Epidemiology
ODD is a pattern of negative, defiant, disobedient, and hostile behavior, and it is one of the most prevalent disorders from preschool age to adulthood. This can include frequent temper tantrums, excessive arguing with adults, refusing to follow rules, purposefully upsetting others, getting easily irked, having an angry attitude, and acting vindictive. Children with ODD usually begin showing symptoms around 6 to 8, although the disorder can emerge in younger children too. Symptoms can last throughout teenage years. The pooled prevalence is 3.6% up to age 18 (Ezpeleta, et al. 2019). While adults can be affected by ODD, they often go undiagnosed if they were not diagnosed as children. There has been research to support that ODD is more common in boys than girls with a 2:1 ratio.Oppositional defiant disorder has a prevalence of 1% to 11%. The average prevalence is approximately 3.3%. Gender and age play an important role in the rate of the disorder. ODD gradually develops and becomes apparent in preschool years, often before the age of eight years old. However, it is very unlikely to emerge following early adolescence. There is a difference in prevalence between boys and girls, with a ratio of 1.4 to 1 before adolescence. However, girls prevalence tends to increase after puberty. Researchers have found that the general prevalence of ODD throughout cultures remains constant. However, the difference in ODD prevalence between sexes is only significant in Western cultures.
It is possible that there is a decreased prevalence of ODD in boys or an increased prevalence of ODD in girls in non-Western cultures, but it is also possible that the disorder is either over- or under-diagnosed in boys or girls, respectively, in Western cultures. Other factors can influence the prevalence of the disorder. Youths living in families of low socioeconomic status have a higher prevalence. Another factor is based on the criteria used to diagnose an individual. When the disorder was first included in the DSM-III, the prevalence was 25% higher than when the DSM-IV revised the criteria of diagnosis. The DSM-V made more changes to the criteria, grouping certain characteristics together in order to demonstrate that ODD display both emotional and behavioral symptomatology. In addition, criteria were added to help guide clinicians in diagnosis because of the difficulty found in identifying whether the behaviors or symptoms are directly related to the disorder or simply a phase in a childs life. Consequently, future studies may obtain results indicating a decline in prevalence between the DSM-IV and the DSM-V.

Signs and symptoms
The fourth revision of the Diagnostic and Statistical Manual (DSM-IV-TR) (now replaced by DSM-5) states that a person must exhibit four out of the eight signs and symptoms to meet the diagnostic threshold for ODD.