Selective serotonin reuptake inhibitors affect neurobehavioral development in the human fetus

Fetal Behavior and Heart Rate in Twin Pregnancy: A Review

Fetal movements and fetal heart rate (FHR) are well-established markers of fetal well-being and maturation of the fetal central nervous system. The purpose of this paper is to review and discuss the available knowledge on fetal movements and heart rate patterns in twin pregnancies. There is some evidence for an association or similarity in fetal movement incidences or FHR patterns between both members of twin pairs. However, the temporal occurrence of these patterns seems to be for the most part asynchronous, especially when stricter criteria are used to define synchrony. The available data suggest that fetal behavior is largely independent of sex combination, fetal position, and presentation. Conversely, chorionicity appears to have some influence on fetal behavior, mainly before 30 weeks of gestation. There is preliminary evidence for the continuity of inter-individual differences in fetal activity and FHR patterns over pregnancy. Comparisons between studies are limited by large methodological differences and absence of uniform concepts and definitions. Future studies with high methodological quality are needed to provide a more comprehensive knowledge of normal fetal behavior in twin pregnancy.

Fetal serotonin reuptake inhibitor antidepressant exposure: maternal and fetal factors

Prenatal serotonin reuptake inhibitor exposure is common and neonatal outcomes vary greatly, often leading to confusion about whether to use or even continue antenatal use of these antidepressants. Importantly, some but not all infants are affected, which raises questions about how maternal drug metabolism contributes to fetal drug exposure. To address this key question, our paper reviews the role of key maternal, fetal, and placental pharmacokinetic, metabolic, and genetic factors that affect the extent of fetal drug exposure. Considering the role of these factors may further our understanding of variables that may assist in optimizing maternal psychopharmacotherapy during pregnancy and neonatal outcomes.

Fetal serotonin signaling: setting pathways for early childhood development and behavior

Finely tuning levels of the key neurotransmitter serotonin (5-hydroxytryptamine [5-HT]) during early life is essential for brain development and setting pathways for health and disorder across the early life span. Given the central role of 5-HT in brain development, regulation of mood, stress reactivity, and risk for psychiatric disorders, alterations in 5-HT signaling early in life have critical implications for behavior and mental health in childhood and adolescence. This article reviews the developmental consequences of two key influences that alter fetal 5-HT signaling: (1) in utero exposure to 5-HT reuptake inhibitor antidepressants, and (2) genetic variations in the 5-HT transporter gene (SLC6A4). The consequences of altered prenatal 5-HT signaling vary greatly, and developmental outcomes depend on an ongoing interplay between biological (genetic/epigenetic variations), experiential (prenatal drug or maternal mood exposure), and contextual (postnatal social environment) variables. Emerging evidence suggests both exposure to 5-HT reuptake inhibitors and genetic variations that affect 5-HT signaling may increase sensitivity to negative social contexts for some individuals, whereas for others, they may confer sensitivity to positive life circumstances. In this sense, factors that change central 5-HT levels may function less like influences that predict "vulnerability," but rather act like "plasticity factors." Understanding the impact of early changes in serotonergic programming offers critical insights that might explain patterns of individual differences in developmental risk and resilience.

Affect Expression and Self-Regulation Capacities of Infants Exposed in utero to Psychotropics

This study explored the affect expression and self-regulation capacities of 8-month-old infants exposed in utero to psychotropic medications. This was a continuation of our previous study conducted on the same cohort when the infants were 3 months old. Psychotropics implicated included selective serotonin reuptake inhibitors (SSRIs), and a benzodiazepine derivative anxiolytic (clonazepam). The three comparison groups were: control (n = 23; infants not exposed to psychotropics in utero), SSRI-alone (n = 22; infants exposed to SSRIs only and having mothers who had a primary diagnosis of depressive disorder without having comorbid anxiety disorder), and SSRI+ group (n = 15; infants gestationally exposed to SSRIs and clonazepam and having mothers that had both clinical depression and anxiety disorder). Using the Parent-Child Early Relational Assessment Scale, infants were assessed in a dyadic context during free play and a structured task. There were significant differences in psychotropic exposed and non-exposed dyads regarding infant negative affect management. There were significant associations between the SSRI+ group of mothers and infant negative affect. This group of mothers also showed significant associations with infants' averting and avoiding behaviors in both play situations. The SSRI-alone group was similar to the control group and showed variable associations with infant's positive, negative, and sober moods unlike the SSRI+ group. There were no differences in infants' capacity for self-regulation in psychotropic exposed and non-exposed groups. Increased awareness of these vulnerable subgroups (SSRI-alone and SSRI+) is needed, in order to safeguard these dyads through better support systems and improved management.

Dose-dependent effects of neonatal SSRI exposure on adult behavior in the rat

Neonatal exposure to antidepressants produces lasting impairments in male sexual behavior. Although perturbation of the serotonin system during neonatal life has been implicated in the long-term behavioral effects of neonatal antidepressant exposure, dose-response studies were necessary to confirm that inhibition of the serotonin transporter during the neonatal period is sufficient to produce impairments in sexual behavior. Therefore, the present study examined the dose-response effects of neonatal citalopram exposure on sexual behavior. In addition, the effects of exposure on anxiety-related behavior were examined since alterations in this behavioral measure could affect sexual behavior. Male Long-Evans rats were injected subcutaneously with citalopram (CTM) in one of three doses (5, 10 or 20mg/kg/d), or saline (SAL) in a volume of 0.1 ml twice daily (07:00 and 14:00 h) from PD8 to PD21. The rats were tested as adults (>PD90) for anxiety-like behavior and exploration in the elevated plus maze test and sexual behavior. Neonatal citalopram exposure produced persistent reductions in male sexual behavior characterized by significant dose-dependent reductions in the percentage of male rats displaying mounting as well as dose-dependent reductions in the number of mounts and mount latency. Neonatal citalopram exposure also produced significant dose-dependent linear trends for reductions in intromission and ejaculation behavior. However, neonatal SSRI exposure was not found to produce any effects on exploration or anxiety-like behavior in the elevated plus maze test. The present findings support the hypothesis that inhibition of the serotonin transporter during neonatal life by an SSRI is directly responsible for the long-term effects on male sexual behavior.

Selective serotonin reuptake inhibitors in human pregnancy: to treat or not to treat?

Selective serotonin reuptake inhibitors (SSRIs) are increasingly prescribed during pregnancy. The purpose of the present paper is to summarize and evaluate the current evidence for the risk/benefit analysis of SSRI use in human pregnancy. The literature has been inconsistent. Although most studies have not shown an increase in the overall risk of major malformations, several studies have suggested that SSRIs may be associated with a small increased risk for cardiovascular malformations. Others have noted associations between SSRIs and specific types of rare major malformations. In some studies, there appears to be a small increased risk for miscarriages, which may be associated with the underlying maternal condition. Neonatal effects have been described in up to 30% of neonates exposed to SSRIs late in pregnancy. Persistent pulmonary hypertension of the newborn has also been described with an absolute risk of <1%. The risk associated with treatment discontinuation, for example, higher frequency of relapse and increased risk of preterm delivery, should also be considered. The overall benefit of treatment seems to outweigh the potential risks.

Excess of serotonin affects neocortical pyramidal neuron migration

The serotonin transporter (SERT) is a key molecule involved in the homeostasis of extracellular levels of serotonin and is regulated developmentally. Genetic deletion of SERT in rodents increases extracellular levels of serotonin and affects cellular processes involved in neocortical circuit assembly such as barrel cortex wiring and cortical interneuron migration. Importantly, pharmacological blockade of SERT during brain development leads to phenotypes relevant to psychiatry in rodents and to an increased risk for autism spectrum disorders in humans. Furthermore, developmental adversity interacts with genetically-driven variations of serotonin function in humans and nonhuman primates to increase the risk for a variety of stress-related phenotypes. In this study, we investigate whether an excess of serotonin affects the migration of neocortical pyramidal neurons during development. Using in utero electroporation combined with time-lapse imaging to specifically monitor pyramidal neurons during late mouse embryogenesis, we show that an excess of serotonin reversibly affects the radial migration of pyramidal neurons. We further identify that the serotonin receptor 5-HT(6) is expressed in pyramidal neuron progenitors and that 5-HT(6) receptor activation replicates the effects of serotonin stimulation. Finally, we show that the positioning of superficial layer pyramidal neurons is altered in vivo in SERT knockout mice. Taken together, these results indicate that a developmental excess of serotonin decreases the migration speed of cortical pyramidal neurons, affecting a fundamental step in the assembly of neural circuits. These findings support the hypothesis that developmental dysregulation of serotonin homeostasis has detrimental effects on neocortical circuit formation and contributes to increased vulnerability to psychiatric disorders.