The aim of this study was to investigate the psychiatric problems and characteristics among children of child abuse (CA). Specifically, the authors investigated whether attention-deficit/hyperactivity disorder (ADHD) symptoms were exhibited before or after CA. A total of 39 abused child inpatients who were treated at Aichi Children's Health and Medical Center, Aichi, Japan, (mean age, 10.7 ± 2.6; mean IQ scores, 84.1 ± 19.3) were included in the study. The most frequent diagnosis was dissociative disorder in 59% of abused subjects. ADHD was diagnosed in 18% of abused subjects, and 71% of ADHD children had comorbid dissociative disorder. A total of 67% of all CA subjects fulfilled the ADHD criteria A according to DSM-IV-TR, however, only 27% of those fulfilled the criteria before CA. The subjects of dissociative disorder fulfilled ADHD criteria A more frequently than those of non-dissociative disorder (P = 0.013), and this result led to an increase in the frequency of the apparent ADHD. The rate of ADHD-suspected parents in the subjects who fulfilled ADHD criteria A after CA was significantly lower than those who fulfilled it before CA (P = 0.005). While it is difficult to distinguish ADHD from dissociative disorder, abused children may have increased apparent ADHD due to dissociative disorder. Further studies should be conducted in order to explore the distinct biological differences between ADHD before CA and the subjects who fulfilled ADHD criteria A after CA.