<unk>  is a pattern of negativistic,<unk> , disobedient and hostile behaviour, and is one of the most prevalent disorders from preschool age to adulthood.<unk>  is marked by<unk>  and disobedient behaviour towards authority figures. This can include: frequent temper tantrums, excessive arguing with adults, refusing to follow rules, acting in a way to purposely upset others, getting easily irked, having an angry attitude, and acting vindictive. Children with<unk>  usually begin showing symptoms around 6 to 8, although the disorder can emerge in younger children, too. Symptoms can last throughout the teen years. The pooled prevalence is 3.6% up to age 18 (Ezpeleta, et al. 2019). While adults can be affected by<unk> , adults with<unk>  who were not diagnosed as children often go undiagnosed. There has been research to support that<unk>  is more common in boys than girls with a 2:1 ratio.<unk>  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. In fact,<unk>  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. The ratio of this prevalence is 1.4 to 1 with it being more prevalent in boys than in girls, before adolescence. However, girls' prevalence tends to increase after puberty. When researchers observed the general prevalence of<unk>  throughout cultures, they noticed that it remained constant. However, the sex difference in<unk>  prevalence is only significant in Western cultures. There are several possible explanations for this difference; it is possible that in non-Western cultures there is a decreased prevalence of<unk>  in boys or an increased prevalence of<unk>  in girls; or 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. One of these factors is the socioeconomic status. 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<unk>  display both emotional and behavioural 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 child's life. Consequently, future studies may obtain results indicating a decline in prevalence between the DSM-IV and the DSM-V due to these changes.
Oppositional defiant disorder
Attention deficit hyperactivity disorder
Conduct disorder
Tourette syndrome
Personality development disorder
Motivational deficiency disorder
Obsessive–compulsive personality disorder
Obsessive–compulsive disorder