Cognitive deficits and levels of IQ in adolescent onset schizophrenia and other psychotic disorders

Cognitive deficits have been found to be prevalent in early onset schizophrenia. Whether these deficits also characterise other early onset psychotic disorders to a similar degree is unclear, as very few comparative studies have been done. The primary purpose of this study was to compare the profile and severity of cognitive impairments in first-episode early onset psychotic patients who received the schizophrenia diagnosis to those diagnosed with other non-organic, non-affective psychotic disorders. The secondary purpose was to examine whether the profile of cognitive deficits, in terms of intelligence, executive functions, memory, attention and processing speed was global or specific. First-episode psychotic adolescents (N = 39) between the ages 11 and 17 years were included, 18 of whom were diagnosed with schizophrenia, and 21 with other non-organic, non-affective psychoses, using ICD-10 criteria. A healthy control group (N = 40) was included, matched on gender and age. Cognitive functions were assessed using WISC-III/R, the CANTAB battery, WCST, Trail Making B, fluency tasks, and Buschke's selective reminding task. A similar profile and level of impairment was found on measures of attention, executive functions, reaction time, and memory in the schizophrenic and psychotic adolescent groups. However, analyses of WISC-III factor profiles suggested that early onset schizophrenia patients may have more global IQ deficits than non-organic, non-affective psychoses when examined recently after illness onset. Compared to the deficits of adult schizophrenia described in the literature, the results suggest relatively spared simple reaction times in early onset patients.     

Cognitive dysfunction in adult males with non-syndromic clefts of the lip and/or palate

Cognitive deficits have been well-documented in children with non-syndromic clefts of the lip and/or palate. However, no study to date has formally assessed cognition in adults with oral clefts. This study was designed to evaluate neuropsychological functioning in adult males with non-syndromic clefts of the lip and/or palate (n=50) compared to age and sex-matched controls.Subjects with oral clefts were found to have significantly lower full scale IQ, performance IQ and verbal IQ scores compared to their matched controls. After controlling for IQ, patients showed specific deficits in verbal fluency.Adult males with oral clefts manifest a specific pattern of cognitive deficits. As the development of the face is highly interdependent with the development of the brain, it is theorized that the etiology of these cognitive deficits is a primary problem with abnormal brain development.     

Intelligence in schizophrenia: meta-analysis of the research

This article combines a review and meta-analysis of research on IQ in schizophrenia, with emphasis on areas of convergence in the findings, as well as questions that remain to be answered. Taken together, the findings suggest that early-onset and adult-onset schizophrenia are associated with intellectual deficits across the lifespan. Preschizophrenic children, adolescents, and young adults perform below matched controls on a variety of standardized measures of intelligence. Significant IQ deficits are also apparent after the onset of the disorder. Moreover, IQ is positively related to several indices of prognosis, and, among hospitalized patients, there is negative within-subject covariance between intellectual performance and symptom severity. Although there is fairly consistent evidence that Verbal IQ is higher than Performance IQ among schizophrenic patients, a more specific pattern of subtest performance is not apparent. A central question raised by the results is whether IQ is an independently determined factor that can serve to mitigate the vulnerability of individuals who are constitutionally predisposed to schizophrenia, or whether intellectual deficit is one manifestation of the constitutional predisposition to the disorder. The findings also raise the question of possible sex differences in the developmental determinants of schizophrenia: Meta-analyses revealed that premorbid IQ deficits are more prevalent among males than females.     

Neuropsychological assessment of adult patients with attention-deficit/hyperactivity disorder

Adults with persistent attention-deficit/hyperactivity disorder (ADHD) may show cognitive deficits as compared to healthy control subjects. The aim of this study was to compare a sample of adult outpatients with ADHD on medication to healthy controls on a comprehensive neuropsychological assessment battery. Thirty adults with ADHD under stable psychopharmacological treatment and 27 healthy controls matched for age, gender, and IQ were assessed with ten tests measuring performance with regard to attention, memory, executive function, and fine motor control. Lower performance in patients as compared to controls was found in tests of verbal and visual memory, speed of visuo-motor search, set shifting, and divided attention. Indicators of response inhibition and simple response speed were less affected. Adults with ADHD show indicators of lowered cognitive performance under medication. These are related more to memory and attention under high mental load than to response inhibition or simple attention or motor performance.     

The relationship between IQ, memory, executive function, and processing speed in recent-onset psychosis: 1-year stability and clinical outcome

Studies commonly report poor performance in psychotic patients compared with controls on tasks testing a range of cognitive functions, but, because current IQ is often not matched between these groups, it is difficult to determine whether this represents a generalized deficit or specific abnormalities. Fifty-three first-episode psychosis patients and 53 healthy controls, one-to-one matched for sex, age, and full-scale current IQ, were compared on Wechsler Adult Intelligence Scale (WAIS) subtests representing indices of perceptual organization, verbal comprehension, processing speed, and working memory as well as other tests of executive function and episodic memory. The groups showed an equivalent pattern of performance on all WAIS subtests except digit symbol processing speed, on which the patients were significantly worse. Patients were also worse on measures where performance correlated with digit symbol score, namely working and verbal memory tasks. Standardized residual scores for each subtest were calculated for each patient using the difference between their actual subtest score and a predicted subtest score based on their full-scale IQ and the performance of controls. Scaled scores and residual scores were examined for relationships with clinical measures. Digit symbol-scaled score was significantly correlated with concurrent negative syndrome score at baseline, and digit symbol residual score significantly predicted residual negative symptoms at 1-year follow-up. In summary, our comparison of patients and controls precisely matched for IQ revealed that processing speed was attenuated in recent-onset schizophrenia, contributed significantly to working and episodic memory deficits, and was a prognostic factor for poor outcome at 1 year.     

Cognitive deficits in children with sickle cell disease

We tested a hypothesis that children with sickle cell disease who are completely normal by magnetic resonance imaging can still be cognitively impaired, as predicted by a model of diffuse brain injury. Fifty-four patients with hemoglobin SS (average age 10.9 years +/- 2.9 years SD) were examined with the Wechsler Intelligence Scale for Children-III (WISC-III) and were randomly matched by age, race, and gender with healthy children from the Wechsler normative database. Patients were also imaged at 1.5 Tesla with standard imaging sequences. Among 30 patients who were normal by magnetic resonance imaging, there were substantial deficits in Wechsler Full-Scale IQ, Verbal IQ, and Performance IQ (all P < .01) compared with African-American controls. The patient Wechsler Full-Scale IQ was 12.9 points lower than that of controls and decreased as a function of age (probability = .014). The findings suggest that there is diffuse brain injury in patients and that patient deficits increase with age.     

Intelligence in children with hydrocephalus, aged 4-15 years: a population-based, controlled study

The aim of this population-based study is to investigate IQ and IQ-related factors in children with hydrocephalus (HC). Psychometric intelligence was assessed in subjects below the age of 7.3 years (N=52, F=18, M=34) with the Wechsler Preschool and Primary Scale of Intelligence - Revised (WPPSI-R) and for children above the age of 7.3 years (N=29, F=6, M=23) with the Wechsler Intelligence Scale for Children - Revised (WISC-R). The controls were matched according to age, gender, and geographic variables. All children were living in western Norway. 57 children had infantile HC (IH) and 24 had childhood HC (CH). Children with myelomeningocele (MMC), traumatic brain injury (TBI), or intracranial tumours were excluded. IQ levels were found to be significantly higher in the control group than in the HC groups. The Kaufman factors showed a similar pattern, with lowest values in IH, and CH intermediate between IH and NC. The results demonstrate that HC affects IQ. More specific cognitive profiles, such as non-verbal learning disabilities, are not detectable when using the Wechsler tests. For this purpose, other tests and models for analyses may be recommended.     

Theory of mind deficits in chronic schizophrenia: evidence for state dependence

There is evidence that people with schizophrenia show specific deficits in theory of mind (ToM). However, it is a matter of debate whether these are trait or state dependent, and the nature of the relationship between ToM deficits and particular symptoms is controversial. This study aimed to shed further light on these issues by (1) examining ToM abilities in 61 individuals with chronic schizophrenia during a stable phase as compared with 51 healthy controls matched by gender, age, educational level and current IQ, and (2) exploring the relationship between ToM and symptoms. Second order verbal stories and a non-verbal picture-sequencing task were used as ToM measures. Results showed no differences in ToM performance between patients and controls on either measure. Subsequent subgrouping of patients into remitted and non-remitted showed a worse performance of non-remitted patients only on second order ToM tasks. Specific ToM deficits were found associated with delusions. Association with negative symptoms was found to be less specific and accounted for by illness chronicity and general cognitive impairment. The results from the present study are in line with models which hypothesise that specific ToM deficits in schizophrenia are state dependent and associated with delusions. Such associations may also be task specific.     

Early Childhood IQ Trajectories in Individuals Later Developing Schizophrenia and Affective Psychoses in the New England Family Studies

Individuals who develop schizophrenia in adulthood exhibit, on average, deficits in childhood cognition relative to healthy controls. However, it remains unclear when in childhood such deficits emerge and whether they are stable across childhood or change (increase or decrease) across development. Importantly, whether the trajectory of childhood cognition differs among youth who later develop affective psychoses (AP) vs schizophrenia as adults remains unresolved. Subjects in the Collaborative Perinatal Project were administered the Stanford-Binet IQ test at age 4 and the Wechsler Intelligence Scale for Children at age 7. A total of 9809 (54.7%) participants in the New England Study sites were tested at both ages, including 37 who later developed schizophrenia spectrum psychoses (SSP) and 39 who later developed AP. Logistic regression models examined the association of level of and change in childhood IQ and later SSP or AP. Lower overall childhood IQ was associated with higher risk of SSP. Additionally, there was a small mean increase in IQ in the SSP group relative to a mean decrease in the control group from age 4 to 7 such that positive change in IQ was significantly associated with a higher risk of SSP. Neither overall level nor change in IQ was associated with risk of AP. The results are consistent with neurocognitive impairment throughout early childhood specifically for children who later develop schizophrenia, affirming the theory of atypical neurodevelopment in premorbid schizophrenia.Key words: IQ, cognition, schizophrenia, affective psychosis, cognitive development     

Predictors and Correlates of Adaptive Functioning in Children with Developmental Disorders

Autism is a developmental disorder marked by impairments in socialization, communication, and perseverative behavior and is associated with cognitive impairment and deficits in adaptive functioning. Research has consistently demonstrated that children with autism have deficits in adaptive functioning more severe than their cognitive deficits. This study investigates the correlates and predictors of adaptive functioning as measured by the Vineland Adaptive Behavior Scales in high- and low-functioning children with autism and their age and nonverbal IQ matched controls. Thirty-five 9-year-old children with high-functioning autism (HAD) were compared with 31 age-matched children with developmental language disorder (DLD), and 40 9-year-old children with low-functioning autism (LAD) were compared with 17 age-matched children with low IQ on adaptive functioning, IQ, autistic symptomology, and tests of language and verbal memory. Results indicate that both groups with autism were significantly impaired compared to their matched controls on Socialization and Daily Living, but not Communication and that these impairments were more pronounced in the HAD group than in the LAD group. Adaptive behavior was strongly correlated with autistic symptomology only in the HAD group. Regression analyses indicated that IQ was strongly predictive of adaptive behavior in both low-functioning groups, but tests of language and verbal memory predicted adaptive behavior in the higher functioning groups. Results suggest that IQ may act as a limiting factor for lower functioning children but higher functioning children are impaired by specific deficits, including autistic symptomology and impaired language and verbal memory.     

Precursors of cognitive impairments in psychotic disorders: A population-based study

Cognitive deficits have been found to be more prevalent in psychotic than in other disorders. Longitudinal research has shown that these deficits were generally already existent before onset of illness and are therefore not necessarily attributable to neurodegenerative processes. This study investigated whether both low IQ and markers of premorbid cognitive dysfunction independently contribute to an increased risk for psychoses. In a cross-sectional study about 50,000 young Swiss males completed a survey of intellectual problems in childhood/adolescence and other vulnerability factors during military call-up in 2005/2006. Subsequently, military IQ assessments were carried out on the entire sample. Diagnostic assessments were conducted according to International Classification of Diseases-10th edition (ICD-10). Low, especially performance, IQ was highly associated with an increased risk for psychotic disorders after adjusting for preexisting cognitive deficits and covariates, while in other disorders this association was less marked. Furthermore, preexisting intellectual problems emerged as important risk factors for psychoses. Our results confirm the importance of low IQ as characteristic of psychoses. Although premorbid intellectual deficits are common in people who go on to develop psychosis, neurodegenerative disease processes may also precipitate further declines in fluid cognitive functions. Assessment of cognitive functioning should be taken into account in early detection of psychoses.     

颞叶癫痫患者认知功能及相关因素的分析

目的分析颞叶癫痫患者认知功能的状况,并进一步探讨性别、病程、临床发作、神经电生理及药物等因素对患者认知功能的影响。方法从我院2002～2010年住院部中抽出符合入选标准的55例颞叶癫痫患者及随机抽取的同期48例健康对照者的韦氏成人智力量表、韦氏成人记忆量表、H.R.成人神经心理成套测验记录测验值进行回顾性分析。结果颞叶癫痫患者全量表智商(full intelligence quotient,FIQ)、记忆商(memory quo-tient,MQ)均明显低于健康对照者(P<0.001),脑病损程度(disease quotient,DQ)明显高于健康对照者(P<0.001)。不同文化程度的颞叶癫痫患者IQ、MQ、DQ有显著性差异,文化程度越高,其IQ及MQ越高(P<0.01),DQ越小(P<0.01);不同发作频率的颞叶癫痫患者IQ、MQ及DQ有显著性差异,发作越频繁,其IQ及MQ越低(P<0.01),DQ越高(P<0.01);不同脑电图异常改变的颞叶癫痫患者IQ、MQ和DQ有显著性差异,癫痫样放电越明显,其IQ及MQ越低(P<0.01),DQ越高(P<0.01)。多元逐步回归分析显示,影响患者IQ、MQ及DQ的因素依次为发作频率和脑电图癫痫样放电。结论颞叶癫痫患者存在不同程度的认知功能障碍。关注颞叶癫痫患者认知功能状况,尽早采取有效的治疗方法控制癫痫发作是避免和减少患者认知功能障碍,提高生活质量的重要前提。     

Neuropsychological functioning in nonmentally retarded autistic individuals.

To investigate several neurobiological theories we evaluated the neuropsychological functioning of 15 non-mentally retarded autistic adolescents and young adults and 15 controls matched on age, gender, IQ, and race. The autistic subjects were found to perform less well than controls on measures of abstraction involving cognitive flexibility, verbal reasoning, complex memory, and complex language comprehension in the absence of significant differences on measures of attention, associative memory, and the rule-learning aspects of abstraction. These findings are most consistent with a generalized abnormality in complex information processing and would not support theories purporting fundamental deficits in attention or information acquisition.     

Behaviour, attention and cognition in severe dyslexia

Information about coexisting problems in dyslexia may be vital for diagnostic and remedial procedures. There are few studies in this area, and to our knowledge none for the students in focus in this study. They all have phonological deficits and severely impaired reading abilities, in spite of prolonged educational remediation. The aim was to assess if these students have more behavioural/emotional problems than normal reading students. A clinical sample of 70 students, 59 males and 11 females, were compared to a normal reading control group. The groups were pair-wise matched on age, gender, cognitive level, and whether they lived in rural or urban areas. Mean age for the two groups was 150 months, and mean IQ scores approximately 100. Information on behaviour/emotions was obtained from parents, teachers and participants by means of the Child Behavior Checklist, Teacher's Report Form and Youth Self Report. The dyslexia group showed significantly more problems in all areas than the controls. This was reported from all three groups of informants. Parents reported most problems, internalizing behaviour for more than 50% of the participants and total problem behaviour for nearly 45%. Significantly more attention problems were also reported for the dyslexia group from all informants. Parents reported that nearly half the group demonstrated attention problems. Both groups of participants had more problems reported for those with IQ scores of 100 or lower. Further research is needed in this area, but the results clearly indicate that identifying additional behavioural/emotional problems may be imperative for students with severe reading problems.     

Neurological soft signs in juvenile patients with Asperger syndrome, early-onset psychosis, and healthy controls

Aim: The study of neurological soft signs (NSS) in patients with Asperger syndrome may help us to elucidate the neurological basis of this disorder and to clarify its relationship with other neurodevelopmental disorders. The goal of this study was to compare the prevalence of NSS in a sample of patients with Asperger syndrome, early-onset psychosis and healthy controls. Method: NSS were assessed by means of the Neurological Evaluation Scale in a sample of 29 patients with Asperger syndrome (mean age = 12.86 ± 2.58 years), 30 patients with first-episode early-onset psychoses (mean age 14.17 ± 1.02 years) and 30 healthy controls (mean age 12.33 ± 2.69 years). Results: Significant group differences were found between Asperger syndrome patients and healthy controls both in all the Neurological Evaluation Scale subscales and in the Neurological Evaluation Scale total score. There were no significant differences between both groups of patients in any of the Neurological Evaluation Scale scores. Conclusions: NSS are more prevalent in Asperger syndrome than in healthy controls. The NSS profile was not disorder-specific in our samples of patients with Asperger syndrome and early-onset psychoses.     

Humor perception deficits in schizophrenia

Humor is a complex cognitive process that could be used to elucidate subtle cognitive deficits. Significant deficits in humor perception were observed among 23 outpatients with schizophrenia compared with 20 controls matched for age, gender and education, using a 128-item humor test.     

Gender influences the detection of spatial working memory deficits in bipolar disorder

Objective:  Despite evidence that gender may influence neurocognitive functioning, few studies have examined its effects in bipolar disorder (BD) a priori . The aim of this study was to examine how gender influences executive-type functions, which are potentially useful as endophenotypes for BD.
Methods:  The performance of 26 euthymic patients (12 males, 14 females) with DSM-IV BD (20 BD type I and six BD type II) was compared to that of 26 controls (12 males, 14 females) on tests of executive function. Controls were matched to patients on an individual basis for sex, age and premorbid IQ. Tests assessed spatial working memory (SWM), planning, attentional set-shifting and verbal fluency.
Results:  Overall, patients showed deficits in SWM strategy (p < 0.001) and made more SWM errors relative to controls (p < 0.001). These deficits were more apparent in male-only comparisons (both p < 0.001) than in female-only comparisons (both p < 0.05). When examined in isolation, male controls were significantly better at performing the SWM task than female controls (both p < 0.05). This pattern was not observed in the patient cohort: male patients had poorer strategy scores than female patients (p < 0.05), but made a similar number of SWM errors.
Conclusions:  These findings provide evidence that gender can influence the detection of SWM deficits in the euthymic phase of BD, as the sex-related disequilibrium in SWM identified in healthy controls was disrupted in BD.     

Comparison of adult manifestations of schizophrenia with onset before and after 15 years of age

We examined 19 adult cases of early-onset schizophrenia (onset before age 15) and 19 controls (schizophrenia with onset between age 15 and 35). Being matched by sex, length of hospitalization and living environment while the present age between groups showed no difference, patients were compared on psychopathological symptom measures and intelligence quotient (IQ). Results showed that early-onset cases scored significantly higher on Scales for the Assessment of Negative Symptoms and had lower performance IQ. No group difference in positive symptoms measure from Brief Psychiatric Rating Scale and full IQ was noted. It suggested that when early-onset patients grew up, phenomenologically, they resembled the schizophrenia of usual early-adult onset in the positive symptom dimension, but with more negative symptoms, which may be fundamental in this group of patients.     

Neuropsychological functioning in nonmentally retarded autistic individuals

Abstract

To investigate several neurobiological theories we evaluated the neuropsychological functioning of 15 non-mentally retarded autistic adolescents and young adults and 15 controls matched on age, gender, IQ, and race. The autistic subjects were found to perform less well than controls on measures of abstraction involving cognitive flexibility, verbal reasoning, complex memory, and complex language comprehension in the absence of significant differences on measures of attention, associative memory, and the rule-learning aspects of abstraction. These findings are most consistent with a generalized abnormality in complex information processing and would not support theories purporting fundamental deficits in attention or information acquisition.     

Developmental trajectories of brain structure in adolescents with 22q11.2 deletion syndrome: a longitudinal study

The 22q11.2 deletion syndrome (22q11.2DS) is associated with very high rates of schizophrenia-like psychosis and cognitive deficits. Here we report the results of the first longitudinal study assessing brain development in individuals with 22q11.2DS. Twenty-nine children with 22q11.2DS and 29 age and gender matched controls were first assessed during childhood or early adolescence; Nineteen subjects with 22q11.2DS and 18 controls underwent follow-up during late adolescence-early adulthood. The 22q11.2DS subjects showed greater longitudinal increase in cranial and cerebellar white matter, superior temporal gyrus, and caudate nucleus volumes. They also had a more robust decrease in amygdala volume. Verbal IQ (VIQ) scores of the 22q11.2DS group that developed psychotic disorders declined significantly between assessments. Decline in VIQ in 22q11.2DS was associated with more robust reduction of left cortical grey matter volume. No volumetric differences were detected between psychotic and nonpsychotic subjects with 22q11.2DS. Brain maturation associated with verbal cognitive development in 22q11.2DS varies from that observed in healthy controls. Further longitudinal studies are likely to elucidate brain developmental trajectories in 22q11.2DS and their association to psychotic disorders and cognitive deficits in this population.