Interaction between the Val158Met catechol-O-methyltransferase gene variant and second-generation antipsychotic treatment on blood pressure in children

Adverse Drug Reactions of Olanzapine, Clozapine and Loxapine in Children and Youth: A Systematic Pharmacogenetic Review

Children and youth treated with antipsychotic drugs (APs) are particularly vulnerable to adverse drug reactions (ADRs) and prone to poor treatment response. In particular, interindividual variations in drug exposure can result from differential metabolism of APs by cytochromes, subject to genetic polymorphism. CYP1A2 is pivotal in the metabolism of the APs olanzapine, clozapine, and loxapine, whose safety profile warrants caution. We aimed to shed some light on the pharmacogenetic profiles possibly associated with these drugs’ ADRs and loss of efficacy in children and youth. We conducted a systematic review relying on four databases, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 recommendations and checklist, with a quality assessment. Our research yielded 32 publications. The most frequent ADRs were weight gain and metabolic syndrome (18; 56.3%), followed by lack of therapeutic effect (8; 25%) and neurological ADRs (7; 21.8%). The overall mean quality score was 11.3/24 (±2.7). In 11 studies (34.3%), genotyping focused on the study of cytochromes. Findings regarding possible associations were sometimes conflicting. Nonetheless, cases of major clinical improvement were fostered by genotyping. Yet, CYP1A2 remains poorly investigated. Further studies are required to improve the assessment of the risk–benefit balance of prescription for children and youth treated with olanzapine, clozapine, and/or loxapine.

The FTO rs9939609 Variant Is Associated with Cardiometabolic Disease Risk and Dietary Energy Intakes in Children with Mental Health Disorders

Background

Second-generation antipsychotics (SGAs) are used to treat children for mental health disorders but in some children they cause cardiometabolic complications including weight gain and type 2 diabetes. Genetic variants can place a child at risk of developing these metabolic complications. The fat mass and obesity-associated (FTO) rs9939609 A allele has been associated with obesity and dietary energy intakes in healthy children but its relation to metabolic complications in SGA-treated children is not known.

Objectives

This study investigated the association of the FTO rs9939609 variant and SGA treatment with cardiometabolic complications and dietary intakes in children with mental health disorders.

Methods

A cross-sectional population of children (≤18 y; n = 506) with mental health disorders that were SGA-treated (n = 197) and SGA-naïve (n = 309) were recruited through the Department of Psychiatry at BC Children's Hospital. Dietary intakes were estimated using 3-d food records in a subset of children (n = 73).

Results

Genotype frequencies were not different between SGA-treated (TT genotype 42.6%, TA genotype 38.6%, AA genotype 18.8%) and SGA-naïve (TT 41.1%, TA 39.5%, AA 19.4%) children. Children with the A allele had lower BMI z-sores compared with the TT genotype (0.84 ± 1.19 compared with 1.19 ± 1.36; P = 0.005, adjusted for ethnicity). We observed an interaction between FTO genotype and SGA status on fasting glucose (P = 0.036). SGA-naïve children with the A allele had higher fasting glucose than those with the TT genotype (4.96 ± 0.35 compared with 4.81 ± 0.35 mmol/L; P = 0.001), in adjusted models (age, sex, ethnicity, and BMI z-score). This was not observed in SGA-treated children. Children with the A allele had higher daily total energy intakes compared with the TT genotype (1994 ± 619 compared with 1814 ± 484 kcal/d; P = 0.048), in adjusted models (age, sex, ethnicity, and BMI z-score); no effect of SGA-treatment was observed.

Conclusions

Our findings suggest the A allele of the FTO rs9939609 variant is associated with higher BMI in children with mental health disorders, but only in those not treated with SGAs.

Pharmacogenomic Studies in Intellectual Disabilities and Autism Spectrum Disorder: A Systematic Review

BACKGROUND

Individuals with intellectual disability (ID) and autism spectrum disorder (ASD) often receive psychotropic medications such as antipsychotics and antidepressants to treat aberrant behaviors and mood symptoms, frequently resulting in polypharmacy and drug-related adverse effects. Pharmacogenomic (PGx) studies with ASD and/or ID (ASD/ID) have been scarce despite the promise of optimizing treatment outcomes. We reviewed the literature on PGx studies with antipsychotics and antidepressants (e.g., treatment response and adverse effects) in ASD/ID.

METHODS

We performed a systematic review using MEDLINE, Embase, and PsycINFO, including peer-reviewed original articles in English referring to PGx in the treatment of ASD/ID in any age groups (e.g., treatment response and adverse effects).

RESULTS

A total of 28 PGx studies using mostly candidate gene approaches were identified across age groups. Notably, only 3 studies included adults with ASD/ID while the other 25 studies focused specifically on children/adolescents with ASD/ID. Twelve studies primarily investigated treatment response, of which 5 and 6 studies included patients treated with antipsychotics and antidepressants, respectively. Most interesting results for response were reported for 2 sets of candidate gene studies, namely: (1) The DRD3 Ser9Gly (rs6280) polymorphism was examined in patients treated with risperidone in 3 studies, 2 of which reported an association with risperidone treatment response and (2) the SLC6A4 5-HTTLPR polymorphism and treatment response to antidepressants which was investigated in 4 studies, 3 of which reported significant associations. In regard to side effects, 9 of 15 studies focused on hyperprolactinemia in patients treated with risperidone. Among them, 7 and 5 studies examined the impact of CYP2D6 and DRD2 Taq1A polymorphisms, respectively, yielding mostly negative study findings.

CONCLUSIONS

There is limited data available on PGx in individuals with ASD/ID and in particular in adults. Given the potential for PGx testing in improving treatment outcomes, additional PGx studies for psychotropic treatment in ASD/ID across age groups are warranted.

Treatment-related weight gain and metabolic complications in children with mental health disorders: potential role for lifestyle interventions

Over 1 million Canadian children are estimated to have a mental health disorder, which are commonly treated with medications, such as second-generation antipsychotics (SGAs). Estimates suggest that SGA prescriptions to children are increasing in Canada. Although these medications are important and lifesaving components of psychiatric treatment, they are not without side effects. For some children, SGA treatment is associated with adverse metabolic complications including rapid weight gain, dyslipidemia, elevated blood pressure, and risk for type 2 diabetes. It is not clear why these complications develop, but it is assumed that SGAs stimulate appetite and food intake, and reduce resting energy expenditure leading to weight gain and that the metabolic complications occur secondary to the weight gain. Understanding the mechanisms underlying these complications is key to being able to identify children at risk and prevent and optimize treatment. In this narrative review, we provide an overview of the literature pertaining to the weight gain and metabolic complications in children treated with SGAs, highlighting the scope of the problem and the current limited research on how diet and physical activity can be used to prevent or lessen the severity of the metabolic complications and improve the long-term health trajectories of SGA-treated children. Novelty: Children are increasingly being treated with second-generation antipsychotics for mental health disorders. Dietary and physical activity assessments are not commonly considered in clinical settings. Randomized controlled trials of lifestyle interventions are needed to determine the effectiveness of mitigating the cardiometabolic complications in second-generation antipsychotic-treated children.

Risperidone But Not Quetiapine Treatment Is Associated With Increased Appetite But Not Satiety Hormones in Children During An Oral Glucose Tolerance Test: A Pilot Study

BACKGROUND

Second-generation antipsychotics (SGAs) are commonly used to treat children with mental health conditions (MHCs) but are associated with adverse effects including obesity, hypertension, dyslipidemia, and type 2 diabetes. The mechanisms underlying these complications are unknown, but it has been suggested that SGAs increase appetite leading to weight gain. The present objective was to perform a pilot study to investigate appetite and satiety hormones in SGA-treated (risperidone or quetiapine) and SGA-naive children with similar mental health conditions.

METHODS

Oral glucose tolerance tests (OGTTs) were conducted in SGA-naive (n = 18), risperidone-treated (n = 20), and quetiapine-treated (n = 16) children recruited from the British Columbia Children's Hospital Psychiatry Department. Over 5 time-points during the OGTT, appetite questionnaires using a visual analogue scale were administered, and blood was collected to measure ghrelin, peptide YY, glucose-dependent insulinotropic polypeptide, glucagon-like protein 1, leptin, and adiponectin. Mixed model analyses were conducted to examine between-group differences.

RESULTS

The children were similar in age, psychiatric diagnosis, and global assessment of functioning scores. Body mass index z-scores were also similar between groups. Appetite was increased during the OGTT in the risperidone-treated compared with the SGA-naive group for 2 questions ("How strong is your desire to eat"; P = 0.003 and "How much food do you think you can eat"; P = 0.028). No differences in satiety hormones were observed between the 3 groups.

CONCLUSIONS

Risperidone treatment in youth is associated with elevated appetite during an OGTT, with no differences in gut peptides or adipocytokines to explain risperidone's effect on appetite. Further research is needed to explore other mediators of weight gain and metabolic dysfunction in SGA-treated youth.

Metabolic side effects and pharmacogenetics of second-generation antipsychotics in children

Second-generation antipsychotics (SGAs) are increasingly being used to treat children for a range of mental health conditions, for example, anxiety disorder, attention deficit hyperactivity disorder and bipolar disorder. SGA treatment is associated with weight gain and cardiometabolic side effects such as dyslipidemia, insulin resistance and elevated blood pressure, in some, but not all children. This review provides an overview of the potential role of pharmacogenomics in predisposing a child to unhealthy weight gain and cardiometabolic side effects with SGA treatment. Specifically, the review includes a synopsis of the evidence for cardiometabolic side effects in SGA-treated children, illustrating the extent and depth of the problem; summarizes the potential long-term consequences of developing cardiometabolic risk during childhood and highlights genetic variants that may be useful in predicting cardiometabolic side effects in SGA-treated children.