Memory generalization is selectively altered in the psychosis dimension

Global deficits in declarative memory are commonly reported in individuals with schizophrenia and psychotic bipolar disorder, and in their biological relatives. However, it remains unclear whether there are specific components within the global declarative memory dysfunction that are unique to schizophrenia and bipolar disorder, or whether these impairments overlap the two psychoses. This study sought to characterize differential components of learning and memory in individuals within the psychosis dimension: probands with schizophrenia (SZP, n=33), probands with psychotic bipolar I disorder (BDP, n=20), and biological relatives of SZP (SZR, n=21), contrasted with healthy controls (HC, n=26). A computerized cognitive paradigm, the Acquired Equivalence test, with probes for associative learning, memory for learned associations, and memory generalization was administered, along with standardized neuropsychological measures of declarative memory. All study groups were able to learn and remember the associations, although SZP were slower than HC in the initial learning stages. Both SZP (significantly) and BDP (at a trend level) showed altered memory generalization compared to HC (SZP vs. HC, p=.038, d=.8; BDP vs. HC, p=.069, d=.95). SZR showed memory generalization intermediate between SZP and HC, although their performance did not differ significantly from either group. These findings indicate that probands with schizophrenia and bipolar psychoses have similar alteration in the ability to flexibly generalize learned knowledge when probed with novel stimuli, despite overall sufficient associative learning and memory for what they learned. These results suggest that the two disorders present a clinical continuum with overlapping hippocampus-mediated memory generalization dysfunction underlying the psychosis phenotype.     

Reduced prepulse inhibition in adolescents at risk for psychosis: a 2-year follow-up study

Background

Reduced prepulse inhibition (PPI) of the auditory startle reflex is a hallmark feature of attention-processing deficits in patients with schizophrenia and other psychotic disorders. Recent evidence suggests that these deficits may also be present before the onset of psychosis in individuals at ultra-high risk (UHR) and become progressively worse as psychosis develops. We conducted a longitudinal follow-up study to observe the development of PPI over time in UHR adolescents and healthy controls.

Methods

Two-year follow-up data of PPI measures were compared between UHR adolescents and a matched control group of typically developing individuals.

Results

We included 42 UHR adolescents and 32 matched controls in our study. Compared with controls, UHR individuals showed reduced PPI at both assessments. Clinical improvement in UHR individuals was associated with an increase in PPI parameters.

Limitations

A developmental increase in startle magnitude partially confined the interpretation of the association between clinical status and PPI. Furthermore, post hoc analyses for UHR individuals who became psychotic between assessments had limited power owing to a low transition rate (14%).

Conclusion

Deficits in PPI are present before the onset of psychosis and represent a stable vulnerability marker over time in UHR individuals. The magnitude of this marker may partially depend on the severity of clinical symptoms.     

Comparison of the Heritability of Schizophrenia and Endophenotypes in the COGS-1 Family Study

Background:

Twin and multiplex family studies have established significant heritability for schizophrenia (SZ), often summarized as 81%. The Consortium on the Genetics of Schizophrenia (COGS-1) family study was designed to deconstruct the genetic architecture of SZ using neurocognitive and neurophysiological endophenotypes, for which heritability estimates ranged from 18% to 50% (mean = 30%). This study assessed the heritability of SZ in these families to determine whether there is a “heritability gap” between the diagnosis and related endophenotypes.

Methods:

Nuclear families (N = 296) with a SZ proband, an unaffected sibling, and both parents (n = 1366 subjects; mean family size = 4.6) underwent comprehensive endophenotype and clinical characterization. The Family Interview for Genetic Studies was administered to all participants and used to obtain convergent psychiatric symptom information for additional first-degree relatives of interviewed subjects (N = 3304 subjects; mean family size = 11.2). Heritability estimates of psychotic disorders were computed for both nuclear and extended families.

Results:

The heritability of SZ was 31% and 44% for nuclear and extended families. The inclusion of bipolar disorder increased the heritability to 37% for the nuclear families. When major depression was added, heritability estimates dropped to 34% and 20% for nuclear and extended families, respectively.

Conclusions:

Endophenotypes and psychotic disorders exhibit comparable levels of heritability in the COGS-1 family sample. The ascertainment of families with discordant sibpairs to increase endophenotypic contrast may underestimate diagnostic heritability relative to other studies. However, population-based studies also report significantly lower heritability estimates for SZ. Collectively, these findings support the importance of endophenotype-based strategies and the dimensional view of psychosis.Key words: schizophrenia, psychosis, endophenotypes, cognition, biomarkers, heritability     

Subjective Cognitive Complaints and Functional Disability in Patients With Borderline Personality Disorder and Their Nonaffected First-Degree Relatives

Objective:

To examine the contributions of subjective cognitive complaints to functional disability in patients with borderline personality disorder (BPD) and their nonaffected relatives.

Method:

Patients with BPD (n = 26), their first-degree biological relatives (n = 17), and nonpsychiatric control subjects (n = 31) completed a self-report measure of cognitive difficulties and rated the severity of their functional disability on the World Health Organization Disability Assessment Schedule 2.0.

Results:

After accounting for group differences in age and severity of depressive symptoms, patients and relatives endorsed more inattention and memory problems than control subjects. Whereas probands reported greater disability than relatives and control subjects across all functional domains, relatives described more difficulties than control subjects in managing multiple life activities, including domestic activities and occupational and academic functioning, and participating in society. For both probands and relatives, inattention and memory problems were linked primarily to difficulties with life activities, independent of depression and other comorbid psychiatric disorders.

Conclusions:

Problems with inattention and forgetfulness may lead to difficulties carrying out activities of daily living and occupational or academic problems in patients with BPD, as well as their nonaffected first-degree relatives.     

COMT,neuropsychological function and brain structure in schizophrenia: a systematic review and neurobiological interpretation

Background

Endophenotypes in genetic psychiatry may increase our understanding of the molecular mechanisms underlying disease risk and its manifestations. We sought to investigate the link between neuropsychological impairments and brain structural abnormalities associated with the COMT Val¹⁵⁸Met polymorphism in patients with schizophrenia to improve understanding of the pathophysiology of this disorder.

Methods

We performed a systematic review using studies identified in PubMed and MEDLINE (from the date of the first available article to July 2012). Our review examined evidence of an association between the COMT Val¹⁵⁸Met polymorphism and both neuropsychological performance and brain structure in patients with psychosis, in their relatives and in healthy individuals (step 1). The review also explored whether the neuropsychological tasks and brain structures identified in step 1 met the criteria for an endophenotype (step 2). Then we evaluated evidence that the neuropsychological endophenotypes identified in step 2 are associated with the brain structure endophenotypes identified in that step (step 3). Finally, we propose a neurobiological interpretation for this evidence.

Results

A poorer performance on the n-back task and the Continuous Performance Test (CPT) and smaller temporal and frontal brain areas were associated with the COMT Val allele in patients with schizophrenia and their relatives and met most of the criteria for an endophenotype. It is possible that the COMT Val¹⁵⁸Met polymorphism therefore contributes to the development of these neuropsychological and brain structural endophenotypes of schizophrenia, in which the prefrontal cortex may represent the neural substrate underlying both n-back and CPT performances.

Limitations

The association between a single genetic variant and an endophenotype does not necessarily imply a causal relationship between them.

Conclusion

This evidence and the proposed interpretation contribute to explain, at least in part, the biological substrate of 4 important endophenotypes that characterize schizophrenia.     

Nightmares in Patients With Psychosis: The Relation With Sleep,Psychotic, Affective,and Cognitive Symptoms

Objective:

To examine the prevalence of nightmares in people with psychosis and to describe the link between nightmares and sleep quality, psychotic, affective, and cognitive symptoms.

Methods:

Forty participants with psychotic symptoms completed an assessment of nightmares, sleep quality, positive symptoms of psychosis, affect, posttraumatic stress, social functioning, and working memory.

Results:

Among the patients, 55% reported weekly distressing nightmares. Experience of more frequent nightmares was related to poorer sleep quality and sleep efficiency. More distressing nightmares were positively associated with greater delusional severity, depression, anxiety, stress, and difficulties with working memory.

Conclusions:

Nightmares might be common in those with psychosis and are associated with increased day- and nighttime impairment. Future research should investigate treatments for nightmares, for people presenting with psychotic symptoms.     

Resting-state functional connectivity abnormalities in patients with obsessive–compulsive disorder and their healthy first-degree relatives

Background

Obsessive–compulsive disorder (OCD) is a common, heritable neuropsychiatric disorder, hypothetically underpinned by dysfunction of brain cortical–striatal–thalamic–cortical (CSTC) circuits; however, the extent of brain functional abnormalities in individuals with OCD is unclear, and the genetic basis of this disorder is poorly understood. We determined the whole brain functional connectivity patterns in patients with OCD and their healthy first-degree relatives.

Methods

We used resting-state fMRI to measure functional connectivity strength in patients with OCD, their healthy first-degree relatives and healthy controls. Whole brain functional networks were constructed by measuring the temporal correlations of all brain voxel pairs and further analyzed using a graph theory approach.

Results

We enrolled 39 patients with OCD, 20 healthy first-degree relatives and 39 healthy controls in our study. Compared with healthy controls, patients with OCD showed increased functional connectivity primarily within the CSTC circuits and decreased functional connectivity in the occipital cortex, temporal cortex and cerebellum. Moreover, patients with OCD and their first-degree relatives exhibited overlapping increased functional connectivity strength in the bilateral caudate nucleus, left orbitofrontal cortex (OFC) and left middle temporal gyrus.

Limitations

Potential confounding factors, such as medication use, heterogeneity in symptom clusters and comorbid disorders, may have impacted our findings.

Conclusion

Our preliminary results suggest that patients with OCD have abnormal resting-state functional connectivity that is not limited to CSTC circuits and involves abnormalities in additional large-scale brain systems, especially the limbic system. Moreover, resting-state functional connectivity strength abnormalities in the left OFC, bilateral caudate nucleus and left middle temporal gyrus may be neuroimaging endophenotypes for OCD.     

Reduced prepulse inhibition as an early vulnerability marker of the psychosis prodrome in adolescence

Background

The onset of psychosis is thought to be preceded by neurodevelopmental changes in the brain. However, the timing and nature of these changes have not been established. The aim of the present study was to determine whether three “classic” neurophysiological markers of schizophrenia are also characteristic of young adolescents (12-18 years) at ultra-high risk for psychosis (UHR).

Methods

63 young UHR individuals and 68 typically developing, age-, sex- and IQ-matched controls were recruited for neurophysiological assessment. Data for P50 suppression, prepulse inhibition (PPI) and smooth pursuit eye movements (SPEM) were gathered and compared.

Results

UHR individuals showed reduced PPI compared to controls, which became more pronounced when controls were directly compared to medication-naive UHR individuals (N = 39). There were no group differences in P50 or SPEM measures.

Conclusions

These results suggest that PPI is a relatively early vulnerability marker, while changes in other neurophysiological measures may only be detected or affected later during the illness course. Antipsychotic and antidepressant medication may aid in elevating PPI levels and potentially have a neuroprotective effect.     

Using structural MRI to identify individuals at genetic risk for bipolar disorders: a 2-cohort,machine learning study

Background

Brain imaging is of limited diagnostic use in psychiatry owing to clinical heterogeneity and low sensitivity/specificity of between-group neuroimaging differences. Machine learning (ML) may better translate neuroimaging to the level of individual participants. Studying unaffected offspring of parents with bipolar disorders (BD) decreases clinical heterogeneity and thus increases sensitivity for detection of biomarkers. The present study used ML to identify individuals at genetic high risk (HR) for BD based on brain structure.

Methods

We studied unaffected and affected relatives of BD probands recruited from 2 sites (Halifax, Canada, and Prague, Czech Republic). Each participant was individually matched by age and sex to controls without personal or family history of psychiatric disorders. We applied support vector machines (SVM) and Gaussian process classifiers (GPC) to structural MRI.

Results

We included 45 unaffected and 36 affected relatives of BD probands matched by age and sex on an individual basis to healthy controls. The SVM of white matter distinguished unaffected HR from control participants (accuracy = 68.9%, p = 0.001), with similar accuracy for the GPC (65.6%, p = 0.002) or when analyzing data from each site separately. Differentiation of the more clinically heterogeneous affected familiar group from healthy controls was less accurate (accuracy = 59.7%, p = 0.05). Machine learning applied to grey matter did not distinguish either the unaffected HR or affected familial groups from controls. The regions that most contributed to between-group discrimination included white matter of the inferior/middle frontal gyrus, inferior/middle temporal gyrus and precuneus.

Limitations

Although we recruited 126 participants, ML benefits from even larger samples.

Conclusions

Machine learning applied to white but not grey matter distinguished unaffected participants at high and low genetic risk for BD based on regions previously implicated in the pathophysiology of BD.     

Event-related potentials and changes of brain rhythm oscillations during working memory activation in patients with first-episode psychosis

Background

Earlier contributions have documented significant changes in sensory, attention-related endogenous event-related potential (ERP) components and θ band oscillatory responses during working memory activation in patients with schizophrenia. In patients with first-episode psychosis, such studies are still scarce and mostly focused on auditory sensory processing. The present study aimed to explore whether subtle deficits of cortical activation are present in these patients before the decline of working memory performance.

Methods

We assessed exogenous and endogenous ERPs and frontal θ event-related synchronization (ERS) in patients with first-episode psychosis and healthy controls who successfully performed an adapted 2-back working memory task, including 2 visual n-back working memory tasks as well as oddball detection and passive fixation tasks.

Results

We included 15 patients with first-episode psychosis and 18 controls in this study. Compared with controls, patients with first-episode psychosis displayed increased latencies of early visual ERPs and phasic θ ERS culmination peak in all conditions. However, they also showed a rapid recruitment of working memory–related neural generators, even in pure attention tasks, as indicated by the decreased N200 latency and increased amplitude of sustained θ ERS in detection compared with controls.

Limitations

Owing to the limited sample size, no distinction was made between patients with first-episode psychosis with positive and negative symptoms. Although we controlled for the global load of neuroleptics, medication effect cannot be totally ruled out.

Conclusion

The present findings support the concept of a blunted electroencephalographic response in patients with first-episode psychosis who recruit the maximum neural generators in simple attention conditions without being able to modulate their brain activation with increased complexity of working memory tasks.     

Structural brain correlates of sensorimotor gating in antipsychotic-naive men with first-episode schizophrenia

Background

Prepulse inhibition (PPI) of the startle reflex is modulated by a complex neural network. Prepulse inhibition impairments are found at all stages of schizophrenia. Previous magnetic resonance imaging (MRI) studies suggest that brain correlates of PPI differ between patients with schizophrenia and healthy controls; however, these studies included only patients with chronic illness and medicated patients. Our aim was to examine the structural brain correlates of PPI in antipsychotic-naive patients with first-episode schizophrenia.

Methods

We performed acoustic PPI assessment and structural MRI (1.5 and 3 T) in men with first-episode schizophrenia and age-matched controls. Voxel-based morphometry was used to investigate the association between PPI and grey matter volumes.

Results

We included 27 patients and 38 controls in the study. Patients had lower PPI than controls. The brain areas in which PPI and grey matter volume correlated did not differ between the groups. Independent of group, PPI was significantly and positively associated with regional grey matter volume in the right superior parietal cortex. Prepulse inhibition and grey matter volume associations were also observed in the left rostral dorsal premotor cortex, the right presupplementary motor area and the anterior medial superior frontal gyrus bilaterally. Follow-up analyses suggested that the rostral dorsal premotor cortex and presupplementary motor area correlations were driven predominantly by the controls.

Limitations

We used 2 different MRI scanners, which might have limited our ability to find subcortical associations since interscanner consistency is low for subcortical regions.

Conclusion

The superior parietal cortex seems to be involved in the regulation of PPI in controls and antipsychotic-naive men with first-episode schizophrenia. Our observation that PPI deficits in schizophrenia may be related to the rostral dorsal premotor cortex and presupplementary motor area, brain areas involved in maintaining relevant sensory information and voluntary inhibition, warrants further study.     

Aberrant Current Source-Density and Lagged Phase Synchronization of Neural Oscillations as Markers for Emerging Psychosis

Background:

Converging evidence indicates that neural oscillations coordinate activity across brain areas, a process which is seemingly perturbed in schizophrenia. In particular, beta (13-30 Hz) and gamma (30–50 Hz) oscillations were repeatedly found to be disturbed in schizophrenia and linked to clinical symptoms. However, it remains unknown whether abnormalities in current source density (CSD) and lagged phase synchronization of oscillations across distributed regions of the brain already occur in patients with an at-risk mental state (ARMS) for psychosis.

Methods:

To further elucidate this issue, we assessed resting-state EEG data of 63 ARMS patients and 29 healthy controls (HC). Twenty-three ARMS patients later made a transition to psychosis (ARMS-T) and 40 did not (ARMS-NT). CSD and lagged phase synchronization of neural oscillations across brain areas were assessed using eLORETA and their relationships to neurocognitive deficits and clinical symptoms were analyzed using linear mixed-effects models.

Results:

ARMS-T patients showed higher gamma activity in the medial prefrontal cortex compared to HC, which was associated with abstract reasoning abilities in ARMS-T. Furthermore, in ARMS-T patients lagged phase synchronization of beta oscillations decreased more over Euclidian distance compared to ARMS-NT and HC. Finally, this steep spatial decrease of phase synchronicity was most pronounced in ARMS-T patients with high positive and negative symptoms scores.

Conclusions:

These results indicate that patients who will later make the transition to psychosis are characterized by impairments in localized and synchronized neural oscillations providing new insights into the pathophysiological mechanisms of schizophrenic psychoses and may be used to improve the prediction of psychosis.Key words: schizophrenia, at-risk mental state (ARMS), resting state, EEG     

The Emotional Characteristics of Schizotypy

Objective

The aim of this study was to investigate the relationship between emotional traits and schizotypal symptoms and to establish a hypothetical model for the causal relationship between them.

Methods

Schizotypal symptoms were assessed using the Schizotypal Personality Questionnaire (SPQ), and a total of seven emotional traits considered to be potential risk factors for schizotypy were categorized as emotional disturbances, emotional attenuators or emotional amplifiers. A total of 502 undergraduate students completed the SPQ and other scales.

Results

The result of the present study suggested that the high levels of emotional disturbance in individuals who are prone to schizotypy or psychosis are amplified by their intensity and fluctuation. However, if their emotion attenuating abilities function well, these disturbances can be controlled and the schizotypal symptoms and progression to psychosis can be contained. Discriminant analysis showed that 69.0% of the subjects with many schizotypal symptoms and 80.7% of the subjects with few schizotypal symptoms were correctly classified.

Conclusion

The present study suggests the possibility of using emotional traits to identify the risk factors for psychosis.     

Stigma of Mental Illnesses as Perceived by North Korean Defectors Living in South Korea

Objective

This study aims to provide the information of the stigmas of mental illness such as psychosis, alcoholism, attempt suicide, and depression among North Korean defectors.

Methods

We examined stigma for the mental illnesses of 639 North Korean defectors aged 19 to 65 years who live in the Settlement Support Center for North Korean Refugees. The stigmas of mental illnesses were assessed using the Perceived Devaluation-Discrimination Scale We directly compared the stigma level between North Korean defectors and the general population of South Korea.

Results

North Korean defectors had higher perceived stigmas of psychosis and alcoholism and lower perceived stigmas of depression than South Koreans. Perceived stigma associated with attempted suicide was similar for North Korean defectors and South Koreans. Only marital status in sociodemographic variables had associations with higher perceived stigma of psychosis, alcoholism, and depression in the North Korean defectors. North Korean defectors, who spent more than one year in transit country, had associations with lower perceived stigma of psychosis and alcoholism. North Korean defectors, who had the experience of compulsory repatriation to North Korea or North Korean family in South Korea, had an association with higher perceived stigma of depression.

Conclusion

North Korean defectors had higher perceived stigmas of psychosis and alcoholism and lower perceived stigmas of depression than South Koreans. Further studies are needed to document serial changes in stigmas for mental illnesses associated with the receipt of education at the Settlement Support Center for North Korean defectors.     

Dexamphetamine selectively increases 40 Hz auditory steady state response power to target and nontarget stimuli in healthy humans

Background

An emerging endophenotype of schizophrenia is the reduction of both power and phase locking of the 40 Hz auditory steady state response (ASSR), and there have been a number of reports linking increased γ activity with positive psychotic symptoms. Schizophrenia and, more specifically, positive psychotic symptoms have been closely linked to increased dopamine (DA) neurophysiology. Therefore, we gave dexamphetamine to healthy participants to determine the effect that increased DA transmission would have on the ASSR.

Methods

We administered 0.45 mg/kg of dexamphetamine orally in a double-blind placebo-controlled crossover study. Stimuli were 20 Hz and 40 Hz click trains presented in an auditory oddball-type stimulus format (probability of stimulus presentation: 0.2 for targets, 0.8 for nontargets).

Results

We included 44 healthy volunteers (18 women) in the study. Dexamphetamine significantly increased the 40 Hz power for both target and nontarget ASSR stimuli. Dexamphetamine did not significantly affect the 40 Hz phase-locking factor (PLF) or the 20 Hz power and PLF. Whereas there were significant effects of selective attention on power and PLF for 20 and 40 Hz ASSR, there were no significant interactions between dexamphetamine and selective attention.

Limitations

Dexampheta-mine releases both noradrenaline and DA with equal potency. Further research with selective dopaminergic and noradrenergic agents will better characterize the effects of monoamines on γ activity.

Conclusion

The results demonstrate a frequency-specific effect of dexamphetamine on the ASSR. This finding is consistent with previous research that has found an association between increased γ and positive symptoms of psychosis. However, this result also raises the possibility that previous 40 Hz ASSR findings in people with schizophrenia may be confounded by effects of antipsychotic medication. Possible neural mechanisms by which dexamphetamine specifically increases 40 Hz power are also discussed.

Australian and New Zealand Clinical Trials Registry number

ACTRN12608000610336.     

A Disrupted-in-Schizophrenia 1 Gene Variant is Associated with Clinical Symptomatology in Patients with First-Episode Psychosis

Objective

DISC1 gene is one of the main candidate genes for schizophrenia since it has been associated to the illness in several populations. Moreover, variations in several DISC1 polymorphisms, and in particular Ser704Cys SNP, have been associated in schizophrenic patients to structural and functional modifications in two brain areas (pre-frontal cortex and hippocampus) that play a central role in the genesis of psychotic symptoms. This study tested the association between Ser704Cys DISC1 polymorphism and the clinical onset of psychosis.

Methods

Two hundred and thirteen Caucasian drug-naive patients experiencing a first episode of non-affective psychosis were genotyped for rs821616 (Ser704Cys) SNP of the DISC1 gene. The clinical severity of the illness was assessed using SAPS and SANS scales. Other clinical and socio-demographic variables were recorded to rule out possible confounding effects.

Results

Patients homozygous for the Ser allele of the Ser704Cys DISC1 SNP had significantly (p<0.05) higher rates at the positive symptoms dimension (SAPS-SANS scales) and hallucinations item, compared to Cys carriers.

Conclusion

DISC1 gene variations may modulate the clinical severity of the psychosis at the onset of the disorder.     

Electroencephalographic Abnormalities and 5-Year Outcome in First-Episode Psychosis

Objective:

To examine the relation of electroencephalographic abnormalities to 5-year outcomes in first-episode psychosis (FEP).

Methods:

Patients (n = 103) had their baseline electroencephalogram (EEG) classified by modified Mayo Clinic criteria. Symptoms and psychosocial functioning were rated after 5 years of treatment.

Results:

Dysrhythmic EEG was associated with persistence in positive and negative symptoms of psychoses and poorer psychosocial functioning at 5-year follow-up, independently of other characteristics, such as duration of untreated illness or premorbid adjustment. A higher percentage of people with comorbid substance use disorder had normal EEG.

Conclusions:

Abnormal baseline EEG in FEP is associated with poorer 5-year symptomatic and functional outcome.     

Association Between Symptom Dimensions and Categorical Diagnoses of Psychosis: A Cross-sectional and Longitudinal Investigation

Context:

Cross-sectional studies of the signs and symptoms of psychosis yield dimensional phenotypes. However, the validity and clinical utility of such dimensions remain debated. This study investigated the structure of psychotic symptomatology, the stability of the structure over time, and the concordance between symptom dimensions and categorical diagnoses.

Methods:

Sample consisted of 500 first-episode psychotic patients. A cross-sectional study (N = 500) investigated the organizational structure of symptom dimensions at the onset of psychosis and its concordance with categorical diagnoses; next, a nested longitudinal study (N = 100) examined the stability of the symptom dimensions structure after 5–10 years of follow-up.

Results:

Factor analyses identified 6 first-order factors (mania, negative, disorganization, depression, hallucinations, and delusions) and 2 high-order factors (affective and nonaffective psychoses). Cumulative variance accounted for by the first and high-order factors was 63%: 31% by the first-order factors and 32% by the high-order factors. The factorial structure of psychotic symptoms during first episode remained stable after 5–10 years of follow-up. The overall concordance between 4 categorical diagnostic groups (schizophrenia, mania with psychosis, psychotic depression and schizoaffective disorder) and dimensional symptom ranged from 62.2% to 73.1% (when the schizoaffective group was excluded).

Conclusions:

Symptoms of psychosis assume a multidimensional hierarchical structure. This hierarchical model was stable over time and showed good concordance with categorical diagnoses. The combined use of dimensional and categorical approach to psychotic disorders would be of clinical and research utility.Key words: symptom dimensions, diagnostic classification, psychosis, DSM-5, longitudinal study     

Neuropsychological and Behavioral Profiles in Attention-Deficit Hyperactivity Disorder Children of Parents with a History of Mood Disorders: A Pilot Study

Objective

We aimed to investigate the neurocognitive and behavioral endophenotypes of premorbid mood disorder. We compared intelligence, neuropsychological functioning, and behavioral problems among three groups: 1) a high-risk group [attention-deficit hyperactivity disorder (ADHD) children of parents with a history of a mood disorder], 2) a low-risk group (ADHD children of parents without a history of a mood disorder), and 3) normal comparison subjects.

Methods

We used the Korean Educational Development Institute Wechsler Intelligence Scale for Children-Revised (KEDI-WISC-R), the Stroop Color Word Interference Test (Stroop), the Wisconsin Card Sorting Test (WCST), and the Rey-Osterrieth Complex Figure Test (RCFT) as neurocognitive measures, and we used the Child Behavior Checklist (CBCL) as a behavioral measure. Performance on these neuropsychological tests and score on the CBCL of 18 high-risk children were compared to those of 20 low-risk children and 24 healthy children. We also assessed the children''s current mood state and familial functioning to control for the confounding effects of these variables.

Results

Compared to low-risk and healthy children, high-risk children were impaired on the Picture Completion and Stroop Word subtest and showed higher scores on the CBCL subscales representing internalizing symptoms. These significant group differences persisted even after adjustment for the children''s current mood state and familial functioning.

Conclusion

Neuropsychological deficits in the offspring of parents with a mood disorder may be associated with the current mood state rather than with innate characteristics, while their internalizing symptoms may partially stem from innate characteristics that are endophenotypes of a premorbid mood disorder.