Neurophysiological correlates of excitement in men with recent-onset psychosis

OBJECTIVE

Right frontal function, as indicated by the N200 component of the event-related potential during target detection, has previously been associated with excitement (excitement, impulsivity, hostility, uncooperativeness) in men with a long-term diagnosis of schizophrenia. The current study investigated excitement in relation to N200 in men who had recently experienced their first episode of psychosis.

SUBJECTS AND METHODS

Twenty men who had recently suffered their first psychotic episode underwent a clinical interview and auditory oddball task.

RESULTS

Multiple linear regression analysis showed that 58% of the variance in the excitement symptom cluster was explained by a positive association with frontal midline N200 amplitude and an inverse association with right frontal N200 amplitude. The latter was not apparent in the initial correlation, suggesting suppression by the midline activity. These associations were not explained by drug use, medication or negative symptoms. However, the correlation between excitement and midline N200 was stronger in drug users, and that between right frontal N200 and excitement was stronger in nonusers.

CONCLUSION

Findings support the independent contributions to excitement of mechanisms reflected in midline and right frontal N200 amplitude respectively during the early stages of psychosis.

Sleep-wake cycle phenotypes in young people with familial and non-familial mood disorders

OBJECTIVES

Converging evidence identifies that the offspring of parents with bipolar disorder (BD), individuals at clinical high risk of BD, and young people with recent onset BD may differ from other clinical cases or healthy controls in terms of sleep-wake profiles. However, it is possible that these differences may reflect current mental state, subtype of mood disorder, or familial traits. This study aimed to determine objective and subjective sleep-wake profiles in individuals aged 15-25 years with a current major depressive episode, in relation to familial traits.

METHODS

Frequency matching was employed to ensure that each individual with a confirmed family history of BD (FH+) could be compared to four controls who did not have a familial mood disorder (FH-). Pre-selected objective actigraphy and subjective Pittsburgh Sleep Quality Index (PSQI) ratings were compared using one-way analysis of variance (ANOVA) and applying the Benjamini-Hochberg (BH) correction for false discoveries.

RESULTS

The sample comprised 60 individuals with a mean age of 19 years. The FH+ (n=12) and FH- groups (n=48) differed on three key sleep parameters: mean sleep duration on week nights (P=.049), variability in waking after sleep onset (P=.038), and daily disturbances (PSQI dimension of sleep disturbance and daytime dysfunction; P=.01).

CONCLUSIONS

The sleep profiles we identified in this study, especially the daily disturbances phenotype, provide support for research into endophenotypes for BD. Also, the findings may offer the opportunity for more tailored, personalized interventions that target specific components of the sleep-wake cycle in individuals with a family history of BD.

Transitions Study of predictors of illness progression in young people with mental ill health: study methodology

AIM

An estimated 75% of mental disorders begin before the age of 24 and approximately 25% of 13-24-year-olds are affected by mental disorders at any one time. To better understand and ideally prevent the onset of post-pubertal mental disorders, a clinical staging model has been proposed that provides a longitudinal perspective of illness development. This heuristic model takes account of the differential effects of both genetic and environmental risk factors, as well as markers relevant to the stage of illness, course or prognosis. The aim of the Transitions Study is to test empirically the assumptions that underpin the clinical staging model. Additionally, it will permit investigation of a range of psychological, social and genetic markers in terms of their capacity to define current clinical stage or predict transition from less severe or enduring to more severe and persistent stages of mental disorder.

METHOD

This paper describes the study methodology, which involves a longitudinal cohort design implemented within four headspace youth mental health services in Australia. Participants are young people aged 12-25 years who have sought help at headspace and consented to complete a comprehensive assessment of clinical state and psychosocial risk factors. A total of 802 young people (66% female) completed baseline assessments. Annual follow-up assessments have commenced.

CONCLUSIONS

The results of this study may have implications for the way mental disorders are diagnosed and treated, and progress our understanding of the pathophysiologies of complex mental disorders by identifying genetic or psychosocial markers of illness stage or progression.

Neurophysiological markers of contextual processing: the relationship between P3b and Gamma synchrony and their modulation by arousal, performance and individual differences

The ability to identify and respond to significant events in the environment is a vital aspect of human cognition and yet is poorly understood as a dynamic neural process. While the response to a contextually-relevant stimulus involves a number of complimentary processes, including selective attention and neural binding, it is also subject to modulation by factors like arousal, age and sex. Adopting an integrative approach, we investigated contextual processing (as indexed by P3b and Gamma phase synchrony) in 120 healthy subjects performing an auditory oddball task while controlling for these other modulating factors. Results suggest a relationship between P3b and Gamma-2 synchrony in posterior regions only, with phasic anterior processing seemingly unrelated to that in posterior regions. However, only the P3b was significantly correlated to central and autonomic arousal. Further, while age and sex were associated with variation in individual measures, they did not strongly affect the relationship between the measures. We concluded that, in simple contextual processing, global and local elements of target stimuli are processed in parallel with little variation being shown between the sexes or resulting from increasing age.

The dose-dependent effect of methylphenidate on performance, cognition and psychophysiology

The effects of methylphenidate (MPH) on 32 healthy human male volunteers (aged 18 to 25 years, mean age=22.26) were examined using a within-subject design. Each participant attended six testing periods, held once per week. Within each testing period, three repeat testing sessions were undertaken: pre-medication, on-medication and two hours post-medication. In these sessions, dose was manipulated (placebo, 5 mg, 15 mg or 45 mg) according a double-blind placebo design. In this report, we focus on behavioral, autonomic arousal (heart rate, skin conductance) and psychophysiological (ERP) data acquired during the working memory task. We found increased autonomic arousal (heart rate, skin conductance and blood pressure) with MPH. A linear reduction in reaction time, omission errors and target P3 latency, and a corresponding increase in background P3 amplitude was observed with increased MPH dose. The relationship between these measures supported an increase in performance and underlying brain function with MPH. To our knowledge, this is the first paper to use behavioral, arousal and electrophysiological measures in an integrative approach to study the effects of MPH on healthy adults.

Integrative neuroscience: the role of a standardized database

Most brain related databases bring together specialized information, with a growing number that include neuroimaging measures. This article outlines the potential use and insights from the first entirely standardized and centralized database, which integrates information from neuroimaging measures (EEG, event related potential (ERP), structural/functional MRI), arousal (skin conductance responses (SCR)s, heart rate, respiration), neuropsychological and personality tests, genomics and demographics: The Brain Resource International Database. It comprises data from over 2000 "normative" subjects and a growing number of patients with neurological and psychiatric illnesses, acquired from over 50 laboratories (in the U.S.A, United Kingdom, Holland, South Africa, Israel and Australia), all with identical equipment and experimental procedures. Three primary goals of this database are to quantify individual differences in normative brain function, to compare an individual's performance to their database peers, and to provide a robust normative framework for clinical assessment and treatment prediction. We present three example demonstrations in relation to these goals. First, we show how consistent age differences may be quantified when large subject numbers are available, using EEG and ERP data from nearly 2000 stringently screened. normative subjects. Second, the use of a normalization technique provides a means to compare clinical subjects (50 ADHD subjects in this study) to the normative database with the effects of age and gender taken into account. Third, we show how a profile of EEG/ERP and autonomic measures potentially provides a means to predict treatment response in ADHD subjects. The example data consists of EEG under eyes open and eyes closed and ERP data for auditory oddball, working memory and Go-NoGo paradigms. Autonomic measures of skin conductance (tonic skin conductance level, SCL, and phasic skin conductance responses, SCRs) were acquired simultaneously with central EEG/ERP measures. The findings show that the power of large samples, tested using standardized protocols, allows for the quantification of individual differences that can subsequently be used to control such variation and to enhance the sensitivity and specificity of comparisons between normative and clinical groups. In terms of broader significance, the combination of size and multidimensional measures tapping the brain's core cognitive competencies, may provide a normative and evidence-based framework for individually-based assessments in "Personalized Medicine."

Spontaneous alpha peak frequency predicts working memory performance across the age span

Working memory capacity has been consistently shown to decline with increasing age. Mechanisms underlying this decline are poorly understood. One index that has been found to predict performance on memory tests is alpha peak frequency, the peak of spectral alpha power of the EEG. Activity in the alpha band has been also associated with higher cognitive functions including attention and anticipation and has been shown to slow with age. Few studies, however, have examined whether there might be a relationship between WM decline and alpha peak frequency. The present study specifically investigated this relationship. Digit span was used as the index of WM function. The study made use of 550 normal subjects aged between 11 and 70 years in the Brain Resource International Database. The data were acquired from six laboratories located in the USA (2), Europe (2) and Australia (2). Forward and reverse digit span were found to be lower in older relative to younger age groups. Spontaneous alpha peak frequency slowed with age and more so at anterior than posterior sites. Frontal alpha peak frequency was found to be a significant predictor of reverse digit span, with each 1 Hz increase in frequency associated with a 0.21 increase in reverse digit span score and this was independent of age, indicating a positive relationship between alpha peak frequency and working memory performance.

Exacerbation of chronic ulcerative colitis with mesalamine

Activation of ulcerative colitis with mesalamine has rarely been reported. In case 1, a 34-year-old man was treated with oral mesalamine, resulting in an exacerbation of colitis that rapidly improved with glucocorticoids and mesalamine withdrawal. Oral cromolyn sodium and occasional low-dose prednisone therapy has maintained long-term remission. In case 2, a 28-year-old man receiving prednisone treatment developed chest pain and myalgias 1 week after initiation of mesalamine that resolved on mesalamine withdrawal. A lower dose of mesalamine with continued glucocorticoids resulted in clinical improvement, and both drugs were tapered. Mesalamine sensitivity was documented endoscopically and histologically by evaluating mucosal changes after two mesalamine enemas during a 24-hour period. There was dramatic progression from quiescent disease to active colitis in 24 hours. Mesalamine sensitivity must be included in the differential diagnosis of ulcerative colitis exacerbations. Concurrent steroid therapy can suppress systemic side effects, making the diagnosis even more elusive.