Selective serotonin reuptake inhibitors for the treatment of autism spectrum disorders

Investigational drugs in early-stage clinical trials for autism spectrum disorder

Introduction: Pharmacologic interventions in Autism Spectrum Disorder (ASD) have historically focused on symptom-based approaches. However, a treatment for the core social deficits has remained unidentified. While a definitive theory for the cause of ASD is not yet known, recent advances in our understanding of ASD pathophysiology have opened the door for research on new pharmaceutical methods to target core symptomology. Areas covered: Herein, we review the novel pharmacologic therapies undergoing early-stage clinical trials for the treatment of the social symptoms associated with ASD. Specifically, these strategies center on altering neurologic excitatory and inhibitory imbalance, neuropeptide abnormalities, immunologic dysfunction, and biochemical deficiencies in ASD. Expert opinion: Utilizing the growing field of knowledge regarding the pathological mechanisms and altered neurobiology of individuals with ASD has led to the development of many innovative pharmaceutical interventions. Clinical trials for neurobiologic and immunologic targets show promise in impacting the social behavior and processing deficits in ASD but need evaluation in larger clinical trials and continued biomarker development to more effectively and consistently assess pharmacologic effects. Additionally, evaluating patient-specific drug responsivity and integrating behavioral intervention in conjunction with pharmacologic treatment is crucial to developing a successful approach to ASD treatment.

Cannabinoid type-1 receptor signaling in central serotonergic neurons regulates anxiety-like behavior and sociability

The endocannabinoid (eCB) system possesses neuromodulatory functions by influencing the release of various neurotransmitters, including γ-aminobutyric acid (GABA) and glutamate. A functional interaction between eCBs and the serotonergic system has already been suggested. Previously, we showed that cannabinoid type-1 (CB1) receptor mRNA and protein are localized in serotonergic neurons of the raphe nuclei, implying that the eCB system can modulate serotonergic functions. In order to substantiate the physiological role of the CB1 receptor in serotonergic neurons of the raphe nuclei, we generated serotonergic 5-hydroxytryptamine (5-HT) neuron-specific CB 1 receptor-deficient mice, using the Cre/loxP system with a tamoxifen-inducible Cre recombinase under the control of the regulatory sequences of the tryptophan hydroxylase 2 gene (TPH2-CreER (T2)), thus, restricting the recombination to 5-HT neurons of the central nervous system (CNS). Applying several different behavioral paradigms, we revealed that mice lacking the CB1 receptor in serotonergic neurons are more anxious and less sociable than control littermates. Thus, we were able to show that functional CB1 receptor signaling in central serotonergic neurons modulates distinct behaviors in mice.

Psychopharmacological prescriptions for people with autism spectrum disorder (ASD): a multinational study

RATIONALE

Previous studies on psychotropic drugs prescribing in autism spectrum disorder (ASD) were from the USA or the UK. However, these studies may not be generalizable to other countries. There is a need to understand the extent of psychopharmacological prescribing for ASD treatment at a multinational level to identify areas of prescribing which lack evidence.

METHODS

We used the IMS Prescribing Insights database to investigate psychotropic drugs prescribing patterns for ASD treatment in children and adults in 2010-2012. Data were obtained from Europe (France, Germany, Italy, Spain and UK), South America (Mexico and Brazil), North America (Canada and USA) and Asia (Japan).

RESULTS

North American countries have the highest prescription rates, followed by the European and South American countries. Prescribing rates were higher in children compared to adults in individual countries. The most commonly prescribed drug for ASD was risperidone in young people (except in UK and Japan). In the UK, methylphenidate (34 %) was the most commonly prescribed for young people and haloperidol (44.1 %) in Japan. In adults, the most commonly prescribed drug class was antipsychotics and particularly risperidone (thioridazine and ziprasidone were the most prescribed antipsychotics in Brazil and USA, respectively).

CONCLUSION

There is variation in medication prescription for people with ASD among countries, which may be attributable to diagnostic criteria, clinical guidelines or health care systems. However, there is a lack of evidence of efficacy and safety for many psychotropic drugs prescribed for people with ASD. Research is needed to bridge the evidence gaps in prescribing.