Variants of the serotonin transporter gene, selective serotonin reuptake inhibitors, and bone mineral density in risperidone-treated boys: a reanalysis of data from a cross-sectional study with emphasis on pharmacogenetics

Fluoxetine and Sertraline Inhibit Height Growth and Growth Hormone Signaling During Puberty

PURPOSE

The aim of this study was to examine the effect of fluoxetine and sertraline on height growth and insulin-like growth factor-1 (IGF-1) during puberty.

METHODS

In this 6-month cohort study, electronic medical records were used to identify 8- to 15-year-old participants, within 1 month of starting fluoxetine (n = 39) or sertraline (n = 27), and sexual maturation stages 2 to 4 were confirmed. Conditions that interfere with height growth led to exclusion. Participants underwent anthropometric assessments and phlebotomy. Healthy, unmedicated children (n = 36) also provided anthropometric data.

RESULTS

After the baseline height Z-score, sex, Tanner stage, daily selective serotonin reuptake inhibitor (SSRI) dose, and time were accounted for, the interaction effect of dose by time was inversely associated with height Z-score in SSRI-treated participants (β = -0.18; 95% confidence interval [CI]: -0.35, -0.02). Sertraline and fluoxetine did not differ in their effect on height growth. Compared with being unmedicated, SSRI treatment was associated with a smaller growth in height (time × dose 2-way interaction effect β = -1.30; 95% CI: -2.52, -0.09). The interaction effect of dose by time was significant for body mass index Z-score (β = 0.35; 95% CI: 0.06, 0.64) but not weight Z-score (β = 0.24; 95% CI: -0.01, 0.49). Body mass index Z-score increased more with sertraline compared with fluoxetine (time × dose × SSRI type 3-way interaction effect P < 0.05). SSRI dose was inversely associated with IGF-1 (β = -63.5; 95% CI: -112.2, -14.7) but not insulin growth factor binding protein-3 concentration (β = -207.3; 95% CI: -536.2, 121.5).

CONCLUSIONS

Fluoxetine and sertraline reduce height gain and IGF-1 concentration, in a dose-dependent manner. Longer-term studies are necessary.

Examining Whether Genetic Variants Moderate the Skeletal Effects of Selective Serotonin Reuptake Inhibitors in Older Adolescents and Young Adults

Objective: To examine whether serotonin (5-HT) related genetic variants moderate the effects of selective serotonin reuptake inhibitors (SSRIs) on skeletal outcomes. Methods: Trabecular bone mineral density (BMD) at the radius, lumbar spine (LS) BMD, total body less head (TBLH) bone mineral content (BMC) and markers of bone metabolism (osteocalcin, C-terminal telopeptide of type I collagen [CTX-1], and bone specific alkaline phosphatase to CTX-1 ratio) were examined in an observational study, enrolling 15- to 20-year-old participants, unmedicated or within a month of SSRI initiation. Variants in HTR1A (rs6295), HTR1B (rs6296), HTR1D (rs6300), HTR2A (rs6311 and rs6314), HTR2B (rs6736017), and the serotonin transporter intron 2 variable number tandem repeat (STin2 VNTR) were genotyped. Linear mixed-effects regression analysis examined associations between SSRI use, genetic variants, and skeletal outcomes. Results: After adjusting for relevant covariates, rs6295 CC and GC genotypes in 262 participants (60% female, mean ± SD age = 18.9 ± 1.6 years) were significantly associated with higher LS BMD compared to the GG genotype. Rs6311 GG SSRI users had greater LS BMD compared to nonusers (β = 0.18, p = <0.0001). Female SSRI users with the combination of rs6295 CC+GC and rs6311 GG genotypes had greater LS BMD than female SSRI nonusers (β = 0.29, p < 0.0001). SSRI users with the rs6295 GG genotype had higher trabecular BMD compared to nonusers (β = 3.60, p = 0.05). No significant interactions were found for TBLH BMC or bone turnover markers. After correcting for multiple comparisons, none of the results retained significance. Conclusions: In older adolescents and young adults, HTR1A (rs6295) and HTR2A (rs6311) variants may moderate the effect of SSRIs on BMD. Sex differences may exist and require further examination. Further research with larger sample sizes is needed to confirm our preliminary findings. Clinical Trial Registration: clinicaltrials.gov NCT02147184.

Review of the Long-Term Effect of the Atypical Antipsychotic Medication on the Bone Mineral Density of the Pediatric Patient with Consideration of Autism Spectrum Disorder

Objectives:

To shed some light on the understudied complication of chronic prolonged exposure to antipsychotics (AP) in children with consideration to with autism spectrum disorder (ASD).

Methods:

We electronically searched PubMed, Google Scholar, clinical trial.gov, and Medline Database of clinical studies up to June 2021. We used the following keywords: “bone mineral density, osteoporosis, osteopenia, bone loss, bone changes” AND “antipsychotics, SGAs, atypical antipsychotics” AND “pediatric, adolescent, young, youth, children.” We used [Mesh] Term for “antipsychotics agent” and “bone mineral density” and “autism spectrum disorder” and “child.” We retrieved relevant observational studies, reviews, case series, and randomized clinical trials.

Results:

Yvette Roke et al., in 2012, reported in a retrospective observational study that lumbar spine bone mineral density (BMD) and the biochemical bone marker were lower in the AP-treated boy with hyperprolactinemia in comparison to the non-AP-treated group, while a retrospective observational study of institutional adolescents with a psychiatric condition, carried out by Bonnot et al. in 2011, found significant vitamin D deficiency in psychiatric inpatient adolescents that is unrelated to the specific APs. Third, Calarge et al. in a 2010 retrospective observational study have reported a significant reduction in BMD in adolescents with risperidone-induced hyperprolactinemia and selective serotonin reuptake inhibitor (SSRI) compared to another group with risperidone-induced hyperprolactinemia without SSRI. On the other hand, Nivin A. Nagiub et al. (2019) in the cross-sectional study found no correlation between BMD and AP use in children with ASD. Houghton et al., in 2021, found a high fracture prevalence of 38% with aripiprazole compared to risperidone in children with ASD.

Conclusion:

Clinicians should be aware of the potential negative effects of APs on BMD, considerably in children with ASD that has additional risk factors for osteoporosis and bone disease. A provider needs to utilize more sensitive screening and diagnostic tools; the pediatric physician should evaluate other risk factors to prevent early osteopenia and bone fracture in children with ASD who are on chronic psychotropic medication, before adjusting to the AP medication.

Selective Serotonin Reuptake Inhibitors Reduce Longitudinal Growth in Risperidone-Treated Boys

OBJECTIVES

To examine whether selective serotonin reuptake inhibitors (SSRIs) inhibit longitudinal growth in children and adolescents, particularly in the early stages of puberty, using a sample of convenience comprising risperidone-treated boys.

STUDY DESIGN

Data from four clinic-based studies in risperidone-treated 5- to 17-year-old boys with no general medical conditions were combined for this analysis. Anthropometric measurements and psychotropic treatment history were extracted from the medical and pharmacy records. Linear mixed effects regression analyses examined the association between SSRI use and change in age-sex-specific height and body mass index z scores, after adjusting for relevant confounders.

RESULTS

Risperidone-treated boys (n = 267; age: 12.7 ± 2.7 years), 71% of whom had ever taken an SSRI, contributed to the analysis. After adjusting for age, psychostimulant and antipsychotic use, and time in the study, both the duration of SSRI use as well as the cumulative dose were inversely associated with height z score after age 11 years (P < .0001). After adjusting for baseline height, duration of SSRI use was most strongly inversely associated with height z score in Tanner stages 3 and 4 boys who took SSRIs continuously (r = -0.69, P < .009). No association was observed with body mass index z score.

CONCLUSIONS

In risperidone-treated boys, SSRI use is associated with reduced longitudinal growth, particularly in those undergoing puberty. Whether adult height or other metabolic or psychological outcomes are affected remains to be determined.

Association of the serotonin transporter-linked polymorphic region genotype with lower bone mineral density

The serotonin transporter-linked polymorphic region (5-HTTLPR) of the serotonin transporter gene (SLC6A4) S allele is linked to pathogenesis of depression and slower response to selective serotonin reuptake inhibitors (SSRIs); depression and SSRIs are independently associated with bone loss. We aimed to determine whether 5-HTTLPR was associated with bone loss. This cross-sectional study included psychiatric patients with both 5-HTTLPR analysis and bone mineral density (BMD) assessment (hip and spine Z-scores if age <50 years and T-scores if ⩾50 years). BMD association with 5-HTTLPR was evaluated under models with additive allele effects and dominant S allele effects using linear regression models. Patients were stratified by age (<50 and ⩾50 years) and sex. Of 3016 patients with 5-HTTLPR genotyping, 239 had BMD assessments. Among the younger patients, the S allele was associated with lower Z-scores at the hip (P=0.002, dominant S allele effects; P=0.004, additive allele effects) and spine (P=0.0006, dominant S allele effects; P=0.01, additive allele effects). In sex-stratified analyses, the association of the S allele with lower BMD in the younger patients was also significant in the subset of women (P⩽0.003 for both hip and spine BMD under the additive allele effect model). In the small group of men younger than 50 years, the S allele was marginally associated with higher spine BMD (P=0.05). BMD T-scores were not associated with 5-HTTLPR genotypes in patients 50 years or older. The 5-HTTLPR variants may modify serotonin effects on bone with sex-specific effects.

Bone growth in juvenile rhesus monkeys is influenced by 5HTTLPR polymorphisms and interactions between 5HTTLPR polymorphisms and fluoxetine

Male rhesus monkeys received a therapeutic oral dose of the selective serotonin reuptake inhibitor (SSRI) fluoxetine daily from 1 to 3 years of age. Puberty is typically initiated between 2 and 3 years of age in male rhesus and reproductive maturity is reached at 4 years. The study group was genotyped for polymorphisms in the monoamine oxidase A (MAOA) and serotonin transporter (SERT) genes that affect serotonin neurotransmission. Growth was assessed with morphometrics at 4 month intervals and radiographs of long bones were taken at 12 month intervals to evaluate skeletal growth and maturation. No effects of fluoxetine, or MAOA or SERT genotype were found for growth during the first year of the study. Linear growth began to slow during the second year of the study and serotonin reuptake transporter (SERT) long polymorphic region (5HTTLPR) polymorphism effects with drug interactions emerged. Monkeys with two SERT 5HTTLPR L alleles (LL, putative greater transcription) had 25-39% less long bone growth, depending on the bone, than monkeys with one S and one L allele (SL). More advanced skeletal maturity was also seen in the LL group, suggesting earlier onset of puberty. An interaction between 5HTTLPR polymorphisms and fluoxetine was identified for femur and tibia growth; the 5HTTLPR effect was seen in controls (40% less growth for LL) but not in the fluoxetine treated group (10% less growth for LL). A role for serotonin in peripubertal skeletal growth and maturation has not previously been investigated but may be relevant to treatment of children with SSRIs.

Longitudinal examination of the skeletal effects of selective serotonin reuptake inhibitors and risperidone in boys

OBJECTIVE

In a previous cross-sectional study, we found lower bone mass during treatment with selective serotonin reuptake inhibitors (SSRIs) and risperidone in youths. Here, we evaluate the skeletal effects of these psychotropics at follow-up.

METHOD

Between April 2005 and July 2011, medically healthy 7- to 17-year-old males treated with risperidone for 6 months or more were enrolled through child psychiatry outpatient clinics and returned for follow-up 1.5 years later. Treatment history was extracted from the medical and pharmacy records. Anthropometric, laboratory, and bone mass measurements were obtained. Multivariable linear regression analyses compared participants who remained on risperidone at follow-up to those who had discontinued risperidone treatment as well as SSRI-treated versus SSRI-unexposed participants.

RESULTS

The sample consisted of 94 boys with a mean age of 11.8 ± 2.7 years at study entry. The majority had an externalizing disorder and had received risperidone and SSRIs for 2.5 ± 1.7 years and 1.6 ± 1.9 years, respectively, at study entry. By follow-up, 26% (n = 24) had discontinued risperidone. Compared to discontinuing risperidone, continuing it was associated with a decline in participants' age-sex-height-race-specific areal bone mineral density (BMD) z score at the lumbar spine (P < .04) and failure to increase radius trabecular volumetric BMD (P < .03), after accounting for significant covariates. In addition, receiving an SSRI was associated with reduced lumbar spine areal BMD z score and radius trabecular volumetric BMD at both study entry (P < .02 and P < .03, respectively) and follow-up (P < .06 and P < .03, respectively), but without further decline between the 2 visits.

CONCLUSIONS

Chronic SSRI treatment in children and adolescents is associated with reduced, albeit stable, bone mass for age, while chronic risperidone treatment is associated with failure to accrue bone mass.

Major depressive disorder and bone mass in adolescents and young adults

Depression has been associated with reduced bone mass in adults, but the mechanisms remain unclear. In addition, little is known about the association between depression and bone health during growth and development. To address this knowledge gap, we examined bone density and structure in 222 adolescents and young adults (69% females, mean ± SD age: 19.0 ± 1.5 years), enrolled within 1 month of starting a selective serotonin reuptake inhibitor (SSRI) or unmedicated. Psychiatric functioning was assessed with self-report and researcher-administered instruments, including the Longitudinal Interval Follow-up Evaluation for Adolescents (A-LIFE). Anthropometric and laboratory measures included dual-energy x-ray absorptiometry and peripheral quantitative computed tomography scans. Linear multivariable regression analysis tested the association between depression and bone mass, after accounting for relevant confounders. The presence of current depression was associated with a significant reduction in age-sex-height-race-specific bone mineral density (BMD) and content (BMC) of total body less head and lumbar spine. The findings varied by assessment method with self-report scales, capturing symptom severity over the prior week or two, yielding the weakest associations. Depression was also associated with reduced cortical thickness and a trend for increased endosteal circumference. In contrast, generalized anxiety disorder was not associated with bone deficits. In sum, depressive illness is associated with significantly lower bone mass in youths. Future investigations must examine whether bone recovery is possible following depression remission or whether remedial interventions are warranted to optimize bone mass in order to minimize the long-term risk of osteoporosis.

Genetic variation in the serotonin transporter and HTR1B receptor predicts reduced bone formation during serotonin reuptake inhibitor treatment in older adults

OBJECTIVES

Studies have reported an association between serotonin reuptake inhibitors (SRIs) and accelerated bone loss. Genetic variation in the serotonin system might modulate bone metabolism changes during SRI treatment. In a clinical trial we examined functional genetic polymorphisms of serotonin transporter and receptors involved in bone metabolism to determine whether they predict changes in bone metabolism during SRI treatment.

METHODS

In 69 adults (age ≥ 60) participating in a 12-week, open-label trial of the SRI venlafaxine for major depression, serum markers of bone formation (P1NP) and resorption (β-CTX) were assayed before and after treatment. Participants were genotyped for putative high- versus low-expressing polymorphisms in the serotonin transporter (5HTTLPR) and 1B receptor (HTR1B) genes.

RESULTS

Bone formation was significantly reduced with administration of venlafaxine in participants with the high-expressing 5HTTLPR genotype and those with the low-expressing HTR1B genotype. This primarily occurred in individuals with the combination of the high-expressing 5HTTLPR genotype and the low-expressing HTR1B genotype.

CONCLUSIONS

These preliminary findings indicate that genetic variation in the serotonin receptors predicts changes in bone metabolism during SRI use. If these results are replicated and clinically confirmed, we will have identified a genetic subgroup at high risk for deleterious bone outcomes with the use of SRIs.

Possible mechanisms for the skeletal effects of antipsychotics in children and adolescents

The increasing use of antipsychotics (APs) to treat pediatric psychiatric conditions has led to concerns over the long-term tolerability of these drugs. While the risk of cardiometabolic abnormalities has received most of the attention, preclinical and clinical studies provide preliminary evidence that APs can adversely impact bone metabolism. This would be most concerning in children and adolescents as suboptimal bone accrual during development may lead to increased fracture risk later in life. However, the potential mechanisms of action through which APs may impact bone turnover and, consequently, bone mineral content are not clear. Emerging data suggest that the skeletal effects of APs are complex, with APs directly and indirectly impacting bone cells through modulation of multiple signaling pathways, including those involving dopamine D2, serotonin, adrenergic, and prolactin receptors, as well as by affecting gonadotropins. Determining the action of APs on skeletal development is further complicated by polypharmacy. In children and adolescents, APs are frequently coprescribed with psychostimulants and selective serotonin reuptake inhibitors, which have also been linked to changes in bone metabolism. This review discusses the mechanisms by which APs may influence bone metabolism. Also covered are preclinical and pediatric findings concerning the impact of APs on bone turnover. However, the dearth of clinical information despite the potential public health significance of this issue underscores the need for further studies. The review ends with a call for clinicians to be vigilant about promoting optimal overall health in chronically ill youth with psychopathology, particularly when pharmacotherapy is unavoidable.

Serotonin: a novel bone mass controller may have implications for alveolar bone

As recent studies highlight the importance of alternative mechanisms in the control of bone turnover, new therapeutic approaches can be envisaged for bone diseases and periodontitis-induced bone loss. Recently, it has been shown that Fluoxetine and Venlafaxine, serotonin re-uptake inhibitors commonly used as antidepressants, can positively or negatively affect bone loss in rat models of induced periodontitis. Serotonin is a neurotransmitter that can be found within specific nuclei of the central nervous system, but can also be produced in the gut and be sequestered inside platelet granules. Although it is known to be mainly involved in the control of mood, sleep, and intestinal physiology, recent evidence has pointed at far reaching effects on bone metabolism, as a mediator of the effects of Lrp5, a membrane receptor commonly associated with Wnt canonical signaling and osteoblast differentiation. Deletion of Lrp5 in mice lead to increased expression of Tryptophan Hydroxylase 1, the gut isoform of the enzyme required for serotonin synthesis, thus increasing serum levels of serotonin. Serotonin, in turn, could bind to HTR1B receptors on osteoblasts and stop their proliferation by activating PKA and CREB.

Although different groups have reported controversial results on the existence of an Lrp5-serotonin axis and the action of serotonin in bone remodeling, there is convincing evidence that serotonin modulators such as SSRIs can affect bone turnover. Consequently, the effects of this drug family on periodontal physiology should be thoroughly explored.

Pharmacogenomics of osteoporosis: a pathway approach

Osteoporosis is frequent in postmenopausal women and old men. As with other prevalent disorders, it is the consequence of complex interactions between genetic and acquired factors. Candidate gene and genome-wide association studies have pointed to several genes as determinants of the risk of osteoporosis. Some of them were previously unsuspected and may help to find new therapeutic targets. Several drugs already available are very effective in increasing bone mass and decreasing fracture risk. However, not all patients respond properly and some of them suffer fragility fractures despite therapy. Investigators have tried to identify the genetic features influencing the response to antiosteoporotic therapy. In this article we will review recent data providing insight into new genes involved in osteoporosis and the pharmacogenetic data currently available.

Brains, bones, and aging: psychotropic medications and bone health among older adults

Psychotropic drugs are a crucial element of treatment for psychiatric disorders; however there is an established association between many classes of psychotropic medications and fracture risk among older adults, and growing evidence that some classes of medications may also impact bone mineral density (BMD). In this paper we review recent epidemiologic research on the association between psychotropic medications and osteoporosis, and discuss current controversies and unresolved issues surrounding this relationship. Key areas in need of focused inquiry include resolving whether the apparent association between psychotropic medications and BMD is due to confounding by indication, whether this relationship differs for men and women, and whether the implications of these medications for bone health vary over the life course. Clinical research to delineate the risk/benefit ratio of psychotropic medications for older adults, particularly those who are at high risk for fracture, is also needed to facilitate prescribing decisions between patients and physicians.