Pathways from Birth Weight to ADHD Symptoms through Fluid Reasoning in Youth with or without Intellectual Disability

Although individual differences in fluid reasoning reliably mediate predictions of attention-deficit/hyperactivity disorder (ADHD) symptoms from birth weight in youth with typical cognitive development (TD), it is unknown if this indirect effect operates similarly in the development of ADHD symptoms secondary to intellectual disability (ID). Thus, we evaluated mediation by fluid reasoning in a longitudinal sample of 163 youth (45% female) with (n = 52) or without (n = 111) ID who were followed prospectively from age 5 to age 13. At age 9, youth completed the Arithmetic subtest of the Wechsler Intelligence Scale for Children, a measure of fluid reasoning. At ages 9 and 13, mothers and teachers separately rated youth ADHD symptoms and mothers completed a diagnostic interview. Mediation was tested via path analysis with bootstrapped confidence intervals, and moderated mediation estimated whether indirect effects differed between ID and TD youth or based on youth IQ. Controlling for demographic factors and age 9 ADHD symptoms, age 9 Arithmetic mediated birth weight and multi-method/informant age 13 ADHD symptoms, such that birth weight positively predicted Arithmetic, which negatively predicted ADHD symptoms. Neither ID status nor IQ moderated the observed indirect effect through Arithmetic, suggesting that it was similar for ID and TD youth as well as across the range of youth IQs. These findings support previous evidence that fluid reasoning, as measured by Arithmetic, may causally mediate birth weight and ADHD symptoms, and suggest that this pathway operates similarly with respect to the development of ADHD symptoms in youth with ID.     

Development and validation of a brief self-report measure of trauma exposure: the Trauma History Screen

Although information about individuals' exposure to highly stressful events such as traumatic stressors is often very useful for clinicians and researchers, available measures are too long and complex for use in many settings. The Trauma History Screen (THS) was developed to provide a very brief and easy-to-complete self-report measure of exposure to high magnitude stressor (HMS) events and of events associated with significant and persisting posttraumatic distress (PPD). The measure assesses the frequency of HMS and PPD events, and it provides detailed information about PPD events. Test-retest reliability was studied in four samples, and temporal stability was good to excellent for items and trauma types and excellent for overall HMS and PPD scores. Comprehensibility of items was supported by expert ratings of how well items appeared to be understood by participants with relatively low reading levels. In five samples, construct validity was supported by findings of strong convergent validity with a longer measure of trauma exposure and by correlations of HMS and PPD scores with posttraumatic stress disorder (PTSD) symptoms. The psychometric properties of the THS appear to be comparable or better than longer and more complex measures of trauma exposure.     

Duties to Companion Animals

This paper outlines the moral contours of human relationships with companion animals. The paper details three sources of duties to and regarding companion animals: (1) from the animal’s status as property, (2) from the animal’s position in relationships of care, love, and dependency, and (3) from the animal’s status as a sentient being with a good of its own. These three sources of duties supplement one another and not only differentiate relationships with companion animals from wild animals and other categories of domestic animals such as livestock, but they also overlap to provide moral agents with additional reasons for preventing and avoiding harm to companion animals. The paper concludes that not only do owners and bystanders have direct and indirect duties to protect companion animals from harm, but also that these duties have the potential, in some circumstances, to clash with duties owed to the state and fellow citizens.     

Posterior cingulate cortex: adapting behavior to a changing world

When has the world changed enough to warrant a new approach? The answer depends on current needs, behavioral flexibility and prior knowledge about the environment. Formal approaches solve the problem by integrating the recent history of rewards, errors, uncertainty and context via Bayesian inference to detect changes in the world and alter behavioral policy. Neuronal activity in posterior cingulate cortex - a key node in the default network - is known to vary with learning, memory, reward and task engagement. We propose that these modulations reflect the underlying process of change detection and motivate subsequent shifts in behavior.