Objective: ADHD is a well known psychiatric disorder that begins in childhood and frequently persists into adulthood. In the last decade numerous studies have shown the importance of genetic factors in the etiology of ADHD. However other etiological factors seem to be involved. The aim of this study was to examine the frequency of some possible etiological factors for ADHD in Icelandic children diagnosed with ADHD. The study is descriptive.

Materials and methods: The participants were 196 children referred for suspected ADHD to the outpatient unit of the Department of Child and Adolescent Psychiatry, Landspitali University Hospital during a 2 year period 1998-1999. The participants had either ICD-10 or DSM-IV diagnosis of hyperkinetic disorder and/or ADHD and the information was obtained from patient case notes. Information provided by parents in a questionnaire concerning health in pregnancy and the perinatal period was retrospectively analysed.

Results: The main results show statistically significant increased risk for ADHD associated with several factors such as low birthweight, young age of the mother at the time of the child’s birth and Caesarian section, compared with reference groups such as mean values in all of the community. Other factors such as birthweight, alcohol or tobacco use in pregnancy, use of medication in pregnancy or vacuum extration did not show statistically significant association with ADHD.

Conclusion: The results indicate as some studies from other countries have suggested that an association exists between a number of factors in pregnancy, delivery and perinatal period and ADHD, even though there is still not enough evidence to confirm definite etiological factors.

Læknablaðið 2006; 92: 609-14