Pharmacotherapy for Aggressive Behaviours in Persons with Intellectual Disabilities: Treatment or Mistreatment?

Background: Antipsychotic medications have been used extensively to treat aggressive behaviours in persons with intellectual disabilities (ID) when the main psychiatric diagnoses given to them in the past were schizophrenia, childhood psychoses and ID with behaviour problems. Today, antipsychotics are still estimated to comprise 30-50% of all the psychotropics prescribed for persons with ID, although the prevalence of psychotic disorders is only 3% in this population. The overuse of antipsychotics in persons with ID could be justified if their aggressive behaviours were associated with mostly psychotic disorders and not other psychiatric disorders or factors and if the anti-aggressive properties of the antipsychotics have been supported by basic research or reviews of clinical studies. Is that so? This article explores these questions.

Methods: The literature on aggressive behaviours, their associations with psychiatric disorders and other contributing factors and the past and current treatment options for aggressive behaviours in persons with and without ID was reviewed. Also, the literature on basic research regarding the brain receptors implicated in aggressive behaviours and the basic research and clinical studies on the anti-aggressive properties of antipsychotics was reviewed.

Results: Aggressive behaviours in persons with ID serve different functions and many factors contribute to their initiation, maintenance and exacerbations or attenuation including most of the psychiatric and personality disorders. Genetic disorders, early victimisation, non-enriched and restrictive environments during childhood or later on and traumatic brain injury, which are common in persons with ID, have been associated with aggressive behaviours and with mostly non-psychotic disorders in persons with and without ID. If the factors above and the knowledge derived from studies of domestic violence and premeditated aggression in persons without ID are considered and applied during the evaluation of the most severe aggressive behaviours in persons with ID, more appropriate and effective treatment than antipsychotics can be implemented. Basic research implicates mostly the GABA and the serotonin pre-post synaptic brain receptors influence the initiation, modulation or inhibition of aggression in animals. The anti-aggressive properties of the antipsychotics have not been supported by reviews of clinical studies and basic research is absent. Antipsychotics are the indicated treatment only for psychiatric disorders and for aggressive behaviours associated with psychotic disorders and psychotic features as activation of dopamine receptor leads to defensive aggression.

Conclusions: Most of the persons with ID and aggressive behaviours do not have a diagnosis of psychotic disorder and there is lack of strong evidence supporting the anti-aggressive properties of the antipsychotics. The overuse of antipsychotics in this population may be explained by the old, faulty notion that aggressive behaviour in persons with ID is mostly associated with psychotic disorders. Given the discrediting of this notion, the use of antipsychotics in persons with ID may, in some cases, be considered mistreatment rather than proper treatment. In order to reverse the practice of over-prescribing antipsychotics for aggressive behaviours in persons with ID, basic research information on aggression must be disseminated, the search for the 'quick fix' must be abandoned and the promotion of antipsychotics as anti-aggressive drugs must be discouraged. Matching the treatment with the variables contributing to the aggressive behaviours, seeking a long-term rather than a short-term solution and avoiding the promotion of only one type of treatment for all types of aggression might change the current practice and improve the quality of life for many persons with ID.