Circadian rhythms of saliva melatonin in ADHD, anxious and normal children.

BACKGROUND: Attention-deficit/hyperactivity disorder (ADHD) and anxiety disorders are the most frequent psychiatric disorders in children. Changes in rhythms of symptoms during the day may be influenced by genetic, biological and psychological factors. Some changes of melatonin rhythm may hypothetically change the activity of ADHD by changing arousal or in anxiety children by changing their emotional state. In our present study we identify one group of ADHD children combine type without comorbids, one group of anxiety children and a control group. Most changes of melatonin daily rhythm are supposed in the anxiety group, especially in sleeping time, and more prominent change in the ADHD group with prominent hyperactivity and conduct disorder symptoms. METHODS: Thirty-four ADHD and forty-three control children and eleven anxiety children, all 6-12 years old, participated in the study. The saliva specimens were collected in four different sessions during the school year, around the time of the spring and autumn equinox, when the natural light lasted 11.2 h ± 0.9 h. RESULTS AND CONCLUSIONS: In our study more symptoms of conduct disorder elevated positive or negative correlations between psychopathology and saliva level of melatonin in ADHD and anxiety samples. We hypothesize that co-morbidity of ADHD or anxiety with impulsivity and conduct disorders might have elevated correlations between psychopathology of ADHD or anxiety and plasma melatonin level.

The association between TaqI A polymorphism of ANKK1 (DRD2) gene and ADHD in the Czech boys aged between 6 and 13 years.

OBJECTIVE: The purpose of this study was the correlation of the combined type of ADHD in children and Taq IA polymorphism DRD2 gene. We hypothesized a positive correlation of DRD2 polymorphisms in the combined type of ADHD patients without co-morbidity. PATIENTS AND METHODS: Our research sample included 586 unrelated boys of the Czech origin aged between 6 and 13 years. The ADHD group consisted of 269 boys and the control group consisted of 317 boys. PCR detection of the DRD2 polymorphism was carried out by using primers, described by Grandy (Grandy et al. 1989). RESULTS: The comparison of genotype frequencies showed statistically highly significant difference between the studied groups (p<0.0001). A statistically significant difference was also found when the allelic frequencies between the two groups were compared (p<0.0001), with the A1 allele having a 4.359 fold higher risk of ADHD (Risk Ratio=4.359, 95% CI of RR=3.5753 to 5.3144, Odds Ratio= 7.7824; 95% CI of OR=10.315 to 13.6719). CONCLUSIONS: Our results presented a highly positive correlation between the combined type of ADHD without co-morbidity and ANKK l (DRD2) polymorphism .