Working memory in siblings of schizophrenia patients

Working memory (WM) has hardly been explored in non-psychotic relatives of schizophrenic patients despite its potential suitability as a neurocognitive endophenotype. Indeed, WM modalities, components and processes have rarely been compared in the same group of relatives. The present study examined neurocognitive performance in healthy siblings of schizophrenic patients, including both spatial and verbal WM modalities and tests tapping maintenance (Spatial Span Backwards and CPT-IP d') and manipulative (Letters and Numbers Sequencing) WM processes. METHODS: 68 schizophrenia patients, 38 healthy siblings and 63 controls were assessed on IQ, attention, memory, WM, and executive functions. Cluster A symptoms were screened out in siblings and controls. RESULTS: Siblings had an intermediate performance between that of schizophrenic patients and controls. They performed worse than controls on IQ, LNS, animal naming, backwards spatial span, phonemic fluency, numbers d', and forward spatial span. DISCUSSION: Consistent with the WM literature in schizophrenia, both verbal and spatial WM differed significantly between siblings and controls, suggesting that WM deficits are modality independent. Our results failed to support the hypothesis that tests tapping WM manipulative processes heavily loading on DLFPC are quantitatively more impaired in relatives and, therefore, more sensitive to liability for schizophrenia. However, firm conclusions cannot be drawn until more studies assessing both maintenance and manipulative WM processes in relatives are available.     

精神分裂症患者与其健康同胞认知功能比较

目的比较精神分裂症患者、精神分裂症患者健康同胞及健康对照者在认知功能上的差异。方法100例精神分裂症患者（患者组）及其健康同胞100名（同胞组）,以及80名正常对照者（对照组）为研究对象,采用威斯康星卡片分类测验（WCST）、Stroop色词测验（SCWT）和言语流畅性测验（VFTr）来评定认知功能。比较各组在各个认知功能纬度方面差异。结果在WCST中,患者组及其同胞组的持续错误数均高于对照组（F=73．24,P〈0．01）;患者组持续错误数高于同胞组。在V丌中,患者组、同胞组和对照组差异无统计学意义。在SCWT,彩色文字阅读测验（Stroop—C）和彩色文字颜色阅读（Stroop—cw）测验,患者组和同胞组完成时间比对照组长（Stroop—C：F=49．20,P〈0．01;Stroop—CW：F=87．72,P〈0．01）;患者组完成时间比同胞组长。结论精神分裂症患者及其同胞均可能存在执行功能缺陷,精神分裂症患者的执行功能障碍较其同胞更为严重。     

首发精神分裂症患者神经认知功能的遗传学分析

目的 探索精神分裂症患者及其亲属共同存在的神经认知功能损害,并对22号染色体上儿茶酚氧位甲基转移酶(COMT)基因和脯氨酸脱氢酶(PRODH)基因的5个候选单核苷酸多态性(SNP)位点进行相关的遗传学分析。方法 采用14个神经心理测验(共29项)对235例首发精神分裂症患者(患者组)、322名未患病亲属(亲属组)和133名正常对照(正常对照组)进行有关智力、注意、记忆、言语功能和执行功能等评定,比较各组间的神经认知功能有无差异,并对上述神经认知功能测验与COMT和PRODH基因的5个候选SNP进行定量性状的传递不平衡测试。结果 (1)患者组所有测验的成绩均差于正常对照组,差异有显著性(P<0.01和P<0.05),而亲属组的记忆、注意、言语功能和执行功能界于患者与正常对照之间;(2)PRODH1 195G/A与即刻逻辑记忆测验(P=0.03)、言语流畅性测验的正确数(P=0.03)和连线测验B的犯规数(P=0.01)相关,PRODH1945G/A与数字符号测验(P:0.01)、连线测验A的错误数(P:0.02)、HANOI塔测验的总分(P=0.01)、威斯康星卡片分类测验(WCST)的总错误数(P=0.01)、WCST的非持续错误数(P:0.02)和WCST的总分类数(P=0.02)相关。结论 精神分裂症患者在记忆、注意、言语功能和执行功能等方面存在广泛的神经认知功能损害,这种损害可能是精神分裂症的遗传“内表     

Temperament and character as schizophrenia-related endophenotypes in non-psychotic siblings

BACKGROUND: Quantitative endophenotypes are needed to better understand the pathogenesis of schizophrenia. The psychobiological model of temperament and character suggests that personality traits are heritable and regulated by brain systems influencing schizophrenia susceptibility. Thus, measures of temperament and character may serve as schizophrenia-related endophenotypes in individuals with schizophrenia and their non-psychotic siblings. METHODS: Individuals with schizophrenia (n=35), their non-psychotic siblings (n=34), controls (n=63), and their siblings (n=56) participated in a study of the clinical, neurocognitive and neuromorphological characteristics of schizophrenia. A mixed-model approach assessed group differences on the Temperament and Character Inventory (TCI). Neurocognitive deficits and psychopathology were correlated with the TCI. Configurations of TCI domains were examined using a generalized linear model. RESULTS: Individuals with schizophrenia and their non-psychotic siblings had higher harm avoidance than controls and their siblings. Individuals with schizophrenia had lower self-directedness and cooperativeness, and higher self-transcendence than their non-psychotic siblings, controls, and the siblings of controls. Neurocognition was not related to temperament and character in individuals with schizophrenia or either control group. In non-psychotic siblings, self-directedness and cooperativeness were correlated with working memory and crystallized IQ. CONCLUSION: Evidence supports harm avoidance as a schizophrenia-related endophenotype. An increased risk of schizophrenia may be associated with asociality (configured as high harm avoidance and low reward dependence), schizotypy (configured as low self-directedness, low cooperativeness, and high self-transcendence), and neurocognitive deficits (poor executive functioning, working/episodic memory, attention, and low IQ). The non-psychotic siblings demonstrated features of a mature character profile including strong crystallized IQ, which may confer protection against psychopathology.     

Neuropsychological functioning among non-psychotic siblings and parents of schizophrenic patients

Several studies have shown subtle neuropsychological deficits in healthy relatives of schizophrenic patients. However, older relatives and parents have been less frequently assessed than younger adult relatives and siblings. Furthermore, some areas of neuropsychological functioning such as memory and learning have been little studied. Thirty-seven 22-70-year-old non-psychotic parents and siblings of schizophrenic patients were compared to 37 healthy control subjects on a battery of neuropsychological tests (Trail Making, parts A and B, verbal fluency, Wisconsin Card Sorting Test, and four subtests of the Wechsler Memory Scale-Revised: logical memory, design reproduction, verbal paired associates and digit span). Relatives did not differ from control subjects on Wisconsin Card Sorting Test performance and on visual memory, but were significantly impaired on verbal fluency; more subtle deficits were found on Trail Making, part B, digit span and paired associates. A higher proportion of relatives than control subjects showed impairment on verbal fluency and verbal memory. These neuropsychological weaknesseswere present as much in siblings as in parents of schizophrenic patients, and age did not cancel differences between relatives and control subjects. Thus, these subtle deficits seem to be potential phenotypic markers of schizophrenia.     

Executive and amnestic functions of a group of first-degree relatives of schizophrenic patients

Several lines of evidence seem to indicate that some neurocognitive measures could be phenotypic markers of predisposition to schizophrenia. The aim of this study was to investigate 21 patients with schizophrenia, 51 of their first-degree relatives and 46 nonpsychiatric controls, with a series of tests known to be sensitive to prefrontal cortical damage--the Trail Making Test, part B (TMT B), the Wisconsin Card Sorting Test (WCST) and a verbal fluency test (VFT)- and/or sensitive to temporo-hippocampic dysfunctions: verbal and visual memory and verbal learning tests from the Wechsler Memory Scale-Revised (Wechsler, 1987). Since parents and siblings share on average 50% of their genes with the schizophrenic proband, firstly we predicted that the first-degree relatives' performance would be at an intermediate level between patients and control subjects and secondly, we expected that a higher proportion of relatives than of control subjects would be impaired. The patients demonstrated deviant patterns of neuropsychological performance on the three tests sensitive to frontal dysfunctions and on most of the memory and learning tests. In the relative group, performance on the TMT B, VFT, immediate verbal recall and verbal learning was at an intermediate level between both other groups and significantly impaired compared to control subjects. However, the relative group did not differ from the control group on the WCST, immediate visual recall, and delayed verbal and visual recalls. Furthermore, compared to the control group, the percentages of patients and relatives who scored one standard deviation below the mean control group were significantly higher for the VFT and immediate verbal recall scores. Among all the tests studied, the verbal fluency and the immediate verbal recall appeared to be valuable phenotypic markers of schizophrenia since: (i) their mean scores were poorer in the patient and in the relative groups, (ii) the percentages of patients and relatives with poor performance were higher than the percentage of controls, (iii) these deficits were not due to poorer general intellectual abilities in the relative group, (iv) these deficits did not correlate with anxiety or depression scores.     

A five-year longitudinal study of the regional cerebral metabolic changes of a schizophrenic patient from the first episode using Tc-99m HMPAO SPECT

This is a naturalistic study of the relationship between cerebral metabolic activity, clinical symptoms and treatment response in a schizophrenic patient for 5 years from the onset of her illness. Serial technetium-99m-HMPAO brain SPECT was used to measure regional cerebral metabolism. The Cambridge Neurological Inventory and neuropsychological tests (WAIS-R verbal subscales, Wisconsin Card Sorting Test, semantic verbal fluency, logical memory in Weschler Memory Scale) were used for neurocognitive assessment. Under-activity of the left temporal area was observed in the course of patient illness despite remission of the psychotic symptoms. Bilateral prefrontal metabolic under-activity was noted at the emergence of negative symptoms, executive neurocognitive dysfunction and the treatment-resistant state. After response to clozapine, the right prefrontal activity returned to a normal level. Our findings suggested that persistent left temporal under-activity detected by SPECT despite clinical remission may indicate a vulnerability for further relapses and development of a treatment-resistant state. Treatment-resistant state, negative symptoms and executive neurocognitive deficit may involve abnormal prefrontal metabolic activity and can be alleviated in clozapine-responsive patients. Received: 10 August 1998 / Accepted: 7 December 1999     

Clinical features of illness in siblings with schizophrenia or schizoaffective disorder

Evidence implicating genetic or prenatal-perinatal environmental causes in the familial aggregation of schizophrenia led us to study 53 sets of siblings, two or more of whom had chronic psychosis, either schizophrenia or schizoaffective disorder. We looked for similarities in clinical features and concordance of diagnosis within sibships to test for shared familial causes. Clinical variables, including diagnosis, specific symptoms, age at onset, and nongenetic perinatal factors, were studied. Auditory hallucinations, paranoid delusions, thought disorder, negative symptoms, and poor premorbid social adjustment did not significantly correlate in siblings. Concordance was found for schizoaffective disorder and history of major depressive episodes, suggesting that schizophrenia with a depressive component and Research Diagnostic Criteria schizoaffective illness may represent a specific etiologic subtype(s) of the illness, whereas the other noted symptoms may represent the variable expression of the disorder. Age at onset and at first hospitalization were significantly correlated, consistent with genetic or other familial factors on time of onset. Birth complications were significantly more frequent among the schizophrenic compared with non-psychotic siblings, had a familial component, and tended to be associated with an earlier age at onset. Thus, nongenetic perinatal factors may increase the risk for schizophrenia in a familial form of the illness and contribute to the correlation of ages at onset in siblings.     

Social cognitive problem-solving in schizophrenia: associations with fluency and verbal memory

This study assessed the relationship between social functioning and neurocognitive function in individuals with schizophrenia. Social cognitive problem-solving (SCPS) is a significant contributor to social competence and is an aspect of information processing that is involved in the identification and resolution of interpersonal or social problems. We examined 49 schizophrenia patients and 28 healthy controls using the means-ends problem-solving procedure (MEPS) for SCPS, the Rey Auditory Verbal Learning Test (RAVLT), the Wisconsin Card Sorting Test (WCST), and a series of fluency tests for neurocognitive assessment, as well as the Positive and Negative Syndrome Scale (PANSS) and the Global Assessment of Functioning (GAF). Fluency tests can be used to evaluate divergent thinking, and a qualitative analysis was done of the fluency test responses. The results suggest that patients with schizophrenia have a significantly poorer MEPS performance than normal controls. In patients with normal RAVLT scores, MEPS scores were correlated with task-modified responses on the fluency test but not with any of the WCST scores. This suggests that SCPS is related to divergent thinking that requires concept flexibility and/or the conversion of viewpoint in patients with schizophrenia in whom verbal memory function is preserved.     

Impact of coexistent schizotypal personality traits on frontal lobe function in obsessive-compulsive disorder

OBJECTIVE: This study was a post-hoc analysis of the results from a neuropsychological battery which was conducted to investigate the frontal lobe difference between obsessive-compulsive disorder (OCD) patients with and without schizotypal personality trait (SPT), especially dorsolateral prefrontal and medial frontal functions. METHODS: Fifty-five OCD patients were divided into two groups according to their Personality Disorder Questionnaire-4+ scores. Patients with OCD with SPT (n=17) and OCD without SPT (n=38) were compared to 52 schizophrenia patients and 67 healthy subjects. Two neuropsychological tasks, the Wisconsin Card Sorting Test (WCST) and verbal fluency tests which are considered to reflect dorsolateral and medial frontal functions, were selected for an analysis. RESULTS: OCD with SPT patients and patients with schizophrenia performed significantly worse than controls in both the WCST and verbal fluency tasks, whereas OCD without SPT patients showed no deficits in the same tasks. Moreover, we found no statistically significant difference in either task between patients having OCD with SPT and patients with schizophrenia. CONCLUSION: This study indicate that OCD with SPT may have distinct patterns of neurocognitive deficit that differ from those of OCD without SPT, especially in terms of frontal lobe function.     

Cognitive functioning in siblings discordant for schizophrenia

OBJECTIVE: The objective of this study was to investigate neuropsychological impairment as a genetically mediated risk indicator for schizophrenia while accounting for prevalence of schizotypy signs/symptoms in siblings. METHOD: Cognitive functioning in 25 individuals with schizophrenia, 25 unaffected siblings and 25 unrelated healthy controls, was assessed using neuropsychological tests of sustained attention, memory and learning, executive function, visual-spatial ability and psychomotor performance. RESULTS: Unaffected siblings demonstrated better performance than patients on some measures of memory and learning and executive function. Patients and siblings demonstrated impaired Full Scale IQ and verbal fluency, otherwise siblings performed similarly to healthy controls. Controlling for differences in IQ, the shared deficit in verbal fluency disappeared. CONCLUSION: Patients with schizophrenia and unaffected siblings (without schizotypy personality disorder) shared a neuropsychological deficit in verbal fluency. This deficit appeared to be mediated by IQ. Deficits, which differentiated patients from controls, may not be inherited and perhaps are related to the manifestation or treatment of schizophrenia.     

Cingulate gyrus neuroanatomy in schizophrenia subjects and their non-psychotic siblings

BACKGROUND AND METHODS: In vivo neuroimaging studies have provided evidence of decreases in the gray matter volume of the cingulate gyrus in subjects with schizophrenia as compared to healthy controls. To investigate whether these changes might be related to heritable influences, we used high-resolution magnetic resonance imaging and labeled cortical mantle distance mapping to measure gray matter volume, as well as thickness and the area of the gray/white interface, in the anterior and posterior segments of the cingulate gyrus in 28 subjects with schizophrenia and their non-psychotic siblings, and in 38 healthy control subjects and their siblings. RESULTS: There was a significant effect of group status on posterior cingulate cortex (PCC) gray matter volume (p=0.02). Subjects with schizophrenia and their non-psychotic siblings showed similar reductions of gray matter volume (~10%) in the PCC compared to healthy control subjects and their siblings. In turn, trend level effects of group status were found for thickness (p=0.08) and surface area (p=0.11) of the PCC. In the combined group of schizophrenia subjects and their siblings, a direct correlation was observed between PCC gray matter volume and negative symptoms. However, the reduction in PCC gray matter volume in schizophrenia subjects and their siblings was proportionate to an overall reduction in whole cerebral volume, i.e., the effect of group on the volume of the PCC became non-significant when cerebral volume was included as a covariate (p=0.4). There was no significant effect of group on anterior cingulate cortex volume, thickness, or area. CONCLUSIONS: Our findings suggest that decreases in the gray matter volume of the PCC occur in schizophrenia subjects and their siblings. The presence of such decreases in the non-psychotic siblings of schizophrenia subjects suggests that heritable factors may be involved in the development of cortical abnormalities in schizophrenia.     

Fronto-temporal function may distinguish bipolar disorder from schizophrenia

OBJECTIVES: There is evidence for differential neural alterations within the prefrontal cortex (PFC) in bipolar disorder I (BDI) and schizophrenia that may translate into different cognitive deficits. Our objective was to compare the cognitive profile of stable BDI and schizophrenic patients using neuropsychological tasks which utilize frontal systems but differ in terms of the exact neural circuits and cognitive processes involved. METHODS: We studied 43 patients with BDI, 54 with schizophrenia and 46 matched healthy participants. All participants completed (i) the Wisconsin Card Sorting Test (WCST) which is known to recruit the dorsal and ventral PFC, (ii) the verbal fluency task (VFT), which engages frontal-temporal regions, and (iii) the Stroop Colour Word Test (SWCT) which depends on the integrity of the cingulo-frontal network. A series of multivariate analyses examined differences between the cognitive profiles of BD and schizophrenic patients relative to that of healthy participants controlling for general intellectual ability and gender. RESULTS: Bipolar disorder I patients showed minimal verbal fluency impairment while schizophrenic patients demonstrated marked deficits on this task relative to the control and BDI groups. The two patient groups had comparable performance on the WCST. In the SWCT, schizophrenic patients showed impairment in both congruent and incongruent conditions while BD patients had deficits only in the latter. CONCLUSIONS: Absence of significant verbal fluency abnormalities and by inference dysfunction in the associated fronto-temporal circuitry may distinguish BDI from schizophrenia. Both disorders may show impairment in tasks involving cingulo-frontal networks with evidence of greater cingulate dysfunction in schizophrenia.     

Both processing speed and semantic memory organization predict verbal fluency in schizophrenia

We systematically examined the relationship of both lexical retrieval and semantic memory organization to categorical verbal fluency performance in 40 outpatient schizophrenic subjects and 16 healthy controls. Mean choice reaction time (RT) on a lexical decision task was used as a measure of lexical retrieval efficiency. The complexity of semantic memory organization was measured using a Pathfinder semantic network analysis (calculated as the number of inter-node links obtained from a similarity rating task). In the schizophrenia group only, RT and semantic network links were each significantly negatively correlated with fluency and, together, accounted for 23% of the variance in fluency. RT and links were not significantly correlated with one another. Findings were unrelated to age, sex, education, or medication dose. Controlling for IQ reduced but did not abolish the relationship between fluency and network links. We conclude that the restricted verbal output of schizophrenic subjects is related both to impaired lexical retrieval and to variation in semantic memory organization, which partly reflects general intelligence. The statistical independence of the retrieval speed and organizational factors suggests that individuals with schizophrenia differ in the underlying processes that contribute to their reduced verbal fluency.     

Familial resemblance for executive functions in families of schizophrenic and bipolar patients

Executive dysfunctions are considered to be putative markers of familial/genetic vulnerability to both schizophrenia and bipolar disorder. However, familial resemblance must be demonstrated before executive functions are used as a potential endophenotype. The aim of this study was to investigate familial resemblance for executive functions in families of schizophrenic and bipolar subjects. We assessed executive functions by means of two tests - the Wisconsin Card Sorting Test (WCST) and the Trail Making Test (TMT) - in 351 subjects from five populations: schizophrenic patients, bipolar patients, a group of relatives for each patient group and controls. For both tests, cognitive assessment results were consistent with previous studies: schizophrenic patients showed the greatest impairment, followed by bipolar patients and then the two groups of relatives. In families of bipolar patients we observed familial resemblance for the WCST and part A and part B of the TMT. However, by contrast with the classical point of view, considering executive measures to be markers of genetic vulnerability to schizophrenia, we did not demonstrate familial resemblance for either of the two executive tests in families of schizophrenic patients. Thus, executive measures, as assessed by the WCST or the TMT, should not be used as endophenotypes in genetic studies of schizophrenia unless confounders are identified and their effects eliminated.     

Soft neurological signs in schizophrenic patients and their nonpsychotic siblings

This study examined neurological signs as familial vulnerability factors to schizophrenia. Fifteen Chinese schizophrenic patients, 21 of their nonpsychotic siblings, and 26 healthy volunteers, matched for age, sex, and education, were assessed by using the Cambridge Neurological Inventory. Results showed that patients and their siblings had significantly higher global neurological impairment than controls. The severity of motor coordination impairment of the siblings was in between patients and controls. This may suggest either patients have higher genetic vulnerability for the neurological abnormality and schizophrenia than their nonpsychotic siblings or the disease can further worsen the preexisting neurological deficit. Disinhibition signs were similar in patients and siblings, but significantly less in controls indicating its familial nature. Extrapyramidal and sensory integration signs were similar in siblings and controls, but significantly more severe in patients, suggesting nonfamilial abnormalities. In conclusion, these findings may imply different etiological origins for different subgroups of neurological signs.     

The effect of previous psychotic mood episodes on cognitive impairment in euthymic bipolar patients

OBJECTIVES: Cognitive dysfunctions in several domains were proposed to be trait markers of bipolar patients. The aim of this study was to evaluate the effect of previous psychotic features on neuropsychological measures, including sustained attention, in remitted bipolar patients. METHODS: The study participants were 40 euthymic psychotic, 25 non-psychotic bipolar I patients and 30 healthy control subjects. Participants were assessed with a battery of neuropsychological tests targeting attention, executive functions, psychomotor speed, verbal learning and memory. RESULTS: Euthymic psychotic bipolar patients performed worse than controls on most of the measures, after controlling for the confounding effects of education, age and residual symptoms. Non-psychotic patients were also impaired on tasks of attention, fluency and psychomotor speed. 'Number of Wisconsin Card Sorting Test (WCST) categories' achieved was the only measure on which psychotic patients performed significantly worse compared to non-psychotic patients. Differences among patient groups were not explained by illness severity measures. The duration of illness was related to slowness in psychomotor speed tasks. Verbal memory deficits may be related to serum lithium levels and age of onset of disease. CONCLUSIONS: Deficits in cognitive flexibility may be a candidate for being a trait marker of psychotic features among bipolar patients. However, verbal fluency, psychomotor speed and sustained attention deficits may be candidates for vulnerability indicators of bipolar disorder in general.     

Prospective memory in patients with first-onset schizophrenia and their non-psychotic siblings

This behavioral study used a dual-task paradigm to compare PM performance in 35 patients with first-onset schizophrenia, 40 non-psychotic siblings and 35 healthy controls. It aimed specifically to examine the effect of schizophrenia group status on PM, the differential effect of group status on PM type, and correlations between PM and other neurocognitive functions and clinical data in first-onset schizophrenia. It also aimed to test the hypothesis that non-psychotic siblings had poorer PM performance than controls. The cohort of first-onset schizophrenia patients had relatively short illness durations (M = 1.7 years). The three groups of participants were matched in terms of age, gender and years of education. Results of the study confirmed that first-onset schizophrenia status had a primary effect on PM after controlling for other neurocognitive functions. We also found that first-onset schizophrenia status did not differentially affect two different types of PM. In the first-onset schizophrenia cohort, PM was found to correlate significantly with IQ, executive functions and sustained attention. Finally, contrary to the findings of the previous study, this study did not find siblings of schizophrenia patients to have impaired PM. Taking into account the previous findings of PM in chronic schizophrenia, we concluded that schizophrenia has a primary effect on PM regardless of illness duration.     

Volumetric analysis of frontal lobe regions in schizophrenia: relation to cognitive function and symptomatology.

BACKGROUND: The purpose of this study was to examine the structure of dorsolateral, medial, and orbital regions of the frontal lobe in schizophrenia, and to determine whether their volumetric measurements were related to cognitive function and symptomatology. METHODS: High resolution magnetic resonance imaging scans of the brains of 14 schizophrenic patients and 14 closely matched healthy controls were acquired. Volumes of gray and white matter of the left and right dorsolateral, medial, and orbital prefrontal brain regions were measured. Tests of verbal and visual memory and executive functions were used to assess cognitive function. The SANS and SAPS were used to obtain symptom ratings in patients. RESULTS: Data of 13 schizophrenic patients were analyzed. Patients showed a general, though not significant, decrease in volumes of frontal regions as compared to controls. In patients, but not in controls, smaller left and right prefrontal gray matter volumes were significantly correlated with impaired performance on immediate recall in verbal and visual memory and semantic fluency. Furthermore, in patients, smaller total orbitofrontal gray matter volume was significantly correlated with more severe negative symptomatology (rs = -.76, p = .006). CONCLUSIONS: These findings suggest that in schizophrenia, deficits in verbal and visual memory and semantic fluency and negative symptoms may be related to (subtle) abnormalities in frontal lobe structure.     

Comorbid substance abuse and neurocognitive function in recent-onset schizophrenia

Despite the high prevalence of comorbid substance use disorder (SUD) up to 65% in schizophrenia there is still few knowledge about the influence of substance abuse on neurocognitive function. In a prospective design we recruited 68 patients (aged 18–40 years) diagnosed as recent-onset schizophrenia or schizoaffective disorder consecutively admitted to hospital. The patients received standardized psychopathological evaluation of schizophrenic symptoms [Brief Psychiatric Rating Scale (BPRS), Scale for the Assessment of Negative Symptoms (SANS)], depressive symptoms [Montgomery Asberg Depression Rating Scale, (MADRS)] and global ratings [Clinical Global Impressions Scale (CGI), Global Assessment of Functioning Scale (GAF)]. Out of this sample 44 subjects underwent after stabilization (4–6 weeks after admission) neuropsychological investigation focusing on early information processing (Trail-Making-Test A, Digit Span), visuo-spatial ability (Corsi Block Tapping), verbal fluency (Verbal Fluency Test, semantic and letter category), and executive functioning and cognitive flexibility [Trail-Making-Test B, Wisconsin Card Sorting Test (WCST)]. About 36% of patients reported drug abuse [European Addiction Severity Index (EuropASI)] with a high prevalence for cannabis. Compared with nonabusers the sample of substance abusers was younger, predominantly male and had lower socioeconomic status. Attentional impairment according to the SANS subscale was less in abusers than in nonabusers on admission, no other psychopathological differences could be detected. Schizophrenic patients without substance abuse demonstrated significantly better performance only in a few neurocognitive tasks (Verbal Fluency, letter category and at trend level Digit Span, backwards), while there tended to be an advantage for substance abusers in executive functioning (WCST, not significant). These results are consistent with other studies of first-episode patients. The lack of higher cognitive disturbance in young schizophrenic patients with comorbid substance abuse may encourage clinicians to develop integrated treatment programmes using cognitive strategies of drug therapy.