The prevalence rates of attention deficit hyperactivity disorder (ADHD), depression, anxiety and suicide are increasing in patients with atopic dermatitis (AD), although no research has systematically examined these trends yet. Here, we explore the prevalence of the occurrence of comorbidities, such as ADHD, depression, anxiety and suicide with AD. We searched seven electronic databases from inception to October 2022 to identify relevant studies, and the Agency for Healthcare Research and Quality (AHRQ) and Newcastle–Ottawa Scale (NOS) tools were used to assess the quality of observational studies. Statistical analysis was performed using R software. Publication bias was evaluated using Egger's and Begg's linear tests. The global prevalence rates of ADHD, depression, anxiety and suicidal ideation in patients with AD were 7%, 17%, 21% and 13%, respectively, between 1998 and October 2022. Among children (aged <18 years), North American children with AD had the highest prevalence rates of ADHD (10%), depression (13%) and anxiety (20%). Among the adult (aged ≥18 years) population, patients with AD in Africa had the highest prevalence rates of depression (36%) and anxiety (44%), while Asian adults with AD had the highest prevalence rates of ADHD (7%) and suicidal ideation (20%). These results highlight the high prevalence and comorbidity rates of mental illnesses with AD, which should be brought to the attention of patients with AD and their physicians.