[Attention-deficit hyperactivity disorder or bipolar disorder in childhood?].

Attention-deficit hyperactivity disorder (ADHD) is considered one of the most common neurodevelopmental disorders of childhood, characterized by inattention and/or hyperactivity-impulsivity. Even though a strict definition of this entity is constantly sought, ADHD is an often redefined and reconceptualized syndrome. Epidemiological studies show large differences in the incidence, pointing out that the effort of actual taxonomic systems to offer objective diagnostic criteria have not yielded substantial results. Bipolar Disorder (BD) with onset in childhood is distinguished from the adult form by the scarcity of affective symptoms. Very often, neither depressive mood, nor hypomanic euphoria are in the front line being covered by irritability with crises of violence. Children or adolescents have consecutive cycles, which include brief episodes of depressive, hypomanic, manic or mixed periods without free intervals. There was a delay in the recognition of this clinical picture. Τhe diagnostic criteria in the actual taxonomic systems are not separated from those of adults and according to some studies the disorder is under diagnosed mainly in European countries. The contemporary literature deals largely with the relationship ADHD - BD in young people because the two disorders share the same clinical picture with slight variations. Τhe differential diagnosis in favor of BD is mainly based on the presence of affective disorders in the family. The main questions raised are whether there is comorbidity, whether ADHD is overdiagnosed against BD or whether ADHD represents a prodromal manifestation of early onset BD. Children with comorbid ADHD and BD tend to express mostly a stimulant phenotype with a chronic course and have higher rates of antisocial conduct disorder. This particular phenotype suggests a symptomatic continuum between ADHD and early onset BD which is possibly responsible for the difficulties met in differential diagnosis and differences in the rates of comorbidity. It seems that the earlier the onset of BD more often it is combined with symptoms of ADHD which often precede mood disorders. The relationship between BD and ADHD is not just a nosological problem but has important implications for treatment. The confusion regarding diagnostic evaluation and the relationship of these two clinical entities is reflected in the proposed course of therapy particularly with regard tο pharmacotherapy. Τhe elevated rates of comorbidity between ADHD and BD observed in the USA, but not in other countries, are possibly due to the frequent use of stimulants.The dilemmas that arise for the diagnosis of ADHD, BD and their relationship refer to the difficulty of defining the limits of normal and abnormal in the mental health of children and adolescents and of the construction of a taxonomic system that respects the particularities of this developmental age spectrum. To achieve this goal, the search for objectivity in diagnostic criteria is not sufficient but one must also keep in mind psychodynamic factors that put children at the heart of their personal history.