門田 行史

OBJECTIVE: This study undertook neuropharmacological research on the clinical course of controlled medication discontinuation to guide practitioners who are considering stopping medications for youths with attention-deficit hyperactivity disorder (ADHD). METHODS: This study analyzed the data for 14 ADHD children (12 male and 2 female) in two datasets: The children prescribed methylphenidate (MPH) were at an initial mean age of 7.5 years (SD = 1.70, range: 6-11) with a mean ADHD-Rating Score (ADHD-RS) of 26.6 (SD = 8.64, range 15-40). The children who discontinued MPH based on clinical judgment were at a mean age of 12.21 years (SD = 2.12, range: 8-15) with a mean ADHD-RS of 15.9 (SD = 6.86, range 5-27). The go/no-go task was used to assess response inhibition, while functional near-infrared spectroscopy (fNIRS) was used to measure cerebral hemodynamics. Oxygenated hemoglobin (Oxy-Hb) values from fNIRS data were analyzed for each subject, focusing on past and current measurements. Baseline was set at 10 s pre-task, with interval means from 4 to 24 s analyzed. One-sample t-tests were used to evaluate brain activity magnitude. RESULTS: The results of the study demonstrate that the children who had discontinued the medication exhibited activation in specific brain regions including the frontopolar cortex and the right ventrolateral prefrontal cortex. Activation (t = 2.363, p = 0.034, Cohen's d = 0.632) was found especially in the right dorsolateral prefrontal cortex during the performance of the go/no-go task. These activated areas were consistent with those observed in a previous study comparing brain activity during a go/no-go task between children with ADHD and healthy children. CONCLUSION: The present study showed differences in cerebral hemodynamics before and after discontinuation of MPH in ADHD children whose ADHD symptoms did not recur after MPH was discontinued. In the near future, further investigations that include control groups will be conducted to demonstrate the effects of MPH prior to discontinuation based on the changes in cerebral blood flow in the right prefrontal cortex, which is involved in behavioral inhibition, as observed in this study. This and future research will facilitate the development of criteria for discontinuing treatment.

BACKGROUND: Behavioral problems of foster children are an important issue for the maintenance of the foster care system, but they have not been adequately studied in Japan. We used the Eyberg Child Behavior Inventory (ECBI) to investigate behavioral problems among foster children and to examine associated factors. METHODS: Twenty-nine foster children and their foster parents and 479 non-foster children and parents were recruited for the foster and control groups, respectively. Both groups underwent statistical comparative analyses using data from their ECBI assessments. The ECBI has two scales: the Intensity Scale quantifies the severity of child behavioral problems, and the Problem Scale captures the caregiver's perceived difficulties handling each behavior. We conducted a retrospective investigation of the background of the foster parent-child pairs to explore potential causal relationships with behavioral problems. RESULTS: The mean intensity score for the foster group was significantly higher than that for the control group (p = 0.001). The mean problem scores for the foster group and the control group were not significantly different (p = 0.79). In the foster group, the retrospective investigation revealed two children with neurological or neurodevelopmental disorders, 17 with histories of abuse, and 10 with other issues. CONCLUSION: Intensity scores showed severe behavioral problems among foster children, perhaps caused by neurological disorders, abuse, parental mental health, or economic hardship. Problem scores showed no significant differences between groups. It can therefore be posited that foster parents might exhibit a more lenient parenting style when dealing with children who have a history of abuse by their biological parents.