Methylphenidate in hyperactive children: Differential effects of dose on academic,learning, and social behavior

Methylphenidate (Ritalin) has been shown to have differential effects on hyperactive children's behavior as a function of dose level. In the present investigation, a triple-blind, placebo-control, within-subject (crossover) experimental design was employed in which 12 hyperactive boys between 6 and 10 years received three different dosages of methylphenidate (5, 10, and 15 mg) in a randomly assigned sequence. Dosage effects were assessed on clinic(PAL-Paired Associates Learning test) and school-(percent on task, teacher ratings, work completion rates, and accuracy) related behaviors. For 10 of the children, classified as responders to medication by the PAL using the criteria of Swanson, Kinsbourne, and colleagues, a series of ANCOVAs with repeated measures showed significant dosage effects on teacher ratings (p 01), percent on task (p 01), academic accuracy (p 05), and assignment completion rates (p 05). PAL performance was also significantly enhanced (p 01) after optimal dose levels were considered. Subsequent trend analysis showed a significant positive linear relationship between dose and each of the dependent variables. A comparison of fixed-dose and miligram-per-kilogram plots showed that children's performance across the different dosages were clearly individualistic and task-specific, even when similar body weights were compared. The implications of using clinic-based testing to determine optimal medication responsivity were discussed.We would like to express our sincere appreciation to the following pediatricians for their valuable assistance: W. H. McDermott, D. J. Chronley, R. B. Trivett, F. J. Jehle, P. M. Small, and F. T. Leong. Grateful acknowledgement is also extended to the two anonymous reviewers whose comments contributed to the content of this paper, and to the undergraduate and graduate student members of the Children's Learning Clinic.     

Napping promotes inter-session habituation to emotional stimuli

The effects of a daytime nap on inter-session habituation to aversive visual stimuli were investigated. Healthy young adult volunteers viewed repeated presentations of highly negative and emotionally neutral (but equally arousing) International Affective Picture System (IAPS) photographs during two afternoon sessions separated by 2.5h. Half of the photographs were shown at both sessions (Repeated Sets) and half differed between sessions (Novel Sets). For each stimulus presentation, evoked skin conductance response (SCR), heart-rate deceleration (HRD) and corrugator supercilii EMG response (EMG), were computed and range corrected using respective maximum session-1 responses. Following each presentation, subjects rated each photograph on dimensions of pleasantness and arousability. During the inter-session interval, Nap subjects had a 120-min polysomnographically monitored sleep opportunity, whereas Wake subjects watched a non-stimulating video. Nap and Wake subjects did not differ in their subjective ratings of photographs. However, for Repeated-Set photographs, Nap subjects demonstrated greater inter-session habituation in SCR and EMG but a trend toward lesser inter-session habituation in HRD. These group differences were absent for Novel-Set photographs. Group differences across all measures were greater for negative stimuli. Occurrence of SWS during the nap was associated with greater inter-session habituation of EMG whereas occurrence of REM was associated with lesser inter-session habituation of SCR to negative stimuli. Sleep may therefore promote emotional adjustment at the level of somatic responses. Physiological but not subjective inter-session habituation to aversive images was enhanced by a daytime nap.     

Feigning combat-related posttraumatic stress disorder on the personality assessment inventory

This study examined whether individuals who were instructed on the Diagnostic and Statistical Manual of Mental Disorders (4th ed. [DSM-IV]; American Psychiatric Association, 1994) criteria for posttraumatic stress disorder (PTSD) could feign PTSD on the Personality Assessment Inventory (PAI; Morey, 1991). The study also investigated whether PAI indexes of symptom exaggeration, the Negative Impression Management (NIM) scale and the Malingering index, could identify individuals feigning PTSD. The diagnostic rule for PTSD (Morey, 1991, 1996) was applied to the profiles of a group of 23 veterans with combat-related PTSD and 23 male undergraduates instructed to malinger PTSD. Seventy percent of the student malingerers produced profiles that received diagnostic consideration for PTSD. The NIM cutting score (> or = 8) was highly effective in detecting simulation of PTSD but resulted in the misclassification of a large number of true PTSD cases. There were no significant differences in the overall efficiency of the test with various validity criteria. We discuss the implications of these findings for the use of the PAI in the diagnosis of combat-related PTSD.     

A daytime nap containing solely non-REM sleep enhances declarative but not procedural memory

The specialized role that sleep-specific brain physiology plays in memory processing is being rapidly clarified with a greater understanding of the dynamic, complex, and exquisitely orchestrated brain state that emerges during sleep. Behaviorally, the facilitative role of non-REM (NREM) sleep (primarily slow wave sleep) for declarative but not procedural memory performance in humans has been demonstrated in a number of nocturnal sleep studies. However, subjects in these studies were tested after periods of sleep that contained REM sleep in addition to NREM sleep, and comparison wake groups were subjected to mild sleep deprivation. To add some clarity to the findings of these nocturnal studies, we assessed performance on declarative and procedural memory tasks following a daytime training-retest interval containing either a short nap that included NREM without REM sleep, or wakefulness. Consistent with previous findings we show that, after a comparatively brief sleep episode, subjects that take a nap improve more on a declarative memory task than subjects that stay awake, but that improvement on a procedural memory task is the same regardless of whether subjects take a nap or remain awake. Slow wave sleep was the only sleep parameter to correlate positively with declarative memory improvement. These findings are discussed with reference to the general benefits of napping and within the broader context of a growing literature suggesting a role for NREM-specific physiology for the processing of declarative memory.     

An Assessment of Risk Understanding in Hispanic Genetic Counseling Patients

This study sought to identify if differences existed in risk comprehension and risk format understanding between genetic counseling patients of Hispanic and Caucasian ethnicity. A total of 107 questionnaires were collected, 56 from Hispanic patients, and 51 from Caucasian controls. Of the total population 41.1% (44/107) could not demonstrate sufficient risk understanding, which was 71.4% (40/56) of Hispanics and 7.8% (4/51) of Caucasians. Fractions were the best-understood format for all participants. However, both Hispanics and Caucasians had difficulties with the percentage risk format. Discrepancies were also noted in qualitative word format understanding. Awareness of differences in risk comprehension may affect the selection of counseling techniques and strategies utilized by genetic counselors when educating patients about risk related information.     

Frontolimbic response to negative feedback in clinical depression

Functional neuroimaging suggests that limbic regions of the medial frontal cortex may be abnormally active in individuals with depression. These regions, including the anterior cingulate cortex, are engaged in both action regulation, such as monitoring errors and conflict, and affect regulation, such as responding to pain. The authors examined whether clinically depressed subjects would show abnormal sensitivity of frontolimbic networks as they evaluated negative feedback. Depressed subjects and matched control subjects performed a video game in the laboratory as a 256-channel EEG was recorded. Speed of performance on each trial was graded with a feedback signal of A, C, or F. By 350 ms after the feedback signal, depressed subjects showed a larger medial frontal negativity for all feedback compared with control subjects with a particularly striking response to the F grade. This response was strongest for moderately depressed subjects and was attenuated for subjects who were more severely depressed. Localization analyses suggested that negative feedback engaged sources in the anterior cingulate and insular cortices. These results suggest that moderate depression may sensitize limbic networks to respond strongly to aversive events.     

Ambivalence Over Emotional Expression and Psychological Weil-Being Among Rheumatoid Arthritis Patients and Their Spouses1

Associations between ambivalence over emotional expression and psychological well-being among rheumatoid arthritis patients and their spouses were investigated. Sixty-nine couples completed questionnaires assessing ambivalence over emotional expression, emotional expressiveness, psychological well-being, and strategies used in coping with arthritis. Associations between the patient's ambivalence and psychological well-being were stronger for those married to a highly ambivalent spouse, although this pattern of results was not found for spouses. Lower psychological well-being among more ambivalent spouses, and to a lesser extent patients, could be partially explained by their greater use of passive and distancing coping strategies. Results emphasize the importance of taking a dyadic approach to the study of psychological functioning among chronically ill patients and their spouses.     

Age-related changes in the associations of social network ties with mortality risk

Age-related changes in the associations of social network ties with mortality risk were investigated using data from the Terman Life-Cycle Study (L. M. Terman, 1925; L. M. Terman & M. H. Oden, 1947, 1959). Marital status, number of living children, number of living siblings, and number of group memberships in 1940, 1950, 1960, and 1977 were reported across middle adulthood by 697 men and 544 women, with mortality follow-up as of 1991. Initial analyses confirmed previous work indicating that marital history (men only), number of children (both genders), and organizational memberships (both genders) are predictive of mortality risk. Further analyses compared the associations between these social ties and mortality prior to age 70 and at age 70 and older. Results indicated that for men, experiencing marital dissolution and subsequently remarrying is a stronger predictor of mortality risk prior to age 70 (p = .05), whereas for women, number of children (p < .05) is a stronger predictor of mortality risk after age 70. Implications of these age-related changes in social ties and mortality risk are discussed.