T he diagnosis of an intellectual disability (ID) relates to a heterogeneous group of individuals, approximately 3% of the population, whose intelligence quotient is <70. Behaviour disorders are frequent in children with an ID, can create problems in everyday life and can mask, or reveal an organic or psychiatric illness. It is crucial to adopt a multidisciplinary approach in treating these behaviours.In the present review, we first describe some general concepts dealing with the management of behaviour disorders in children with an ID, and then provide an overview of, in our experience, the four most common of these disorders: sleep disturbances, agitation (as it relates to attention-deficit hyperactivity disorder [ADHD]), aggression and self-injury. The treatment of organic problems and psychiatric illnesses that may cause behaviour disorders is beyond the scope of the present article. The present article is based on a conventional and complete literature review, with many of the practical suggestions based on the experience of the authors (ie, group consensus).
General concepts
assessmentThe first step is to obtain an adequate medical history including onset of the behaviour disorder, evolution over time, extenuating or aggravating factors (eg, environmental stressors that could be impacting the child), functional impairment, a family history of psychiatric problems and the impact of the child's behavioural difficulties on other family members. It is also important to have information on the individual's level of functioning including cognitive, adaptive, social-functioning, levels of receptive understanding and expressive language (1). A thorough physical examination is required in all cases.In cases where parents or tutors 'no longer recognize the child' and there are, for example, autonomic symptoms such as loss of appetite combined with a loss of weight or marked changes in sleep habits, a specific questionnaire dealing with psychiatric symptoms must be completed. A family history of depression, loss of interest in favourite activities, evidence of sadness and recent irritability should suggest the possibility of a depression. In investigating a possible anxiety problem, it is important not only to consider the family history, but also the avoidance of specific situations, difficulties with transitions, difficulties encountered in distancing oneself from attachment figures or the presence of adrenergic symptoms (eg, tachycardia, tremor) during a crisis. A bipolar illness must be considered in the presence of a family history or severe agitation cycles alternating with periods of apathy.In most circumstances, a suspected psychiatric etiology would require evaluation and management by a child psychiatrist. The prevalence rate of psychiatric disturbances, in the population of children with an ID, is 20% to 35%, that is, three to five times higher than that for the general population. It is important to rule out the possibility of a psychiatric disturbance when the patient shows behavioural symptoms of recent...