Assessment of Serum Melatonin Levels, Sleep Patterns, and Clinical Symptoms in Children with Autism Spectrum Disorder: A Case-Control Study

Objective: This study aims to evaluate the relationship between serum melatonin levels, sleep habits, and clinical features in children with autism spectrum disorder (ASD) compared to healthy controls. Methods: In accordance with DSM (The Diagnostic and Statistical Manual of Mental Disorders)-V, children aged 2-8 years diagnosed with autism spectrum disorder (n:38) and healthy children (n:33) of similar age and gender in the control group were evaluated. Vitamin D levels, ferritin, serum iron, and iron binding capacity of all participants were examined, as well as endogenous melatonin levels, and a pediatric sleep habits questionnaire was filled out. Autism Behavior Checklist (ABC-Autism Behavior Checklist) and The Modified Checklist for Autism in Toddlers (M-CHAT) were applied to the autism spectrum disorder group. The relationship between the blood values obtained and the completed questionnaire results was evaluated. Results: Melatonin levels were compared between the patients with autism spectrum disorder and the control group. In total, 71 participants were included in it. The gender of 81.7% (n=58) of the participants was male.The mean age of the autism spectrum disorder group was 44.4±20.4 months, and that of the control group was 51.2±20 months (p=0.104). When children’s sleep habits questionnaire data were compared between the two groups, the "daytime sleepiness" subscale score was higher in the control group, while the "bed-wetting" subscale score was higher in the autism spectrum disorder group (p=0.036 and p=0.008, respectively). No significant correlation was found between the questionnaire scores of the patients and their melatonin levels. Melatonin levels were on average 823.2±237.9 U/L in the autism spectrum disorder group and 677.4±254.7 U/L in the control group. This difference between the two groups was found to be statistically significant (p=0.027). When the participants were compared by dividing according to their gender, it was found that there was a difference between the two groups only in male patients (p=0.020). It was observed that there was no significant difference between girls in terms of melatonin levels (p=0.608). Conlucion: In the light of the data we obtained in our study, it was observed that there are sleep problems in autism spectrum disorder and therefore, melatonin levels measured during the daytime are higher than in healthy children. This makes us think that there may be desensitization to melatonin receptors in the ASD group, and the fact that melatonin levels differ according to gender, suggesting that melatonin treatment modalities applied in ASD patients may be regulated according to gender.