Though it is true that "intra family marriages are common in certain communities and tribes in this part of the world", this is not so common in most of the Indian population. Nevertheless, we checked for the consanguinity status for all the families included in our study, including 3 Muslim probands out of 41 ADHD cases, and found the consanguinity status to be negative in all cases. Further, we have not noticed any single case of familial ADHD, where we can look for concentrated cognitive characteristics.

Comorbidity of ADHD and dyslexia is indeed a common observation and we excluded such ADHD cases from our study. Only "classical ADHD" cases were selected.

Wechsler Intelligence Scale for Children (WISC) was used for IQ evaluation of the children. WISC is a common test to evaluate a child’s cognitive and intellectual functioning and is an important tool for diagnosing learning disability(1). IQ status of the subjects was used to discriminate between mentally challenged individuals (with IQ <75) and normal children/adolescents with poor scholastic achievements (IQ >75). The diagnosis of ADHD was based on DSM-IV-TR, the Conners’ Parents and Teachers Rating Scale and WISC. Subjects for the association study were selected as per the criteria in Table I.

Kanchan Mukhopadhyay,
Manovikas Biomedical Research and
Diagnostic Center,
482, Madudah, Plot 1-24,
Sec.- J, E.M. Bypass,
Kolkata 700 107,
West Bengal, India.

1. Reading and learning disabilities. A Publication of the National Information Center for Children and Youth with Disabilities. FS17, 4th Edition, February 2004.