Psychiatric comorbidity in Korean children and adolescents with attention-deficit hyperactivity disorder: psychopathology according to subtype.

It is well-known that more than 50% of attention-deficit hyperactivity disorder (ADHD) cases also have comorbid psychiatric disorders. We evaluated the comorbid psychopathology of Korean children and adolescents with ADHD using a standardized diagnostic instrument. The Korean Kiddie-Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version (K-SADS-PL-K) was administered and completed in 105 patients who had been referred to the outpatient and inpatient clinics at the Samsung Medical Center from March 2004 to May 2005. All of the cases were diagnosed as ADHD according to DSM-IV criteria. We analyzed their clinical characteristics and psychiatric comorbidities, and assessed the correlation of any comorbidity with gender, age and ADHD subtype. Among our 105 participants, 70 (66.7%) subjects were diagnosed with combined-type ADHD, 22 (21.0%) were the predominantly inattentive type, only 1 (1.0%) was determined to have the predominantly hyperactive-impulsive type of ADHD, and 12 (11.4%) were classified as not otherwise specified (NOS) ADHD. Eighty (76.2%) subjects had at least one comorbid disorder such as oppositional defiant disorder (n = 53, 50.5%), anxiety disorders (n = 35, 33.3%) and affective disorders (n = 15, 14.3%). Our patients ranged in age from five to 16 years. Among the factors including gender, age, and ADHD subtype, ADHD subtype was the only one significant to comorbidity in our study. The results of this study suggest that psychiatric comorbidity in Korean children with ADHD is similar to the results of previous studies in western countries. Out of all the ADHD subtypes, the combined-type group had a significantly higher ratio of comorbid disorders and psychopathologies.