Mira Vasileva and colleagues in Germany and Australia recently compiled a Research Review for the Journal of Child Psychology and Psychiatry on the prevalence of mental disorders in children <7 years old. The researchers identified 10, relevant epidemiological studies reporting data on >18,000 children (aged 12-83 months) from 2006 to 2020. These studies captured data from eight different countries.
The pooled prevalence of mental disorders in this cohort was 20.1%. Most of these disorders were: anxiety disorders (8.5%), oppositional defiant disorder (4.9%) and attention-deficit hyperactivity disorder (4.3%). Depressive disorders were less common (1.1%).
Finally, they estimated that comorbidity was ~6.4%. Overall, Vasileva et al. found that the epidemiology of mental disorders in children <7 years was a neglected area of research. Yet worryingly, a significant number of children in this age group suffer from a mental disorder that requires age-adapted treatment.
Vasileva, M., Graf, R.K., Reinelt, T., Petermann, U. & Petermann, F. (2020), Research review: A meta‐analysis of the international prevalence and comorbidity of mental disorders in children between 1 and 7 years. J. Child Psychol. Psychiatr. doi: 10.1111/jcpp.13261.
Oppositional defiant disorder (ODD): ODD is a less severe form of conduct disorder characterised by a pattern of negativistic, hostile and defiant behaviour. The disturbance in behaviour causes clinically significant impairment in social, academic or occupational functioning and the behaviours do not occur exclusively during the course of a psychotic episode or mood disorder.