en psychiatry psychiatry Short Communication Short Communication <span style="font-size:14px;"><span style="font-family:Times New Roman;"><span style="line-height:14pt"><b><i><span style="color:blue">Background</span></i></b><i><span style="color:blue">:</span></i> The most common psychiatric disorder in childhood is Attention-deficit/hyperactivity disorder (ADHD). Researchers have studied the effects of micronutrients on ADHD in recent years, but vit D deficiency has received less attention. In this study, serum vit D levels were compared between healthy and ADHD children.</span><br> <span style="line-height:14pt"><b><i><span style="color:blue">Methods:</span></i></b> This case-control study was carried out, in 2020, on 6-to-12-years-old children. There were 45 children with ADHD in the case group and 45 healthy children in the control group. Intravenous blood samples were taken from each child to measure serum vitamin D levels. A p-value < 0.05 was considered as significant.<span style="font-size:10.0pt"></span></span><br> <span style="line-height:14pt"><b><i><span style="color:blue">Results:</span></i></b> Mean serum vit D levels in children with ADHD (17.34&plusmn;8.37 ng / ml) were significantly lower than those in the control group (23.02&plusmn;10.97 ng / ml) (P= 0.007). There were no significant differences in mean serum levels of vit D due to ADHD subtypes. Mean serum vit D levels were not significantly associated with the gender of children with ADHD. There was an inverse correlation between vit D levels and the severity of ADHD, but it was not statistically significant.<span style="font-size:10.0pt"></span></span><br> <span style="line-height:14pt"><b><i><span style="color:blue">Conclusion</span></i></b><i><span style="color:blue">:</span></i> The present study showed that children with ADHD had significantly lower serum vit D levels than healthy controls.<span style="font-size:10.0pt"></span></span></span></span><br> &nbsp; Attention-Deficit/Hyperactivity Disorder, Hyperactivity Disorder, Vitamin D, Psychiatric Disorders 681 686 http://caspjim.com/browse.php?a_code=A-10-2664-1&slc_lang=en&sid=1 Armon Massoodi armonmassoodi@gmail.com 100319475328460048412 100319475328460048412 No Social Determinants of Health Research Center, Health Research Institute, Babol Univrsity of Medical Sciences,babol,Iran Sakineh Javadian Koutanaei Javadian1939@yahoo.com 100319475328460048413 100319475328460048413 No Department of psychiatry, School of Medicine, Social Determinants of Health Research Center, Research Institute for Health, Shahid Yahya nezhad Hospital, Babol University of Medical Science, Babol, Iran. Zahra Faraz Zahra.faraz.khm1995@gmail.com 100319475328460048414 100319475328460048414 No Student Research Committee, Babol University of Medical Sciences, Babol, Iran Zahra Geraili Geraili.stat@gmail.com 100319475328460048415 100319475328460048415 No Social Determinants of Health Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran Seyedeh Maryam Zavarmousavi maryamzavarmousavi@gmail.com 100319475328460048416 100319475328460048416 Yes Department of Psychiatry, Shafa Hospital, Guilan University of Medical Sciences, Rasht, Iran