Neurobiological Markers of Illness Onset in Psychosis and Schizophrenia: The Search for a Moving Target

In this review, we describe neuropsychological and brain imaging findings in the early stages of psychosis and schizophrenia. We focus on recent clinical high-risk studies and consider whether the evidence supports these as ‘endophenotypes’ of a vulnerability to the illness or as ‘biomarkers’ of illness onset and transition. The findings suggest that there are a number of processes at psychosis onset that may represent biomarkers of incipient illness. These neurobiological indices particularly implicate the integrity of frontal and temporal cortices, which may or may not be related to the genetics of psychosis (i.e. potential ‘endophenotypes’). However, these brain regions are dynamically changing during normal maturation, meaning that any putative neurobiological markers identified at the earliest stages of illness may be relatively unstable. We suggest that, while such measures may be readily identified as potential neurobiological markers of established illness, they are inconsistent at (or around) the time of illness onset when assessed cross-sectionally. Instead, identification of more valid risk markers may require longitudinal assessment to ascertain normal or abnormal trajectories of neurodevelopment. Accordingly, we assert that the current conceptualisations of potential biomarkers and/or ‘endophenotypes’ for schizophrenia may need to be reconsidered in the context of normal and abnormal brain maturational processes at the time of onset of psychotic disorders.     

Diversion of attention in everyday concept learning: Identification in the service of use

Many people tend to believe that natural categories have perfectly predictive defining features. They do not easily accept the family resemblance view that the features characteristic of a category are not individually sufficient to predict the category. However, common category-learning tasks do not produce this simpler-than-it-is belief. If there is no simple classification principle in a task, the participants know that fact and can report it. We argue that most category-learning tasks in which family resemblance categories are used fail to produce the everyday simpler-than-it-is belief because they encourage analysis of identification criteria during training. To simulate the learning occurring in many natural circumstances, we developed a procedure in which participants' analytic activity is diverted from the way in which the stimuli are identified to the use to which the stimuli will be put. Finally, we discuss the prevalence of this diverted analysis in everyday categorization.     

Do Colours Look Like Dispositions? Reply to Langsam and Others

Dispositional theories of colour have been attacked by McGinn and others on the ground that 'Colours do not look like dispositions'. Langsam has argued that on the contrary they do, in 'Why Colours Do Look Like Dispositions', The Philosophical Quarterly , 50 (2000), pp. 68–75. I make three claims. First, neither side has made its case. Secondly, it is true, at least on one interpretation, that colours do not look like dispositions. Thirdly, this does not show that dispositionalism about colours is false.     

The role of personality in exposure and reactivity to interpersonal stress in relation to arthritis disease activity and negative affect in women.

The role of personality in the stress process was examined in older women with rheumatoid arthritis (RA) and osteoarthritis (OA) and in healthy controls (HCs). Reactivity was examined in relation to arthritis disease activity and negative affect. Interpersonal sensitivity and neuroticism were measured in questionnaires, and interpersonal stress, negative affect, and disease activity were assessed weekly for 12 weeks. Interpersonal sensitivity was defined as an excessive sensitivity to the behavior and feelings of others. Regarding exposure, neuroticism was related to interpersonal stress for all groups. Regarding reactivity, interpersonal sensitivity interacted with interpersonal stress to predicted elevations in negative affect in all groups and elevations in disease activity in the arthritis groups. There were no significant differences in the effects.     

Evaluation of meditation and relaxation on physiological response during the performance of fine motor and gross motor tasks

This study investigated the effects of meditation/relaxation on physiological responses during the performance of a fine motor and a gross motor task. A pretest-posttest control group, randomized-blocks design was used to study a group of 16 meditators and a group of 16 nonmeditators, subgroups of each who relaxed prior to performing on a pursuit-rotor tracking device as a fine motor task and to performing the Luft cycle ergometer protocol to a heart rate of 70% of age-adjusted maximum heart rate as a gross motor task. During each of these tasks heart rate, systolic blood pressure, rate-pressure-product, and EMG activity of the frontalis muscle were monitored. No significant difference in the performance of either the fine motor or the gross motor task was noted for persons practicing meditation and persons who were nonmeditators but were given the opportunity to relax prior to a motor task. Likewise, no significant difference was noted in the pattern of response to the imposed fine motor or gross motor task by meditators or relaxed nonmeditators.     

Factors associated with Borderline pathology in school-age children

The Diagnostic Interview for Borderlines as revised (DIB-R) for use with children and chart review was completed using the records of 54 children, ages 6 to 12 years, who had been admitted to a public psychiatric hospital. Based on the results of the DIB-R, the children were grouped as borderline and nonborderline. The two groups were then compared with regard to 52 independent variables which have historically been associated with the borderline diagnosis. Stepwise logistic regression was used to identify the cluster of diagnostic and independent variables which best discriminated the borderline subjects. Self-destructive behavior, irritable affect, anhedonia, and an externalizing disorder diagnosis at the time of admission accounted for 95.4% of the borderline children. These findings are in contrast to previous studies which have found an assortment of neuropsychological and/or neurological deficits and stressed the importance of a tendency toward psychotic regression on psychological testing as discriminative variables. The authors underscore the idea that borderline pathology may represent a spectrum of disorders and the need for a more specific psychiatric nosology in describing and diagnosing these children.     

Effects of graded doses of alcohol on speed-accuracy tradeoff in choice reaction time

The inconsistency of previous results concerning the effects of alcohol on reaction time (RT) may be related to possible tradeoffs between speed and accuracy. In the present experiment, complete speed-accuracy tradeoff functions were generated for each of five doses of alcohol (0-1.33 ml/kg) in a choice RT task. Such functions permit RT differences resulting from changes in performance efficiency to be distinguished from those due to changes in subjects’ speed accuracy criteria. Increasing doses of alcohol produced a progressive decrease in the slope parameter of linear equations fit to the speed-accuracy data, but did not significantly alter the intercept of the functions with the RT axis. Thus, alcohol reduced performance efficiency by decreasing the rate of growth of accuracy per unit time. A change in speed-accuracy criterion was combined with the decrease in efficiency at the highest alcohol dose.