Opioid Antagonists May Reverse Endogenous Opiate “Dependence” in the Treatment of Self-Injurious Behavior

Buprenorphine in rats: potent analgesic or trigger for fatal side effects?

With ongoing animal welfare efforts, multimodal analgesia is often recommended to implement in study protocols. Buprenorphine with very potent analgesic effect is a standard opioid for the use in this context in rats. In this study, two rat strains (LEW/NHanZtm, n = 6 and Crl:CD(SD), n = 8) underwent orthopaedic surgery and received carprofen, buprenorphine and a local anaesthetic in a multimodal setup. Crl:CD(SD) rats showed severe side effects in the first 24 h after anaesthesia, predominantly manifesting in pica-behaviour and reaching humane endpoints in two of eight animals, while LEW/NHanZtm rats showed only slight depression in the first postoperative days. In the context of improving animal welfare in experimental studies, buprenorphine is highly recommended not to be used in male Crl:CD(SD) rats and should generally be used very carefully and only if required.

Comparison of Autistic Individuals Who Engage in Self-Injurious Behavior, Aggression, and Both Behaviors

BACKGROUND

Two of the most challenging behaviors exhibited by individuals on the autism spectrum are self-injurious behavior (SIB) and aggression. The aim of this study was to identify co-occurring symptoms, behaviors, and medical comorbidities that may provide insight into understanding and treating these behaviors.

METHOD

A large-scale online survey was used to collect data on symptoms, behaviors, and medically related comorbidities commonly reported in individuals with autism spectrum disorders (ASD). Based on responses from 2327 participants, individuals with ASD were divided into four categories: individuals who engaged in SIB only, individuals who engaged in aggression only, individuals who engaged in both behaviors, and individuals who engaged in neither behavior.

RESULTS

There were several characteristics and comorbidities associated with those who engaged in SIB only and in aggression only, in addition to those who engaged in both behaviors.

CONCLUSION

The findings in this study provide evidence to support at least two underlying causes of these behaviors (insensitivity to pain and reactions to food) as well as implications for treating them. Furthermore, several behaviors often observed during early childhood may be considered early predictors of these challenging behaviors.

The aetiology of social deficits within mental health disorders: The role of the immune system and endogenous opioids

The American National Institute for Mental Health (NIMH) has put out a set of research goals that include a long-term plan to identify more reliable endogenous explanations for a wide variety of mental health disorders (Insel, 2013). In response to this, we have identified a major symptom that underlies multiple mental health disorders - social bonding dysfunction. We suggest that endogenous opioid abnormalities can lead to altered social bonding, which is a symptom of various mental health disorders, including depression, schizophrenia and ASD. This article first outlines how endogenous opioids play a role in social bonding. Then we show their association with the body's inflammation immune function, and review recent literature linking inflammation to mental health 'immunophenotypes'. We finish by explaining how these immunophenotypes may be caused by alterations in the endogenous opioid system. This is the first overview of the role of inflammation across multiple disorders where we provide a biochemical explanation for why immunophenotypes might exist across diagnoses. We propose a novel mechanism of how the immune system may be causing 'sickness-type' behaviours (fatigue, appetite change, social withdrawal and inhibited motivation) in those who have these immunophenotypes. We hope that this novel aetiology can be used as a basis for future research in mental health.

An update on pharmacotherapy of autism spectrum disorder in children and adolescents

To date, no medication is proven to be effective in treating core symptoms of autism spectrum disorder (ASD). Psychotropic medications are widely used to target emotional and behavioural symptoms in ASD. This article reviewed evidence for pharmacotherapy, novel therapeutic agents, and Complementary and Alternative Medicine (CAM) in children and adolescents with ASD. Currently, only risperidone and aripiprazole have been approved by the US Food and Drug Administration (FDA) for treatment of irritability associated with ASD in children and adolescents. However, associated metabolic side-effects are concerning. Evidence supports use of methylphenidate and atomoxetine for attention deficit hyperactivity disorder (ADHD) symptoms and clonidine and guanfacine ER appear to be helpful. SSRIs are poorly tolerated and lack evidence in reducing restricted repetitive behaviours (RRB), anxiety, and depression. Buspirone shows promise in the treatment of RRB. The evidence is inconsistent for the effectiveness of anti-epileptic medications. Recent studies of glutamatergic, Gamma-aminobutyric acid (GABA)ergic, and cholinergic agents and oxytocin show inconsistent results. Despite wide use of CAM agents, the evidence is inconclusive. Melatonin can be helpful in reducing sleep problems. Overall, the evidence is limited for pharmacotherapy in children with ASD, and side-effects with long-term use can be burdensome.

Treatment options for the management of pervasive developmental disorders

Autism spectrum disorder (previously known as pervasive developmental disorders) is characterized by social communication deficits, impaired functioning, and restrictive or repetitive behaviors and interests. Patients with autism spectrum disorder also commonly experience core maladaptive behaviors such as aggression and irritability, self-injurious behaviors, hyperactivity, and sleep abnormalities. These behaviors may be sources of stress for caregivers and patients alike and may require pharmacologic management. Risperidone and aripiprazole are frequently used to treat both irritability and self-injurious behavior related to autism spectrum disorder. The opioid antagonist naltrexone has also been studied for self-injurious behaviors, although long-term data are lacking when used in the autism spectrum disorder population. Methylphenidate, atomoxetine, clonidine, and guanfacine are all potential options for the treatment of hyperactivity or attention-deficient hyperactivity disorder-like symptoms in patients with autism spectrum disorder. Lastly, melatonin is the most widely researched medication strategy for the management of sleep disorders in autism spectrum disorder. Future studies reviewing new pharmacologic treatment approaches in combination with non-pharmacologic therapies are warranted to ensure that target behaviors of autism spectrum disorder are appropriately managed.

Are opioid antagonists effective in attenuating the core symptoms of autism spectrum conditions in children: a systematic review

BACKGROUND

ASC (autism spectrum conditions) may result from a failure of striatal beta endorphins to diminish with maturation. Many symptoms of ASC resemble behaviours induced in animals or humans by opiate administration, including decreased socialisation, diminished crying, repetitive stereotypies, insensitivity to pain and motor hyperactivity. Naltrexone, an opioid antagonist, has been used in the management of children with ASC and can produce a clinically significant reduction in the serious and life-threatening behaviour of self-injury for individuals who have not been responsive to any other type of treatment and is important for this reason. It was therefore appropriate to reconsider the available evidence and a systematic review was undertaken.

METHODS

Four electronic databases were searched for relevant journal articles. In addition, cross-referencing of pertinent reviews and a hand search for articles in major international intellectual disability (ID) journals between the years 2010 and 2012 was carried out to ensure that all relevant articles were identified. We also searched databases for unpublished clinical trials to overcome publication bias. Each database was searched up to present (February 2013) with no restrictions on the date of publication. The search terms consisted of broad expressions used to describe ID and autistic spectrum disorder as well as terms relating to opioid antagonists and specific drugs. All studies identified by the electronic database search and hand search were examined on the basis of title alone for relevance and duplication. The abstracts of the remaining papers were then scrutinised against the inclusion criteria. Where abstracts failed to provide adequate information, the full texts for these papers were obtained. All the full texts were then evaluated against the inclusion proforma. Two reviewers carried out all the stages of the process independently. The reviewers met to discuss their selections and where disagreements arose, these were settled by discussion with a member of the study group. Data from each study meeting the inclusion criteria were extracted on a pre-piloted data extraction form. The quality of each study was further assessed using the Jadad scale, a tool developed to assess the quality of randomised controlled trials.

RESULTS

155 children participated in 10 studies; 27 received placebo. Of the 128 that received naltrexone 98 (77%) showed statistically significant improvement in symptoms of irritability and hyperactivity. Side effects were mild and the drug was generally well tolerated.

CONCLUSIONS

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. It is likely that a subgroup of children with autism and abnormal endorphin levels may respond to naltrexone and identifying the characteristics of these children must become a priority.

An update on pharmacotherapy for autism spectrum disorder in children and adolescents

PURPOSE OF REVIEW

Although there is no known efficacious pharmacotherapy for core symptoms of autism spectrum disorder (ASD), psychotropic medications are commonly prescribed for behavioral/emotional symptoms associated with ASD. We reviewed current evidence-based pharmacotherapy options and updates from recent noteworthy studies.

RECENT FINDINGS

Atypical antipsychotics, particularly risperidone and aripiprazole, are effective in reducing irritability, stereotypy and hyperactivity. Metabolic adverse events, including weight gain and dyslipidemia, are common. Methylphenidate is effective in reducing attention-deficit hyperactivity disorder (ADHD) symptoms. Atomoxetine and alpha-2 agonists appear effective in reducing ADHD symptoms. Selective serotonin reuptake inhibitors are not effective in improving repetitive behaviors in children with ASD, and frequently cause activating adverse events. Efficacy of antiepileptic drugs is inconclusive. Overall, efficacy and tolerability of pharmacotherapy in children with ASD are less favorable than data seen in typically developing children with similar symptoms. Newer agents, including glutamatergic agents and oxytocin, appear promising albeit with mixed results.

SUMMARY

Current evidence-based pharmacotherapy options in children with ASD are very limited, and many have substantial adverse events. Clinicians should use pharmacotherapy as a part of comprehensive treatment, and judiciously weigh risks and benefits. New pharmacotherapy options for core symptoms as well as co-occurring symptoms of ASD are in urgent need.

Are opioid antagonists effective in reducing self-injury in adults with intellectual disability? A systematic review

BACKGROUND

Self-injury in people with intellectual disability (ID) may be due to variety of factors both environmental and biological. As the drive in UK is to manage people with ID and problem behaviours in the community, it is important to critically examine all treatment options available. As abnormalities in the endogenous opioid system may be a factor in some people with ID, we undertook a systematic review to evaluate the evidence for the effectiveness of opioid antagonists.

METHODS

Four electronic databases were searched for relevant journal articles. In addition, cross-referencing of pertinent reviews and a hand search for articles in major international ID journals between the years 2010 and 2012 was carried out to ensure that all relevant articles were identified. We also searched databases for unpublished clinical trials to overcome publication bias. Each database was searched up to present (February 2013) with no restrictions on the date of publication. The search terms consisted of broad expressions used to describe ID and autistic spectrum disorder as well as terms relating to opioid antagonists and specific drugs. All studies identified by the electronic database search and hand search were examined on the basis of title alone for relevance and duplication. The abstracts of the remaining papers were then scrutinised against the inclusion criteria. Where abstracts failed to provide adequate information, the full texts for these papers were obtained. All the full texts were then evaluated against the inclusion proforma. Two reviewers carried out all the stages of the process independently. The reviewers met to discuss their selections and where disagreements arose, these were settled by discussion with a member of the study group. Data from each study meeting the inclusion criteria was extracted on a pre-piloted data extraction form. The quality of each study was further assessed using the Jadad scale, a tool developed to assess the quality of randomised controlled trials.

RESULTS

Out of 10 randomised control trials eight reported a reduction in the frequency of self-injurious behaviour. This meant that 62 participants out of 124 (50%) showed an improvement of which 61 were statistically significant. Forty-nine participants had autism. Eleven (9%) had minor side-effects. The improvement was more marked in people with severe and profound ID and was not affected by the coexistence of autism.

CONCLUSIONS

This review suggests that some people respond to opioid antagonists with a reduction in self-injury but the trials do not predict who they may be. Future research may identify this sub-group when opioid antagonists may prove to be a useful addition in the pharmacotherapy of self-injury.

Anger regulation style, anger arousal and acute pain sensitivity: evidence for an endogenous opioid "triggering" model

Findings suggest that greater tendency to express anger is associated with greater sensitivity to acute pain via endogenous opioid system dysfunction, but past studies have not addressed the role of anger arousal. We used a 2 × 2 factorial design with Drug Condition (placebo or opioid blockade with naltrexone) crossed with Task Order (anger-induction/pain-induction or pain-induction/anger-induction), and with continuous Anger-out Subscale scores. Drug × Task Order × Anger-out Subscale interactions were tested for pain intensity during a 4-min ischemic pain task performed by 146 healthy people. A significant Drug × Task Order × Anger-out Subscale interaction was dissected to reveal different patterns of pain intensity changes during the pain task for high anger-out participants who underwent pain-induction prior to anger-induction compared to those high in anger-out in the opposite order. Namely, when angered prior to pain, high anger-out participants appeared to exhibit low pain intensity under placebo that was not shown by high anger-out participants who received naltrexone. Results hint that people with a pronounced tendency to express anger may suffer from inadequate opioid function under simple pain-induction, but may experience analgesic benefit to some extent from the opioid triggering properties of strong anger arousal.

Recent research on aetiology, development and phenomenology of self-injurious behaviour in people with intellectual disabilities: a systematic review and implications for treatment

BACKGROUND

Behavioural interventions conceptualise self-injurious behaviour (SIB) as developing from early repetitive behaviours through acquisition of homeostatic functions in regulating stimulation and subsequent shaping into SIB through socially mediated or automatic operant reinforcement. Despite high success rates, such interventions rarely completely eliminate SIB, and overall effectiveness has not increased since the 1960s.

METHODS

Research (excluding studies of single genetic syndromes) on the early development, functional properties and phenomenology of SIB in persons with intellectual disabilities (IDs) published from 1999 to 2010 inclusive is reviewed.

RESULTS

Despite evidence to support the operant shaping hypothesis, in some cases tissue-damaging SIB, especially head-banging, emerges at a similar or younger age than stereotyped behaviours or 'proto-SIB', often associated with tantrums following frustrative non-reward and/or abrupt situational transitions. Many young children show undifferentiated patterns of responding in functional analyses of SIB, and SIB is associated with aggression and impulsivity as well as with repetitive behaviour.

CONCLUSIONS

One dynamic in the development of SIB may be Pavlovian conditioning of aggression, originally elicited by aversive events or frustrative non-reward, to stimuli associated with such situations. Integration into operant technology of interventions based on Pavlovian principles such as graduated exposure (with or without counterconditioning) to aversive stimuli may enhance the effectiveness of behavioural interventions.