Medication use by adolescents and adults with fragile X syndrome

A review of the use of psychotropic medication to address challenging behaviour in neurodevelopmental disorders

Engagement in challenging behaviour (e.g., aggression, self-injury) is reported to occur in neurodevelopmental disorders such as intellectual disabilities (ID), autism spectrum disorder (ASD), and fragile X syndrome (FXS). Common interventions to address these behaviours include both behavioural and pharmacological approaches. Although psychotropic medications are commonly used to address challenging behaviour in ID, ASD, and FXS, demonstration of the effectiveness of treatment is limited. Furthermore, research examining interaction effects between psychotropic medication, challenging behaviour, and environmental events within specific neurodevelopmental disorders such as ID, ASD, and FXS is scarce. The purpose of this chapter is to provide an overview of challenging behaviour within ID, ASD, and FXS and of the effectiveness of psychotropic medication as an intervention for challenging behaviour within these neurodevelopmental disorders. Finally, research examining how psychotropic medication may impact the relationship between challenging behaviour and environmental events is reviewed.

Social Anxiety in Neurodevelopmental Disorders: The Case of Fragile X Syndrome

Despite significant advances in understanding and treating social anxiety in the general population, progress in this area lags behind for individuals with intellectual disability. Fragile X syndrome is the most common cause of inherited intellectual disability and is associated with an elevated prevalence rate of social anxiety. The phenotype of fragile X syndrome encompasses multiple clinically significant characteristics that are posed as risk markers for social anxiety in other populations. Here, evidence is reviewed that points to physiological hyperarousal, sensory sensitivity, emotion dysregulation, cognitive inflexibility, and intolerance of uncertainty as primary candidates for underlying mechanisms of heightened social anxiety in fragile X syndrome. A multilevel model is presented that provides a framework for future research to test associations.

Research Gaps in Fragile X Syndrome: An Updated Literature Review to Inform Clinical and Public Health Practice

OBJECTIVE

The phenotypic impact of fragile X syndrome (FXS) has been well-documented since the discovery of the fragile X messenger ribonucleoprotein 1 gene 30 years ago. However, gaps remain in clinical and public health research. The purpose of this literature review was to determine the extent to which these gaps have been addressed and identify targeted areas of future research.

METHODS

We conducted an electronic search of several scientific databases using a variety of key words. The search focused on 5 areas identified as research gaps by an earlier review: (1) diagnosis, (2) phenotypic presentation, (3) familial impact, (4) interventions and treatments, and (5) life span perspectives. Inclusion criteria included publication between 2014 and 2020, focus on human subjects, and publication in English. A total of 480 articles were identified, 365 were reviewed, and 112 are summarized in this review.

RESULTS

Results are organized into the following categories: (1) FXS phenotype and subtypes (FXS subtypes, medical profile, cognitive/developmental profile, social and behavioral profile); (2) needs of adults; (3) public health needs (clinical diagnosis and newborn screening, health care needs, and access); (4) treatment (treatment priorities, pharmacological treatments, and behavioral and educational interventions); and (5) families (economic burden and mother-child relationship).

CONCLUSION

Despite the progress in many areas of FXS research, work remains to address gaps in clinical and public health knowledge. We pose 3 main areas of focused research, including early detection and diagnosis, determinants of health, and development and implementation of targeted interventions.

Conducting In-Home Functional Analyses of Aggression and Self-Injury Exhibited by Boys with Fragile X Syndrome

OBJECTIVE

Boys with fragile X syndrome (FXS) are at increased risk for exhibiting aggression and self-injury that can be extremely disruptive to families. Few studies, however, have examined the extent to which social-environmental factors can influence these behaviors, particularly in home settings.

METHODS

Caregivers of 32 boys with FXS, aged 3 to 10 years, were coached by a board-certified behavior analyst to implement a functional analysis (FA) with their child in their home over 2 days. The functions identified in the FAs were validated by behavioral interventions conducted through telehealth over 12 weeks.

RESULTS

Social functions for aggression and self-injury were identified in 29 (90.6%) cases, with the most common functions identified being escape from demands/transitions and/or tangible reinforcement. Subsequent function-based behavioral interventions (i.e., functional communication training) implemented for 22 cases by telehealth resulted in decreased rates of aggression and self-injury by 74% to 100%.

CONCLUSION

These data underscore the significant impact that social-environmental factors can have on the development and maintenance of aggression and self-injury in FXS. Conducting early home-based behavioral interventions designed to increase functional communication skills may therefore be an effective solution for the treatment of aggression and self-injury in FXS in the long term.

Psychotropic Drug Treatment Patterns in Persons with Fragile X Syndrome

Objective: Psychiatric comorbidity is common in fragile X syndrome (FXS) and often addressed through pharmacological management. Here we examine data in the Fragile X Online Registry With Accessible Research Database (FORWARD) to characterize specific symptoms being treated with psychotropic medication, patterns of medication use, as well as the influence of gender, intellectual disability (ID), age, and autism spectrum disorder (ASD) diagnosis. Methods: Data were drawn from the 975 participants who have a completed clinician form. We explored the frequency of psychotropic medication use for the following symptom clusters: attention, hyperactivity, anxiety, hypersensitivity, obsessive-compulsive disorder (OCD), mood swings, irritability/agitation, aggression, and self-injury (IAAS). Results: A majority of participants (617 or 63.3%) were taking a psychotropic medication, including investigational drugs. Medications were often targeting multiple symptoms. Psychotropic medication use was more common in males, adolescents, and those with comorbid ID and ASD. Anxiety was the most frequently targeted symptom, followed by attention-deficit/hyperactivity disorder symptoms and IAAS. Selective serotonin reuptake inhibitors (SSRIs) were the most frequently prescribed medication class among all patients (n = 266, 43%), followed by stimulants (n = 235, 38%), each with no gender difference. Antipsychotics were the third most frequently prescribed medication class (n = 205, 33%), and were more frequently prescribed to males and those with ID and ASD. Conclusions: Anxiety, attention and hyperactivity were the most common symptom targets for psychopharmacologic intervention in FXS. Our results support clinical knowledge that males with comorbid ASD and ID have a more severe presentation requiring more intervention including medications. These results highlight the need for examination of symptom overlap and interaction.

Artificial intelligence-assisted phenotype discovery of fragile X syndrome in a population-based sample

PURPOSE

Fragile X syndrome (FXS), the most prevalent inherited cause of intellectual disability, remains underdiagnosed in the general population. Clinical studies have shown that individuals with FXS have a complex health profile leading to unique clinical needs. However, the full impact of this X-linked disorder on the health of affected individuals is unclear and the prevalence of co-occurring conditions is unknown.

METHODS

We mined the longitudinal electronic health records from more than one million individuals to investigate the health characteristics of patients who have been clinically diagnosed with FXS. Additionally, using machine-learning approaches, we created predictive models to identify individuals with FXS in the general population.

RESULTS

Our discovery-oriented approach identified the associations of FXS with a wide range of medical conditions including circulatory, endocrine, digestive, and genitourinary, in addition to mental and neurological disorders. We successfully created predictive models to identify cases five years prior to clinical diagnosis of FXS without relying on any genetic or familial data.

CONCLUSION

Although FXS is often thought of primarily as a neurological disorder, it is in fact a multisystem syndrome involving many co-occurring conditions, some primary and some secondary, and they are associated with a considerable burden on patients and their families.

Trajectories of Change in the Behavioral and Health Phenotype of Adolescents and Adults with Fragile X Syndrome and Intellectual Disability: Longitudinal Trends Over a Decade

This study examined trajectories of daily living skills, behavior problems, body mass index (BMI), and health conditions spanning nearly a decade in adolescents and adults with fragile X syndrome (N = 134; age range at study end = 19-49 years), examining influences of sex and autism spectrum disorder (ASD) symptoms. Hierarchical linear modeling revealed early increases in daily living skills, with decreases at older ages. Behavior problems became less severe over time, with some increases at older ages. Individuals gained weight and had increasing health problems over time. Fewer ASD symptoms were associated with greater daily living skills and fewer behavior problems at study start. This study offers some of the first prospective quantitative analyses of behavioral and health life course trajectories in FXS.

Examining the Specificity of Forms and Functions of Aggressive Behavior in Boys With Fragile X Syndrome

Limited information is available concerning the specificity of the forms and functions of aggressive behavior exhibited by boys with fragile X syndrome (FXS). To investigate these relationships, we conducted indirect functional assessments of aggressive behavior exhibited by 41 adolescent boys with FXS and 59 age and symptom-matched controls with intellectual and developmental disability (IDD) and compared the data between groups. Results showed that boys with FXS were more likely to exhibit specific forms of aggressive behavior (i.e., scratching others and biting others) compared to controls, but the sources of reinforcement identified for aggression were similar across groups. Boys with FXS who were prescribed psychotropic medications were more likely to be older and to exhibit more forms of aggression. The implications for the treatment of aggressive behavior during this critical developmental period in FXS are discussed.

Prevalence and Predictors of Anxiety Disorders in Adolescent and Adult Males with Autism Spectrum Disorder and Fragile X Syndrome

Anxiety disorders affect ~ 15-20% of youths without neurodevelopmental disorders, with persons having autism spectrum disorder (ASD) and fragile X syndrome (FXS) at elevated risk for anxiety disorders. Few studies have compared rates and predictors of anxiety disorders in adolescents with FXS or ASD. This study directly compares rates, predictors, and medication of anxiety disorders between age-matched, male adolescents with FXS (n = 31) or ASD (n = 20). Results indicate that 51.6% of FXS and 50.0% of ASD adolescents met criteria for an anxiety disorder. Cognitive scores and ASD severity did not predict anxiety. Of those with anxiety, ~ 40% of the FXS and 20% of the ASD participants were prescribed medications for anxiety.