Attention deficit hyperactivity disorder (ADHD) in children, seasonal photoperiods, nocturnal movements and diurnal agitation.

OBJECTIVE: The main purpose of this study was to verify that the shortening photoperiods of winter contribute to increasing the nocturnal and diurnal agitation of children with ADHD and that lengthening photoperiods diminish it.
METHOD: TO VERIFY THIS HYPOTHESIS WE CHOSE A LOCATION WHERE DAYLIGHT TIMES DROP DRASTICALLY IN THE FALL: Edmonton (Canada). The study's sample was fifteen children, varying in age from 7 to 9 years (M=8.13 years old). The participants were divided into two clinical groups and one control group. The first clinical group was made up of five (n=5) children diagnosed with ADHD and treated with psychostimulants. The second clinical group was made up of five (n=5) children with ADHD not treated with psychostimulants. The control group was composed of five (n=5) children showing no signs of ADHD or psychopathologies. The intensity of diurnal agitation linked to ADHD was evaluated by teachers using the French version questionnaire (SWAN-F) at T1 (first day of experiment). The children's nocturnal movements were evaluated using actimetry. Their sleep quality was measured with a sleep agenda. These last two measurements were carried out for five consecutive days when the length of the photoperiod was at its shortest (end of December). The same procedures were repeated at the end of June (T2), when the photoperiod was at its maximum.
RESULTS: The principal results support the study's hypothesis and show a significant baseline difference (p=0.008) between the nocturnal motor movements of the ADHD children and those of the control children.
CONCLUSIONS: According to these results, this type of research should be reproduced in other Nordic countries and should include a larger sample group of children diagnosed with ADHD.