Background. The increasing incidence of autism spectrum disorder (ASD) is a common finding of many studies. Early diagnosis and appropriate treatment approaches for ASD can provide favourable clinical outcomes. This study aimed to determine the factors affecting the age at diagnosis, in children with ASD.

Methods. Two hundred and two cases diagnosed with ASD were included in the study, according to the DSM-5 diagnostic criteria, at the Mersin City Training and Research Hospital Child and Adolescent Psychiatry outpatient clinics, between April 2021 and August 2022. Clinical features and sociodemographic data that may be related to early diagnosis were investigated.

Results. The mean age at diagnosis was 36.76 ± 15.30 months. In 71.3% of cases parents were the first to suspect that children were developmentally different. In 38.1% of the cases, at least one of the parents denied the symptoms and evaluated their child`s development as age-appropriate. It was found that 32.7% of the cases evaluated by pediatricians and 32.5% of cases evaluated by family physicians, were referred to child psychiatry examination. The present study revealed that higher educational level of the father and the middlehigh socioeconomic status, were associated with early diagnosis. There was also a positive correlation between paternal age and age at diagnosis.

Conclusions. The age at diagnosis is below the target level for early diagnosis. Studies should focus on increasing awareness of health professionals and parents about ASD.

Keywords: autism, awareness, early diagnosis, sociodemographic factors