According to the literature, Attention Deficit Hyperactivity Disorder (ADHD) is one of the most common neurobiological disorders in childhood which also persists during adolescence and adulthood in approximately 2/3 of cases in most studies, either as a full blown disorder (about 15% retain the full diagnosis by age 25 years) or in partial remission (50%), although symptoms appear to reduce as people grow older; nonetheless, they still impair their function in everyday life and other aspects of their life. Impairments include problems with self-esteem, personal distress from the symptoms, difficulties in social interactions and peer or siblings' relationships, behavioural problems, and the development of co-morbid psychiatric syndromes.

In childhood ADHD is identified far more frequently in boys than girls. This is however considered plasmatic, for several reasons: boys may be more hyperactive and more aggressive than girls; most affected girls frequently   have the inattentive subtype of ADHD, showing lower rates of hyperactivity and comorbids than males; girls rather suffer more from internalizing problems, chronic fatigue and inattention; they cope with the disorder better and get diagnosed later in their life or remain undiagnosed. On the other hand, health care personnel are less aware of ADHD in girls thus they are less likely to suspect the disorder and refer girls for confirmation of diagnosis and treatment

Although, ADHD is one of the most thoroughly studied and established pediatric mental disorders, worldwide, it is still not entirely understood by the community, neither has been accepted as a psychiatric entity by all the scientific and social groups. No doubt, within the last five years, ADHD awareness has been progressively increased by the intense efforts of several groups of experts in the field, along with ADHD societies and organizations, who undertook the task to educate and sensitize those involved in referring, diagnosing, and managing children with ADHD. Despite of that, the disorder still remains underdiagnosed in many countries including Greece.

Children with ADHD are usually seen by specialists at the age of 3 to 7 years. In most of the cases, the recognition of the problem coincides with the initiation of the primary school, because of the increased demands posed on child's concentration, organization and compliance.

Since the core symptoms of ADHD, e.g. attention deficit, impulsivity, and hyperactivity, are generally common among most children in early life, the diagnosis is often overlooked, since it is not strictly defined "what is normal" in an infant's behavior. Besides, in some cases, the impact of ADHD itself on child's behavior, social adjustment or school achievements is attributed to comorbids that coexist with the disorder. Thus, ADHD is very often undiagnosed or false diagnosed, and even if diagnosed early in a child's life, it is very likely not to be properly managed, due to lack of a multimodal programme which is extremely important for the quality of child's future life. It has to be stressed out that early diagnosis and proper treatment of ADHD help sufferers reach their potentials and live successful and happier lives.