[The difficult child syndrome].

Many children are referred to the psychiatrist with the title of the "difficult child". Behind that popular and nonscientific description hide several major psychiatric syndromes, such as attention-deficit hyperactivity disorder, disruptive behavior disorders, mood disorders and posttraumatic stress disorder. This article reviews the different clinical faces of these disorders, their differential diagnoses, comorbidity and prognosis. These disorders are very prevalent and have long-term consequences on the process of development of the child. Acquaintance with the disorders, early diagnosis and treatment can prevent complications and improve the prognosis.