The Shifting Subtypes of ADHD: Classification Depends on How Symptom Reports are Combined

Research on the correlates of ADHD subtypes has yielded inconsistent findings, perhaps because the procedures used to define subtypes vary across studies. We examined this possibility by investigating whether the ADHD subtype distribution in a community sample was sensitive to different methods for combining informant data. We conducted a study to screen all children in grades 1-5 (N = 7847) in a North Carolina County for ADHD. Teachers completed a DSM-IV behavior rating scale and parents completed a structured telephone interview. We found substantial differences in the distribution of ADHD subtypes depending on whether one or both sources were used to define the subtypes. When parent and teacher data were combined, the procedures used substantially influenced subtype distribution. We conclude the ADHD subtype distribution is sensitive to how symptom information is combined and that standardization of the subtyping process is required to advance our understanding of the correlates of different ADHD subtypes.     

Aquinas on Doctrine

Book reviewed:
Thomas Weinandy, Daniel Keating and John Yocum (eds). Aquinas on Doctrine: A Critical Introduction.     

Practical reasoning and practical knowledge

The judgement that provides the content of intention and coincides with the conclusion of practical reasoning is a normative judgement about what to do, and not, as Anscombe and McDowell argue, a factual judgement about what one is doing. Treating the conclusion of practical reasoning as expressing a recommendation rather than a verdict undermines McDowell’s argument; the special nature of practical reasoning does not preclude its conclusions being normative. Anscombe’s and McDowell’s claim that practical self-knowledge is productive of action may be accommodated by identifying the content of practical knowledge not with the conclusion but with a premise of practical reasoning – a kind of practical reasoning that occurs within rather than before action.     

The epidemiology of attention-deficit/hyperactivity disorder (ADHD): a public health view

Attention-deficit/hyperactivity disorder (ADHD) is the most common neurodevelopmental disorder of childhood. However, basic information about how the prevalence of ADHD varies by race/ethnicity, sex, age, and socio-economic status remains poorly described. One reason is that difficulties in the diagnosis of ADHD have translated into difficulties developing an adequate case definition for epidemiologic studies. Diagnosis depends heavily on parent and teacher reports; no laboratory tests reliably predict ADHD. Prevalence estimates of ADHD are sensitive to who is asked what, and how information is combined. Consequently, recent systematic reviews report ADHD prevalence estimates as wide as 2%-18%. The diagnosis of ADHD is complicated by the frequent occurrence of comorbid conditions such as learning disability, conduct disorder, and anxiety disorder. Symptoms of these conditions may also mimic ADHD. Nevertheless, we suggest that developing an adequate epidemiologic case definition based on current diagnostic criteria is possible and is a prerequisite for further developing the epidemiology of ADHD. The etiology of ADHD is not known but recent studies suggest both a strong genetic link as well as environmental factors such as history of preterm delivery and perhaps, maternal smoking during pregnancy. Children and teenagers with ADHD use health and mental health services more often than their peers and engage in more health threatening behaviors such as smoking, and alcohol and substance abuse. Better methods are needed for monitoring the prevalence and understanding the public health implications of ADHD. Stimulant medication is the treatment of choice for treating ADHD but psychosocial interventions may also be warranted if comordid disorders are present. The treatment of ADHD is controversial because of the high prevalence of medication treatment. Epidemiologic studies could clarify whether the patterns of ADHD diagnosis and treatment in community settings is appropriate. Population-based epidemiologic studies may shed important new light on how we understand ADHD, its natural history, its treatment and its consequences.     

Is Passive Syntax Semantically Constrained? Evidence From Adult Grammaticality Judgment and Comprehension Studies

To explain the phenomenon that certain English verbs resist passivization (e.g., *£5 was cost by the book), Pinker (1989) proposed a semantic constraint on the passive in the adult grammar: The greater the extent to which a verb denotes an action where a patient is affected or acted upon, the greater the extent to which it is compatible with the passive. However, a number of comprehension and production priming studies have cast doubt upon this claim, finding no difference between highly affecting agent‐patient/theme‐experiencer passives (e.g., Wendy was kicked/frightened by Bob) and non‐actional experiencer theme passives (e.g., Wendy was heard by Bob). The present study provides evidence that a semantic constraint is psychologically real, and is readily observed when more fine‐grained independent and dependent measures are used (i.e., participant ratings of verb semantics, graded grammaticality judgments, and reaction time in a forced‐choice picture‐matching comprehension task). We conclude that a semantic constraint on the passive must be incorporated into accounts of the adult grammar.     

A model of the neural mechanisms underlying multisensory integration in the superior colliculus

Much of the information about multisensory integration is derived from studies of the cat superior colliculus (SC), a midbrain structure involved in orientation behaviors. This integration is apparent in the enhanced responses of SC neurons to cross-modal stimuli, responses that exceed those to any of the modality-specific component stimuli. The simplest model of multisensory integration is one in which the SC neuron simply sums its various sensory inputs. However, a number of empirical findings reveal the inadequacy of such a model; for example, the finding that deactivation of cortico-collicular inputs eliminates the enhanced response to a cross-modal stimulus without eliminating responses to the modality-specific component stimuli. These and other empirical findings inform a computational model that accounts for all of the most fundamental aspects of SC multisensory integration. The model is presented in two forms: an algebraic form that conveys the essential insights, and a compartmental form that represents the neuronal computations in a more biologically realistic way.