[Show abstract][Hide abstract] ABSTRACT: Pediatric bipolar disorder is a severe and impairing illness. Characterizing the impact of pediatric bipolar disorder on cognitive function might aid in understanding the phenomenology of the disorder. While previous studies of pediatric bipolar disorder have reported deficits in cognitive control and reward behavior, little is understood about how affective processes influence behavioral control. Relative to prior studies using manual-response paradigms, eye movement tasks provide a more precise assessment of reward sensitivity and cognitive and motor control. The current study compares 20 youths with bipolar disorder (mean age = 13.9 years ± 2.22) and 23 healthy subjects (mean age = 13.8 years ± 2.49) on a mixed pro-antisaccade task with monetary incentives. On both types of saccades, participants were presented with three types of incentives: those where subjects can win money, lose money, or neither win nor lose money. Impaired reward processing was found in youths with bipolar disorder relative to controls, particularly on antisaccades. This difference was reflected in lower error rates during incentive trials in the control but not in the bipolar disorder group. By comparison, no group differences were found on prosaccade trials. The results provide further evidence for deficits in cognitive and reward processing in bipolar disorder.
Journal of Psychopharmacology 12/2010; 24(12):1779-84. DOI:10.1177/0269881109353462 · 3.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This 4-year longitudinal study examined whether performance on a decision-making task and an emotion-processing task predicted the initiation of tobacco, marijuana, or alcohol use among 77 adolescents. Of the participants, 64% met criteria for an externalizing behavioral disorder; 33% did not initiate substance use; 13% used one of the three substances under investigation, 18% used two, and 36% used all three. Initiation of substance use was associated with enhanced recognition of angry emotion, but not with risky decision-making. In conclusion, adolescents who initiate drug use present vulnerability in the form of bias towards negative emotion but not toward decisions that involve risk.
[Show abstract][Hide abstract] ABSTRACT: Previous theories implicate hippocampal dysfunction in anxiety disorders. Most of the data supporting these theories stem from animal research, particularly lesion studies. The generalization of findings from rodent models to human function is hampered by fundamental inter-species differences. The present work uses a task of spatial orientation, which is known to rely on hippocampal function. Deficits in spatial navigation in anxious children suggest that the hippocampal network involved in spatial orientation is also implicated in anxiety disorders.
Thirty-four treatment-naive children with an anxiety disorder (mean 11.00 years +/- 2.54) are compared to 35 healthy age- and IQ-matched healthy children (mean 11.95 years +/- 2.36) on a virtual, computer-based equivalent of the Morris Water Maze task.
Results indicate that children with anxiety disorder exhibit overall impaired performance relative to the comparison group. Anxious children made more heading direction errors and had worse accuracy in completing trials relative to controls.
The results present novel evidence that spatial orientation deficits occur in pediatric anxiety.
Journal of Child Psychology and Psychiatry 08/2009; 50(10):1227-34. DOI:10.1111/j.1469-7610.2009.02112.x · 6.46 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Major questions remain about the exact role of hormones in cognition. Furthermore, the extent to which early perturbation in steroid function affects human brain development continues to be a wide open area of research. Congenital adrenal hyperplasia (CAH), a genetic disorder of steroid dysfunction characterized in part by in utero over-production of testosterone, was used as a natural model for addressing this question. Here, CAH (n=54, mean age=17.53, 31 female) patients were compared to healthy age- and sex-matched individuals (n=55, mean age=19.02, 22 female) on a virtual equivalent of the Morris Water Maze task [Morris, R., 1984. Developments of a water-maze procedure for studying spatial learning in the rat. J. Neurosci. Methods 11, 47-60], an established measure of sex differences in spatial cognition in rodents. Findings revealed that females with CAH with the most severe form of the disease and expected highest level of in utero exposure to androgens were found to perform similarly to both healthy males and CAH males, whereas strong sex differences were apparent in milder forms of the disorder and in controls. Moreover, advanced bone age, an indicator of long-term childhood exposure to testosterone was correlated with improved performance. The results indicate that individuals exposed to both excess androgens prenatally and prolonged exposure during childhood may manifest long-lasting changes in cognitive function. Such finding suggests a pivotal role of hormonal function on brain development in humans, mirroring results from the animal literature.