“Naltrexone may improve hyperactivity and restlessness in children with autism but there was not sufficient evidence that it had an impact on core features of autism in majority of the participants”.
That was the conclusions reached by Ashok Roy and colleagues* who looked at the collected data so far on the use of the opioid antagonist naltrexone in cases of pediatric autism.
More typically used to manage opioid and alcohol dependence, naltrexone belongs to a class of medicines which primarily act by blocking the opioid receptors we all have distributed in various parts of the body that are variably linked to feelings of euphoria, sedation and analgesia (pain relief).
With interest perhaps waning in naltrexone in recent years as a function of the myriad of other pharmacotherapeutics under investigation with autism in mind and the association between naltrexone use and hypotheses such as the opioid-excess theory of autism, the review by Roy and colleagues provides a timely reminder on the potential role of naltrexone for some people with autism.
Based on work started in the late 1970s hinting that there may overlap between some of the characteristics commonly observed in autism and that of opioid addiction, various research suggested there may be issues with some of the body’s own opioid-type chemicals called the endorphins in cases of autism. Coupled with speculation on the possible effects of external sources of opioid-like compounds derived from certain foods, naltrexone began to find some favour as an intervention option for autism, particularly where aggression and self-injury were common. The review by Roy and colleagues suggests that further investigations may be indicated on naltrexone in order to determine potential best-responders to this type of pharmacotherapy.
In more recent years, attention has also turned to the use of low-dose naltrexone (LDN) as a potential therapeutic option for autism following reports of successful use of lower doses of the drug for a variety of autoimmune related conditions such as Crohn’s disease. The implication being that one or more of the various immune system related findings highlighted in cases of autism, may offer additional targets for drugs such as naltrexone or that naltrexone may potentially be impacting on comorbid autoimmune conditions noted in some people with autism with a knock-on effect to behavioural symptoms. Further investigations are again required.
* Roy A. et al. Are opioid antagonists effective in attenuating the core symptoms of autism spectrum conditions in children: a systematic review. J Intellect Disabil Res. 2014 Mar 4.
Further commentary on this study can be found at: http://questioning-answers.blogspot.com/2014/04/new-life-for-naltrexone-and-autism.html