Placebo effects in developmental disabilities: implications for research and practice

Recent clinical trials of secretin in children with autism showed robust placebo effects and no benefit of secretin over placebo. This article explores the reasons for the observed placebo effects, focusing on the heightening of positive expectancy by media attention and by the sensory experiences associated with intravenous injections. Comparisons are drawn with research involving other novel treatments and other clinical populations of children with developmental disabilities and neurobehavioral disorders. Research regarding mechanisms of placebo effects is reviewed, including patient and clinician attributes, expectancy effects, participation effects, changes in caregiver behavior, and conditioning. New evidence regarding the biological basis of placebo effects is briefly presented. Since placebo effects are ubiquitous and may operate by a variety of mechanisms, research design is critical in designing clinical trials and in evaluating other outcomes research. Measurement issues important for research in developmental disabilities are emphasized. Ethical concerns have been raised regarding the use of placebo in clinical research, but current analysis suggests that placebo controls are necessary and defensible on ethical grounds, if certain conditions are met. The study of placebo effects ("placebology") holds great promise as a new area of research in therapeutics. The author's research in the potential augmentation of stimulant effects in children with attention deficit/hyperactivity disorder (ADHD) by adding placebo in open label is briefly presented. The placebo has always been integral to the practice of medicine, but advances in scientific medicine and medical ethics have diminished the role and use of placebo in practice. An innovative approach to the ethical use of placebo is proposed.     

Testosterone and Proactive-Reactive Aggression in Youth: the Moderating Role of Harsh Discipline

This study tests a biosocial model of the link between testosterone and proactive-reactive aggression in youth at varying levels of harsh discipline. Given that proactive aggression is used to gain power and status and the importance of social learning in its formation, we hypothesized that testosterone would be associated with proactive aggression at higher levels of harsh discipline, and that this relationship would be more pronounced in boys than girls. Participants (n?=?445; 50% male; M age?=?11.92 years; 80% African-American) and their caregivers completed questionnaires including demographics, conflict tactics, and proactive-reactive aggression. Youth also provided a saliva sample for testosterone. Analyses revealed an interaction between testosterone and harsh discipline on proactive aggression in both boys and girls, and an interaction between testosterone and harsh discipline on reactive aggression in boys only. For those experiencing high levels of harsh discipline, testosterone was positively associated with proactive aggression, with the magnitude of the association increasing as harsh discipline increased. For below average levels of harsh discipline, there were protective effects of high testosterone for boy’s reactive aggression and for girl’s proactive aggression. The findings support basic tenets of the biosocial model which suggest that links between testosterone and aggressive behavior are dependent on contextual forces, highlighting the complex relationship between hormones, social context, and aggression. Novel findings include protective effects of high testosterone for those exposed to low levels of harsh discipline. Findings are discussed in light of the context-contingency effect and also within the differential susceptibility framework.     

The effects of body mass index and waist-to-hip ratio on ratings of female attractiveness, fecundity, and health

This paper examines the effects of body mass index (BMI) and waist-to-hip ratio (WHR) on people’s perceptions of female attractiveness and fecundity. One hundred and two participants (51 females) were asked to rate 18 line drawings, varying across three BMI and six WHR levels, on seven different attributes (‘healthy’, ‘fertile’, ‘youthful’, ‘intelligent’, ‘nurturing’, ‘flirty’, and ‘attractive’). Line drawings manipulated arm and leg thickness while keeping torso WHR consistent, thus unconfounding previously confounded variables. The data were analysed through a doubly multivariate analysis of variance. Effect sizes were larger for BMI than for WHR. Figures of average weight and a WHR of 0.7 were rated as most attractive and healthy. Overall, the results demonstrate that the effects of BMI and WHR on perceptions of attractiveness and fecundity are interdependent and should be studied concurrently rather than in isolation.     

The Effect of Pedestrian Clothing in 18,000 Road-Crossing Episodes

A confederate dressed in either smart or unkempt clothing made 18,000 attempts to cross the road at legally designated crossing points. Consistent with their statutory obligation, drivers were more likely to stop than not stop for the confederate, irrespective of the latter's clothing. However, the findings reflected those of previous studies showing that drivers were more likely to stop when the confederate was dressed smartly.     

Processing speed mediates the development of general intelligence (g) in adolescence

In the research reported here, we examined whether processing speed mediates the development of general intelligence (g) in adolescence. Using the Armed Services Vocational Aptitude Battery, a battery of 12 diverse cognitive tests, we assessed processing speed and g in a large sample of 13- to 17-year-olds obtained from the National Longitudinal Survey of Youth (N = 6,969). The direct effect of age on g was small compared with the total effect of age on g, which was almost fully mediated through speed. The results suggest that increases in g in adolescence can be attributed to increases in mental speed.     

The neural basis of event-time introspection

We explored the neural mechanisms allowing humans to report the subjective onset times of conscious events. Magnetoencephalographic recordings of neural oscillations were obtained while human subjects introspected the timing of sensory, intentional, and motor events during a forced choice task. Brain activity was reconstructed with high spatio-temporal resolution. Event-time introspection was associated with specific neural activity at the time of subjective event onset which was spatially distinct from activity induced by the event itself. Different brain regions were selectively recruited for introspection of different event types, e.g., the bilateral angular gyrus for introspection of intention. Our results suggest that event-time introspection engages specific neural networks to assess the contents of consciousness. Subjective event times should therefore be interpreted as the result of complex interactions between introspection and experience networks, rather than as direct reproduction of the individual’s conscious state or as a mere post hoc interpretation.     

Brain abnormalities in antisocial individuals: implications for the law

With the increasing popularity in the use of brain imaging on antisocial individuals, an increasing number of brain imaging studies have revealed structural and functional impairments in antisocial, psychopathic, and violent individuals. This review summarizes key findings from brain imaging studies on antisocial/aggressive behavior. Key regions commonly found to be impaired in antisocial populations include the prefrontal cortex (particularly orbitofrontal and dorsolateral prefrontal cortex), superior temporal gyrus, amygdala-hippocampal complex, and anterior cingulate cortex. Key functions of these regions are reviewed to provide a better understanding on how deficits in these regions may predispose to antisocial behavior. Objections to the use of imaging findings in a legal context are outlined, and alternative perspectives raised. It is argued that brain dysfunction is a risk factor for antisocial behavior and that it is likely that imaging will play an increasing (albeit limited) role in legal decision-making.     

Lonelier, lazier, and teased: the stigmatizing effect of body size

The authors conducted 2 studies to examine the stigmatization of the female and male body using photographic stimuli of real people. In the first study, 75 female and 55 male undergraduates rated a series of 50 photographs of women ranging in body mass index (BMI) on 3 items: gets teased, lonely, and lazy. Both male and female observers rated bodies on either side of BMI 19-20 kg/m2 higher for the gets teased and lonely items. For the lazy item, there was a clear pattern of greater stigmatization with increasing BMI. In the second study, 40 male and 40 female observers rated a series of photographs of the male body that varied in BMI and waist-to-chest ratio on the same items. Results showed that men and women judged overweight and more tubular men to be lazier, lonelier, and teased. These findings suggest that body size is an important characteristic to consider when examining body stigmatization among men and women. These results also show support for the beautiful-is-good bias.