main subcomponents of verbal memory and verbal fluency in adolescents with schizophrenia spectrum disorders. Methods: Verbal learning and memory and verbal fluency was assessed in 21 adolescents with schizophrenia spectrum disorders (mean age, 15.4 years) compared with 28 healthy adolescents (mean age, 15.1 years). Results: The patient group performed significantly below healthy controls on measures of learning, delayed recall and on a frequency estimation task. No differences between the groups were found for measures of recognition, retention, implicit memory, or susceptibility to interference. Although they had impaired delayed recall the patients remembered most of what they actually learned. The patient group was impaired on phonological and semantic fluency, but there were no differences between the groups with respect to clustering or switching on the fluency tasks, when controlling for total output. There was no disproportionate impairment in semantic, as compared to phonological fluency, in the patient group. Conclusions: Adolescents with schizophrenia spectrum disorders exhibit impairments in verbal learning and verbal fluency, which might have an impact on the individual's everyday functioning.     

Prose memory deficits associated with schizophrenia

Memory of contextual information is essential to one's quality of living. This study investigated if the different components of prose memory, across three recall conditions: first learning trial immediate recall, fifth learning trial immediate recall, and 30-min delayed recall, are differentially impaired in people with schizophrenia, relative to healthy controls. A total of 39 patients with schizophrenia and 39 matched healthy controls were recruited. Their prose memory, in terms of recall accuracy, temporal sequence, recognition accuracy and false positives, commission of distortions, and rates of learning, forgetting, and retention were tested and compared. After controlling for the level of intelligence and depression, the patients with schizophrenia were found to commit more distortions. Furthermore, they performed poorer on recall accuracy and temporal sequence accuracy only during the first initial immediate recall. On the other hand, the rates of forgetting/retention and recognition accuracy were comparable between the two groups. These findings suggest that people with schizophrenia could be benefited by repeated exposure to the materials to be remembered. These results may have important implications for rehabilitation of verbal declarative memory deficits in schizophrenia.     

Hopelessness,neurocognitive function,and insight in schizophrenia: relationship to suicidal behavior

Insight and hopelessness have been reported to be associated with suicidality in schizophrenia. In addition, there is evidence that diminished insight is correlated with impairment in some domains of cognitive function in schizophrenia. The purpose of this study was to clarify the relative importance for suicidality in patients with schizophrenia of hopelessness, cognitive dysfunction, and insight. This study included 333 patients with chronic schizophrenia who were prospectively studied. Insight was rated by the insight items from the Schedule for Affective Disorders and Schizophrenia (SADS) and the Hamilton Depression Rating Scale (HDRS). Positive, negative, and anxiety-depression symptoms were measured with the Brief Psychiatric Rating Scale (BPRS). Cognition was assessed with a neurocognitive battery, which included measures of attention and psychomotor speed, verbal fluency, verbal memory, working memory, and executive function. Current and lifetime suicidality was prospectively assessed. Hopelessness, substance abuse, and greater insight were associated with attempted suicide and suicidal ideation. Those with a history of lifetime, but not current, suicidality had better function on tests of psychomotor speed and attention, verbal working memory, verbal fluency, verbal memory, and executive function. Neurocognitive measures were not significantly correlated with hopelessness and insight. Hopelessness was more severe in those with current and lifetime suicidality. A multiple regression analysis was used to predict current and lifetime suicidality from hopelessness, substance abuse, insight, and cognitive factor scores. The regression models predicting current and lifetime suicidality indicated that hopelessness was the most important predictor of both (beta=0.41, p=0.0001; and beta=0.35, p=0.01, respectively). These findings suggest that hopelessness, substance abuse, greater insight into illness, and higher cognitive function are associated with greater suicidality in chronic schizophrenia, but that among these, hopelessness may be the principal predictor of suicidality.     

Neuropsychological correlates of insight in obsessive-compulsive disorder

Kashyap H, Kumar JK, Kandavel T, Reddy YCJ. Neuropsychological correlates of insight in obsessive–compulsive disorder. Objective: There are limited data on neuropsychological correlates of poor insight in obsessive–compulsive disorder (OCD). We hypothesize that poor insight may be associated with greater impairment in tasks of conflict resolution/response inhibition and possibly impairment in a task of verbal learning and memory. Method: Insight and neuropsychological functions were assessed in 150 subjects with DSM‐IV OCD. The neuropsychological data of 177 healthy control subjects were used for comparison. Results: Insight score correlated significantly with the Stroop Interference Test for conflict resolution/response inhibition (P = 0.002), and showed trends for significance with the Controlled Oral Word Association (COWA) average for verbal fluency (P = 0.021) and delayed recall on the Auditory Verbal Learning Test (AVLT) for verbal memory (P = 0.015). On regression analysis, the AVLT delayed recall, the COWA average, the Matrix score, the Yale‐Brown Obsessive–Compulsive Scale total score, and current antipsychotic use emerged as significant predictors of poorer insight. Conclusion: Poor insight is associated with greater impairments in conflict resolution/response inhibition, verbal memory, and fluency. Individuals with poorer insight may have difficulty in appropriately processing conflicting information, updating their memory with corrective information, and then accessing this corrective information to modify their irrational beliefs.     

Neurocognitive and social cognitive correlates of formal thought disorder in schizophrenia patients

The neurocognitive and social cognitive correlates of two types of formal thought disorder (i.e., bizarre-idiosyncratic and concrete thinking) were examined in 47 stable outpatients with schizophrenia. Both types of thinking disturbance were related to impairments in verbal learning, intrusions in verbal memory, immediate auditory memory, sustained attention, and social schema knowledge. Distractibility during an immediate memory task was associated with more frequent bizarre verbalizations but not concreteness. Impaired verbal learning rate and intrusions in verbal memory independently contributed to the prediction of bizarre responses, whereas intrusions in verbal memory and impaired immediate memory independently contributed to concrete thinking. This pattern of findings is consistent with the view that neurocognitive and, possibly, social cognitive deficits underlie these two aspects of formal thinking disturbance in schizophrenia.     

Processing speed mediates gender differences in memory in schizophrenia

The primary aim of this study was to examine whether processing speed mediates the association between gender and episodic memory in schizophrenia. Participants were 51 female and 51 male outpatients comparable on demographic, clinical, and cognitive variables. Memory tests included both verbal and visual measures. Both groups scored below the normative mean of the memory and processing speed tests, except that females performed slightly above the mean on face recognition. Females outperformed males on verbal memory, visual recognition, and processing speed. Mediation regression analyses showed processing speed mediated immediate and delayed recall for both verbal and visual memory measures. Thus processing speed appears to be a critical variable for understanding cognitive deficits in schizophrenia and may be an important target for cognitive rehabilitation.     

Processing Speed Mediates Gender Differences in Memory in Schizophrenia

The primary aim of this study was to examine whether processing speed mediates the association between gender and episodic memory in schizophrenia. Participants were 51 female and 51 male outpatients comparable on demographic, clinical, and cognitive variables. Memory tests included both verbal and visual measures. Both groups scored below the normative mean of the memory and processing speed tests, except that females performed slightly above the mean on face recognition. Females outperformed males on verbal memory, visual recognition, and processing speed. Mediation regression analyses showed processing speed mediated immediate and delayed recall for both verbal and visual memory measures. Thus processing speed appears to be a critical variable for understanding cognitive deficits in schizophrenia and may be an important target for cognitive rehabilitation.     

Learning and memory impairment in cocaine-dependent and comorbid schizophrenic patients

Impairments in verbal learning and memory functioning have been found to be cardinal features among individuals with schizophrenia as well as among non-schizophrenic cocaine abusers. Cognitive deficits in these areas, moreover, have been associated with poor treatment response and short-term outcome. Little is known, however, about the acute effects of cocaine abuse on schizophrenic patients' learning and memory functioning. Consequently, a potentially reversible and treatable source of cognitive impairment has been virtually ignored. The present study examined the extent of verbal learning and memory impairment in a group of cocaine-dependent schizophrenic patients (n=42) and a group of non-schizophrenic cocaine-dependent patients (n=21) within 72 h of the last cocaine use using the California Verbal Learning Test (CVLT). Schizophrenic patients (n=34) without any substance-use disorders were also tested in an identical time frame and served as a comparison group. Results revealed that all groups demonstrated significant learning and memory impairment relative to CVLT published age and gender corrected norms. Both cocaine-dependent and non-substance abusing schizophrenic groups presented a very similar pattern of impaired learning and recall performance across all CVLT task domains. Comorbid patients, in contrast, presented with marked deficits in their ability to learn and recall verbal information relative to either schizophrenic or cocaine-only groups. Moreover, the cocaine-abusing schizophrenic patients showed significant forgetfulness of the information that they did acquire during delayed recall conditions. The performance deficits exhibited by cocaine-abusing schizophrenic patients differed not only in relative severity of impairment, but also qualitatively in their increased rates of forgetfulness of acquired information. These results are interpreted in terms of the neurobiological substrates of learning and memory and the neurobiological impact of cocaine on schizophrenic patients' cognition during the early phase of inpatient hospitalization. These results suggest that comorbid patients should be targeted for specialized remediation efforts at the beginning phases of inpatient treatment.     

Physostigmine and cognition in schizotypal personality disorder

There is evidence that reduced cholinergic activity may play a role in the pathophysiology of cognitive impairment in the schizophrenia spectrum. We tested the effects of physostigmine, an anticholinesterase inhibitor, on visuospatial working memory as evaluated by the Dot test, and on verbal learning and recall as measured by a serial learning task in patients with schizotypal personality disorder. Physostigmine tended to improve the Dot test, but not serial verbal learning performance in these patients.     

Does cognition predict community function only in schizophrenia?: a study of schizophrenia patients, bipolar affective disorder patients, and community control subjects

Cognitive deficits predict functioning in schizophrenia; however, little is known as to whether the association is present in other mental disorders. If specific cognitive deficits uniquely predict functional impairment in schizophrenia the association of select aspects of brain dysfunction with daily living would suggest an intervention target and perhaps a means by which to improve the functioning of schizophrenia patients. The relationship of cognition and functioning was investigated in schizophrenia (n=39), bipolar affective disorder (n=27), and nonpsychiatric control (n=38) participants to determine whether the associations varied across groups. We examined verbal memory, verbal learning, verbal fluency, vigilance, executive functioning, symptomatology, and generalized cognitive functioning for associations with social function. Correlational analyses revealed particular cognitive domains (e.g., verbal memory) to be associated with social functioning in schizophrenia, bipolar, and control subjects; however generalized cognitive function and symptomatology were also associated with social functioning in patients. Multiple regression analyses revealed that in schizophrenia poor verbal memory predicted worse social functioning even after the effects of generalized cognitive dysfunction were considered. Verbal memory indices failed to account for variance in social function in bipolar patients and control subjects after consideration of generalized cognitive function. Bipolar patients with worse planning and problem solving tended to have worse social functioning. Therefore, unlike schizophrenia patients who may fail to process verbally mediated material, bipolar patients' difficulty with logical approaches to problems in daily living may have the greatest impact on their community function.     

PTSD symptoms and cognitive performance in recent trauma survivors

Chronic post-traumatic stress disorder (PTSD) has been associated with cognitive impairments involving memory and attention. The association between cognitive impairment and early PTSD symptoms is unknown, yet such association may lead to poorer processing of traumatic memories and thereby contribute to subsequent PTSD. This study evaluated the relationship between PTSD symptoms and cognitive functioning within 10 days of traumatic events. Forty-eight survivors were assessed for symptoms of PTSD, anxiety, depression and dissociation and for immediate and delayed verbal and figural memory, attention, learning and IQ. Survivors with high levels of PTSD symptoms showed impaired attention and immediate recall for figural information and lower IQ. They did not show, however, an impairment of verbal recall and learning. The observed difference was not explained by anxiety or dissociation. It disappeared, however, when the effect of depressive symptoms was controlled for. Lower IQ and impaired attention are associated with early PTSD and depressive symptoms. Poorer attention may have a role in shaping traumatic memories.     

Clinical and neuropsychological correlates of insight in schizophrenia and bipolar I disorder: does diagnosis matter?

BACKGROUND: Lack of insight is a well-recognized feature of schizophrenia and is associated with symptom severity and cognitive impairments. However, the diagnostic specificity of insight variables and their correlates is not known. To assess this specificity, we compared awareness of illness and neuropsychological function between patients with chronic schizophrenia and bipolar I disorder. METHOD: We assessed insight, level of psychopathology, and cognitive performance on a neuropsychological test battery in 37 patients with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition bipolar I disorder, 32 patients with schizophrenia, and 31 healthy subjects for comparison. RESULTS: There was no significant difference between the 2 diagnostic groups on general illness awareness. However, patients with bipolar disorder had better awareness of their symptoms and their pathologic nature compared to patients with schizophrenia. Similar patterns of association emerged between insight and clinical variables. General unawareness was associated with clinical severity, especially of the affective type, and working memory deficits (Wechsler Adult Intelligence Scale digit span) in both diagnostic groups. The contribution of other cognitive deficits to insight differed across the groups. Misattribution differed from the other aspects of insight in its relative independence of clinical and neurocognitive correlates. Both patient groups were neurocognitively impaired, with the schizophrenia group performing significantly worse on conceptual ability, verbal learning, visuospatial processing, and motor speed. CONCLUSIONS: The results suggest that differences in general insight in major mental disorders may be explained by symptom severity and working memory function rather than the specific diagnosis. Subcomponents of insight are influenced by different factors emphasizing the need to consider insight as multidimensional.     

Toward a Model of Cognitive Insight in First-Episode Psychosis: Verbal Memory and Hippocampal Structure

Our previous work has linked verbal learning and memory with cognitive insight, but not clinical insight, in individuals with a first-episode psychosis (FEP). The current study reassessed the neurocognitive basis of cognitive and clinical insight and explored their neural basis in 61 FEP patients. Cognitive insight was measured with the Beck Cognitive Insight Scale (BCIS) and clinical insight with the Scale to assess Unawareness of Mental Disorder (SUMD). Global measures for 7 domains of cognition were examined. Hippocampi were manually segmented in to 3 parts: the body, head, and tail. Verbal learning and memory significantly correlated with the BCIS composite index. Composite index scores were significantly associated with total left hippocampal (HC) volume; partial correlations, however, revealed that this relationship was attributable largely to verbal memory performance. The BCIS self-certainty subscale significantly and inversely correlated with bilateral HC volumes, and these associations were independent of verbal learning and memory performance. The BCIS self-reflectiveness subscale significantly correlated with verbal learning and memory but not with HC volume. No significant correlations emerged between the SUMD and verbal memory or HC volume. These results strengthen our previous assertion that in individuals with an FEP cognitive insight may rely on memory whereby current experiences are appraised based on previous ones. The HC may be a viable location among others for the brain system that underlies aspects of cognitive insight in individuals with an FEP.     

Relationship between psychopathology and cognitive functioning in schizophrenia

The purpose of this study was to delineate the relationship between positive, negative, cognitive, depressive, and excitement symptom dimensions of schizophrenia and cognitive functioning. Fifty-eight patients with schizophrenia (DSM-IV criteria) were assessed using the Positive and Negative Syndrome Scale (PANSS) and a battery of neuropsychological tests (executive function/abstraction, verbal and spatial working memory, verbal and nonverbal memory/learning, attention, visuospatial ability, and psychomotor speed). The cognitive symptom dimension correlated with executive functions, attention, verbal memory, and spatial ability. Severity of the negative symptom dimension was related to impairment in the structure of the semantic knowledge system, verbal memory, and auditory attention. In contrast, severity of the positive symptom dimension correlated only with impairment in the structure of the semantic knowledge system, and psychomotor speed. Finally, severity of the depressive and excitement symptom dimension was not associated with cognition. Correlations between symptom dimensions and cognitive measures were at best modest. Severity of cognitive and negative symptoms was mainly correlated with deficits on executive functions, semantic memory, and verbal memory, while positive symptoms only with semantic memory. These correlations were modest, suggesting that psychopathology and cognitive deficits in schizophrenia are caused, at least partially, by distinct pathophysiological processes.     

Episodic memory in schizophrenic patients and their relatives

BACKGROUND: Memory dysfunction among healthy relatives of patients with schizophrenia suggests that genetic liability to the disorder can also be manifested as cognitive impairment. This study was designed to further elucidate the nature of the memory dysfunction being transmitted. METHOD: Memory function was assessed in 62 schizophrenic patients, 98 of their healthy relatives and 66 controls. Material-specific immediate/delayed recall and percentage retention were investigated using the Logical Memory and Visual Reproduction tests of the Wechsler Memory Scale (WMS). A third subtest of the WMS, the Associate Learning and a visual analogue of it, the Abstract Paired Associates, were used to measure verbal and visual learning. Current general intellectual function was assessed using a five-subtest short-form of the Wechsler Adult Intelligence scale-Revised (WAIS-R). RESULTS: Schizophrenic patients performed significantly worse than controls on nearly all measures. Their relatives also showed significant deficit on the immediate and delayed recall of the Logical Memory, immediate recall of the Visual Reproduction, and the Abstract Paired Associates tests. Logical memory was substantially more impaired than the other measures for both patients and relatives. The deficit in immediate recall of the Logical Memory remained significant even after excluding those relatives with an Axis I diagnosis and schizotypal personality disorder. These findings were despite the relatives having an equivalent level of general intellectual function to that of controls. CONCLUSION: Familial, presumed genetic, liability to schizophrenia may be expressed as dysfunction in verbal memory.