The 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 onset, experiences exacerbation of baseline behavioural symptoms or does not respond to a well conducted behavioural approach (). In general, the psychiatric symptomatology does not vary greatly from one living environment to another, is accompanied by autonomic symptoms (eg, significant decrease or increase in appetite), includes acute psychomotor agitation or apathy, and does not respond to a behavioural approach.
Basic principles concerning the search for a psychiatric diagnosis in children with an intellectual disability
The main organic causes that might explain a behaviour disorder must be considered. For example, obstructive apneas could explain a sleep disorder, while physical or sexual abuse or chronic pain (eg, toothache, constipation) may be manifested by aggressive behaviour. A chronological link may exist between the onset of the behaviour disorder and the use of medication (eg, benzodiazepine resulting in a disinhibition).
The first step usually requires working closely with educators and caregivers involved with the care of the child, to adopt a behavioural approach or to make changes to the environment (). When the use of a behavioural approach alone does not suffice, a pharmacological approach may be indicated. While patients with an ID respond to psychotropic medications, the response is often inferior when compared with the population without an ID and side effects are more frequent. Medication must be introduced slowly, and its effectiveness monitored closely (ie, start low, go slow). Nonoptimal dosing or not allowing sufficient time to observe the effects after a change in medication are among the more frequent causes of failure of psychotropic drugs. If no underlying psychiatric illness has been identified, medication will be prescribed based on the patient’s symptoms (eg, agitation, aggressiveness), and should be administered in close collaboration with educators and families. Unfortunately, due to a lack of resources for this population, pharmacological intervention is increasingly used.
Clinical approach to a behaviour disorder in a child with an intellectual disability