Are typical starting doses of the selective serotonin reuptake inhibitors sub-optimal? A meta-analysis of randomized,double-blind,placebo-controlled,dose-finding studies in major depressive disorder

The purpose of this meta-analysis is to examine the relationship between selective serotonin reuptake inhibitor (SSRI) starting dose and treatment outcome in major depressive disorder (MDD). Medline/Pubmed, EMBASE, the Cochrane database, as well as a number of online clinical trial registries were searched for double-blind, placebo-controlled, fixed-dose trials comparing different starting doses of SSRIs for MDD. Data from nine trials (n=2340) were combined using a random-effects model. Patients randomized to receive the usual starting dose (10 mg escitalopram; 20 mg fluoxetine, paroxetine, citalopram; 50 mg sertraline and fluvoxamine) were less likely to respond than patients who received higher starting doses (RR=0.9; P=0.04; response rate 50.8 vs. 54.8%). The rate of discontinuation due to adverse events was lower among the usual starting dose group (9.8%) compared to the higher starting dose group (16.5%).Initiating treatment with SSRIs at doses higher than those typically used in clinical trials/settings is associated with higher response rates but also higher rates of discontinuation due to intolerance. Developing treatment strategies allowing clinicians to deliver higher initial SSRI doses while enhancing the tolerability of treatment may represent an alternative approach to improving the efficacy of treatment of MDD.     

Developmental effects of SSRIs: lessons learned from animal studies.

Selective serotonin reuptake inhibitors (SSRIs) are utilized in the treatment of depression in pregnant and lactating women. SSRIs may be passed to the fetus through the placenta and the neonate through breastfeeding, potentially exposing them to SSRIs during peri- and postnatal development. However, the long-term effects of this SSRI exposure are still largely unknown. The simplicity and genetic amenability of model organisms provides a critical experimental advantage compared to studies with humans. This review will assess the current research done in animals that sheds light on the role of serotonin during development and the possible effects of SSRIs. Experimental studies in rodents show that administration of SSRIs during a key developmental window creates changes in brain circuitry and maladaptive behaviors that persist into adulthood. Similar changes result from the inhibition of the serotonin transporter or monoamine oxidase, implicating these two regulators of serotonin signaling in developmental changes. Understanding the role of serotonin in brain development is critical to identifying the possible effects of SSRI exposure.     

Serotonin transporter occupancy of five selective serotonin reuptake inhibitors at different doses: an [11C]DASB positron emission tomography study

OBJECTIVE: Minimum therapeutic doses of paroxetine and citalopram produce 80% occupancy for the serotonin (5-HT) transporter (5-HTT). The authors used [(11)C]DASB positron emission tomography to measure occupancies of three other selective serotonin reuptake inhibitors (SSRIs) at minimum therapeutic doses. The relationship between dose and occupancy was also investigated. METHOD: Striatal 5-HTT binding potential was measured in 77 subjects before and after 4 weeks of medication administration. Binding potential is proportional to the density of receptors not blocked by medication. Subjects received citalopram, fluoxetine, sertraline, paroxetine, or extended-release venlafaxine. Healthy subjects received subtherapeutic doses; subjects with mood and anxiety disorders received therapeutic doses. Percent reduction in 5-HTT binding potential for each medication and dose was calculated. To obtain test-retest data, binding potential was measured before and after 4 weeks in six additional healthy subjects. RESULTS: Substantial occupancy occurred at subtherapeutic doses for all SSRIs. Compared to test-retest data, each drug at the minimum therapeutic dose had a significant effect on striatal 5-HTT binding potential. Mean occupancy at this dose was 76%-85%. At higher plasma SSRI concentrations, 5-HTT occupancy tended to increase above 80%. For each drug, as the dose (or plasma level) increased, occupancy increased nonlinearly, with a plateau for higher doses. CONCLUSIONS: At tolerable doses, SSRIs have increasing occupancy with increasing plasma concentration or dose. Occupancy of 80% across five SSRIs occurs at minimum therapeutic doses. This suggests that 80% 5-HTT blockade is important for therapeutic effect. Occupancy should be measured during development of antidepressant compounds targeting the 5-HTT.     

A meta-analysis of clinical trials comparing the serotonin (5HT)-2 receptor antagonists trazodone and nefazodone with selective serotonin reuptake inhibitors for the treatment of major depressive disorder.

OBJECTIVE: To compare response rates among patients with major depressive disorder (MDD) treated with either a serotonin-2 (5HT2-) receptor antagonist or a selective serotonin reuptake inhibitor (SSRI). METHODS: Medline and PubMed were searched for double-blind, randomized clinical trials comparing either trazodone or nefazodone with an SSRI for the treatment of MDD. Data from 9 reports involving a total 988 patients were identified and combined using a random-effects model. RESULTS: Patients randomized to treatment with a 5HT2 antagonist were as likely to experience clinical response as patients randomized to treatment with an SSRI (RR=1.002, 95% CI: 0.85-1.17, P=0.978). Pooled response rates for trazodone/nefazodone and the SSRIs were 61.1% and 61.7%, respectively. There was also no difference in overall discontinuation rates (P=0.334), discontinuation due to adverse events (P=0.676), or discontinuation due to inefficacy (P=0.289) between the two groups. CONCLUSIONS: These results suggest that the 5HT2-receptor antagonists trazodone and nefazodone and the SSRIs do not differ with respect to their overall efficacy and tolerability in the treatment of MDD. Although the sample size was relatively large and conveyed sufficient statistical power to test for differences in the overall sample, depression is a heterogeneous condition and differences may exist between treatments in particular subgroups of patients.     

A metaanalysis of clinical trials comparing moclobemide with selective serotonin reuptake inhibitors for the treatment of major depressive disorder.

OBJECTIVE: To compare response rates among patients with major depressive disorder (MDD) treated with either moclobemide, an antidepressant thought to simultaneously enhance both noradrenergic and serotonergic neurotransmission, or selective serotonin reuptake inhibitors (SSRIs). METHODS: Using a random-effects model, we combined 12 trials involving 1207 outpatients with MDD. RESULTS: Patients treated with moclobemide were as likely to experience clinical response as those treated with SSRIs (risk ratio 1.08; 95% confidence interval, 0.92 to 1.26; P = 0.314). Simply pooling response rates for the 2 agents resulted in a 62.1% response rate for moclobemide and a 57.5% response rate for the SSRIs. A metaregression did not reveal a statistically significant relation between the mean moclobemide dosage for each study and the risk ratio for response rates. Further, we found no difference between the 2 treatments in overall discontinuation rates, discontinuation rates due to adverse events, or discontinuation rates due to lack of efficacy. Also, rates of fatigue or somnolence and of insomnia were similar between the 2 treatment groups. However, SSRI treatment was associated with higher rates of nausea, headaches, and treatment-emergent anxiety than was treatment with moclobemide. CONCLUSIONS: These results suggest that moclobemide and the SSRIs do differ with respect to their side effect profiles but not in their overall efficacy in the treatment of MDD.     

Low-dose escitalopram for 2 days associated with corrected QT interval prolongation in a middle-aged woman: a case report and literature review

Prolongation of the corrected QT interval (QTc) on the electrocardiography is an important clinical condition because it increases the risk of torsade de pointes, a medical emergency that can cause sudden cardiac death. QTc prolongation can be induced by many drugs, including antipsychotics and tricyclic antidepressants (TCAs). Compared with TCAs, use of selective serotonin reuptake inhibitors (SSRIs) was less likely to cause severe cardiac adverse effects. Escitalopram, one of the SSRIs, has shown significant antidepressant efficacy and well tolerability. Here, we present one female patient showing QTc prolongation induced by low-dose (5 mg/day) treatment of escitalopram for 2 days. The QTc returned to normal soon after discontinuation of escitalopram. Clinicians should be cautious about cardiac effects when using a SSRI, even in a low dose.     

Antidepressants and suicidal behaviour in unipolar depression

OBJECTIVE: To compare the rates of suicidal behaviour during vs. after discontinuation of treatment with antidepressants, and to determine the comparative rates of suicidal behaviour for patients maintained on tricyclic (TCA) vs. selective serotonin reuptake inhibitor (SSRI) antidepressants. METHOD: Charts were reviewed for 521 patients with major depressive disorder and/or dysthymic disorder. Periods of active treatment or discontinuation with SSRIs or TCAs were determined. Rates of completed suicide, suicide attempts, and hospitalization for suicidality were analyzed. RESULTS: There was greater than a five-fold increase in risk for suicidal behaviour after discontinuation of antidepressant treatment (P < 0.0001). The rates of suicidal behavior during treatment with SSRIs or TCAs were similar. CONCLUSION: Suicidal behaviour in unipolar depressed patients treated with antidepressants increases substantially after medication discontinuation. This effect occurred in both patients who were maintained on SSRIs and TCAs. The findings support a possible protective effect on suicidal behaviour for both SSRIs and TCAs.     

The effects of maternal antidepressant use on offspring behaviour and brain development: Implications for risk of neurodevelopmental disorders

Approximately 10% of pregnant women are prescribed antidepressant drugs (ADDs), with selective serotonin reuptake inhibitors (SSRIs) the most widely prescribed. SSRIs bind to the serotonin transporter (SERT), blocking the reabsorption of serotonin by the presynaptic neuron and increasing serotonin levels in the synaptic cleft. The serotonergic system regulates a range of brain development processes including neuronal proliferation, migration, differentiation and synaptogenesis. Given the presence of SERT in early brain development, coupled with the ability of SSRIs to cross the placenta and also enter breast milk, concerns have been raised regarding the effects of SSRI exposure on the developing foetus and newborns. In this review, we evaluate preclinical and clinical studies that have examined the effects of maternal SSRI exposure and the risk for altered neurodevelopment and associated behaviours in offspring. While the current body of evidence suggests that maternal SSRI treatment may cause perturbations to the neurobiology, behaviour and ultimately risk for neurodevelopmental disorders in exposed offspring, conflicting findings do exist and the evidence is not conclusive. However, given the increasing incidence of depression and number of women prescribed ADDs during pregnancy, further investigation into this area is warranted.     

How have the selective serotonin reuptake inhibitor antidepressants affected suicide mortality?

OBJECTIVE: We review evidence on two claims that have been made about the effects of selective serotonin reuptake inhibitor (SSRI) antidepressants; that they have: (i) decreased suicide rates in the population; and (ii) increased suicide rates in some individuals early in treatment. METHOD: We critically review evidence in the English-speaking peer-reviewed medical literature on: (i) meta-analyses of randomized controlled trials (RCTs) of SSRIs; (ii) observational studies of suicide risk in patients prescribed SSRIs and other antidepressants; and (iii) ecological studies of correlations between population use of SSRI use and population suicide rates. RESULTS: The largest and most recent meta-analyses of RCTs of SSRIs have found suggestive evidence that SSRIs increase suicidal ideation early in treatment compared with placebo. Observational studies have found an increased risk of self-harm within 9 days of an antidepressant drug being prescribed but the risk has been similar for the older tricyclic antidepressants and the SSRIs. Ecological studies in developed countries have found either that suicide rates have declined as SSRI use has increased, or have found no relationship between suicide rates and increased SSRI use. CONCLUSIONS: Meta-analyses of RCTs suggest that SSRIs increase suicide ideation compared with placebo but the observational studies suggest that SSRIs do not increase suicide risk more than older antidepressants. If SSRIs increase suicide risk in some patients, the number of additional deaths is very small because ecological studies have generally found that suicide mortality has declined (or at least not increased) as SSRI use has increased.     

Dose-response relationship of recent antidepressants in the short-term treatment of depression

Antidepressant drugs are widely recommended for the treatment of depressive disorders, and finding the "right dose for the right patient" is an important issue. Whatever antidepressant is prescribed, a proportion of adult patients with major depression fail to respond satisfactorily to adequate first-line treatment. A frequent strategy for patients with insufficient response to an initial antidepressant dose is to increase the dose. This review is about this strategy, ie, the possible benefits of prescribing higher doses of recent antidepressants. The results show that a flat dose-response curve is a class phenomenon for selective serotonin reuptake inhibitors (SSRIs), according to randomized, controlled, fixed-dose clinical trials. For the serotonin and noradrenaline reuptake inhibitors (SNRIs), the strategy of dose increase may be relevant for venlafaxine, in order to increase the number of responders. Thus, the subgroup of patients for whom high doses of SSRIs could be useful remains to be defined.     

Nine-month predictors and outcomes of SSRI antidepressant continuation in primary care

BACKGROUND: This study aimed to identify the predictors and outcomes of SSRI antidepressant continuation, discontinuation and switching over a 9-month period of naturalistic observation. METHODS: Primary care patients (n=573) with physician-diagnosed depression from 37 practices were randomized to an open-label trial of one of three selective serotonin reuptake inhibitors (SSRIs) managed in their primary care setting. Psychiatric characteristics and treatment course were assessed at baseline and at 1, 3, 6 and 9 months after medication initiation. RESULTS: Nineteen percent of patients switched SSRIs, which occurred significantly sooner than discontinuation (median: 41 vs.100 days). Time to discontinuation was primarily explained by baseline patient skepticism about taking an antidepressant (62% increase in discontinuation risk). In contrast, time to switch was associated with greater impairment at baseline and lesser improvement in impairment during the first month on medication. Patients who discontinued were significantly less likely to be depressed 9 months after starting medication than those who either continued or switched medication, and were less symptomatic and impaired than patients who switched. CONCLUSIONS: Baseline impairment may increase the risk for SSRI antidepressant switching. Additionally, patient skepticism about antidepressants predicts early SSRI discontinuation and may predict rapid recovery. Intent-to-treat analyses in nonrandomized clinical trials may paradoxically inflate antidepressant effect sizes.     

Evidence that the SSRI dose response in treating major depression should be reassessed: a meta-analysis

The limitations in design and analysis of currently available dose-response studies of SSRI treatment of major depression have led to the conclusion that dose response is flat. We applied concepts from our companion article to determine if currently available data is consistent with a "potential" and an "expressed" dose response. Using these concepts, we performed a meta-analysis on all identifiable published fixed-dose and dose-escalation studies that reported the effect of different SSRI oral doses on efficacy. "Potential" dose response in fixed-dose studies with categorical response outcomes equaled a significant meta-analyzed slope of 3.1%/100 SSRI mg equivalents (SMEs) (SE=1.2%) or 7.8% across the dose range. Similar analysis in dose-escalation studies that reported categorical response data yielded a non-significant meta-analyzed slope of 3.7%/100 SMEs (SE=2.3%) or 9.3% across the dose range. Analyses of the "expressed" dose response demonstrated in the studies indicated a slope statistically equal to zero. The current analysis suggests a "potential" dose response can be demonstrated for SSRIs in treating major depression. The analysis suggests an "expressed" dose response could exist in best clinical practice. Study designs better tailored to address the relevant clinical question would test these hypotheses more appropriately than previous studies.     

Treatment-emergent adverse events from selective serotonin reuptake inhibitors by age group: children versus adolescents

OBJECTIVE: The aim of this study was to report the frequency of common treatment-emergent adverse events (AEs) from selective serotonin reuptake inhibitors (SSRIs) in children, adolescents, and adults. METHOD: AE data were obtained from all published double-blind, placebo-controlled SSRI studies of children and adolescents that separated AE findings by age group. The AE findings were pooled for purposes of age-group comparisons. Double-blind, placebo-controlled SSRI studies of adolescents (n = 2) and of adults identified in systematically identified trials (n = 22) were assessed to compare patterns and rates across the age span. Other reports, primarily from the published SSRI literature, were added to clarify the findings presented. RESULTS: Activation and vomiting SSRI AEs were 2- to 3-fold more prevalent in children than in adolescents, and their rate was lowest in adults. Somnolence as a SSRI AE was uncommon in children; its rate increased with advancing age. Insomnia and nausea were common SSRI AEs across the age span. Activation AEs were a frequent reason for discontinuation from SSRI clinical trials in preadolescents, whereas somnolence, nausea, and insomnia AEs were the most common reasons for trial discontinuations in adults. CONCLUSIONS: Children are particularly vulnerable to specific AEs from certain medications, such as SSRIs. It is likely that the level of children's biological immaturity explains part of this phenomenon.     

Inflammation-Induced Histamine Impairs the Capacity of Escitalopram to Increase Hippocampal Extracellular Serotonin

Commonly prescribed selective serotonin reuptake inhibitors (SSRIs) inhibit the serotonin transporter to correct a presumed deficit in extracellular serotonin signaling during depression. These agents bring clinical relief to many who take them; however, a significant and growing number of individuals are resistant to SSRIs. There is emerging evidence that inflammation plays a significant role in the clinical variability of SSRIs, though how SSRIs and inflammation intersect with synaptic serotonin modulation remains unknown. In this work, we use fast in vivo serotonin measurement tools to investigate the nexus between serotonin, inflammation, and SSRIs. Upon acute systemic lipopolysaccharide (LPS) administration in male and female mice, we find robust decreases in extracellular serotonin in the mouse hippocampus. We show that these decreased serotonin levels are supported by increased histamine activity (because of inflammation), acting on inhibitory histamine H3 heteroreceptors on serotonin terminals. Importantly, under LPS-induced histamine increase, the ability of escitalopram to augment extracellular serotonin is impaired because of an off-target action of escitalopram to inhibit histamine reuptake. Finally, we show that a functional decrease in histamine synthesis boosts the ability of escitalopram to increase extracellular serotonin levels following LPS. This work reveals a profound effect of inflammation on brain chemistry, specifically the rapidity of inflammation-induced decreased extracellular serotonin, and points the spotlight at a potentially critical player in the pathology of depression, histamine. The serotonin/histamine homeostasis thus, may be a crucial new avenue in improving serotonin-based treatments for depression.SIGNIFICANCE STATEMENT Acute LPS-induced inflammation (1) increases CNS histamine, (2) decreases CNS serotonin (via inhibitory histamine receptors), and (3) prevents a selective serotonin reuptake inhibitor (SSRI) from effectively increasing extracellular serotonin. A targeted depletion of histamine recovers SSRI-induced increases in extracellular hippocampal serotonin.     

Naturalistic study of the early psychiatric use of citalopram in the United States

We obtained information on the efficacy and safety of citalopram in settings that resemble actual clinical practice. A total of 1,783 patients participated in this open, uncontrolled, naturalistic Phase IV evaluation of citalopram at 447 U.S. investigative sites. Participants were selected by guidelines in the citalopram package insert using minimal exclusion criteria. Citalopram dosing began at 20 mg/day and could be titrated to 60 mg/day. Outcomes included the Clinical Global Impressions-Improvement scale (CGI-I) and a Patient Global Evaluation. Separate analyses were performed on patients with a primary diagnosis of major depressive disorder (MDD) (76%) who reported intolerance or nonresponse to previous selective serotonin reuptake inhibitors (SSRIs). Patients included tended to have treatment-resistant or intolerant, chronic or recurrent, comorbid depression with a mean duration of illness of 10 years. At study completion, more than 68% of treatment completers were classified as responders (CGI-I score of 1 or 2). Endpoint analyses showed response rates of 54% in all patients, 56% in patients with MDD, 49% in SSRI nonresponsive patients, and 53% in patients with a history of SSRI intolerance. Nausea (9.8%) and headache (7.3%) were the most often reported adverse events. Patients with a history of SSRI intolerance had a discontinuation rate of 21.8%, whereas those without such a history had a discontinuation rate of 13.3%. Citalopram administered at an average dose of 23.6 mg/day was associated with favorable outcomes and was generally well tolerated.     

Peripheral and central neurochemical effects of the selective serotonin reuptake inhibitors (SSRIs) in humans and nonhuman primates: assessing bioeffect and mechanisms of action

It is clear that selective serotonin reuptake inhibitors (SSRIs) act powerfully to inhibit serotonin (5-hydroxytryptamine, 5-HT) uptake centrally and peripherally. However, there are a number of critical unanswered questions concerning the effects of the drugs in adults and children. The influence of age and duration of treatment on the extent of uptake inhibition and on the enhancement of central serotonergic functioning are unclear. In addition, the relationship of these factors and effects to the therapeutic and adverse effects of the SSRIs remain to be clarified. The general clinical utility of platelet 5-HT measurement is reviewed and studies assessing central and peripheral uptake blockade in infants and children and non-human primates are discussed. Recent investigations of central neurochemical effects of the SSRIs in primates assessed through measurement of 5-HT and related compounds in cisternal cerebrospinal fluid (CSF) of the rhesus monkey are presented. In summary, the studies described have found that: human fetal exposure to SSRIs has substantial effects on 5-HT transport in utero; exposure to SSRIs through breastmilk of mothers treated for postpartum depression usually has negligible effects on 5-HT uptake; prescribed SSRIs appear to exert similar effects on 5-HT transporter blockade in children and adults; and rapid and sustained increases are seen in monkey cisternal CSF levels of 5-HT upon initiation of SSRI administration. The implications of the observations in terms of behavioral effects, clinical practice, and underlying mechanisms of action of the SSRIs are discussed.     

Candidate genes for antidepressant response to selective serotonin reuptake inhibitors

Selective serotonin reuptake inhibitors (SSRIs) can safely and successfully treat major depression, although a substantial number of patients benefit only partially or not at all from treatment. Genetic polymorphisms may play a major role in determining the response to SSRI treatment. Nonetheless, it is likely that efficacy is determined by multiple genes, with individual genetic polymorphisms having a limited effect size. Initial studies have identified the promoter polymorphism in the gene coding for the serotonin reuptake transporter as moderating efficacy for several SSRIs. The goal of this review is to suggest additional plausible polymorphisms that may be involved in antidepressant efficacy. These include genes affecting intracellular transductional cascades; neuronal growth factors; stress-related hormones, such as corticotropin-releasing hormone and glucocorticoid receptors; ion channels and synaptic efficacy; and adaptations of monoaminergic pathways. Association analyses to examine these candidate genes may facilitate identification of patients for targeted alternative therapies. Determining which genes are involved may also assist in identifying future, novel treatments.     

Value of fluoxetine in obsessive-compulsive disorder in the adult: review of the literature

Fluoxetine is a selective serotonin reuptake inhibitor (SSRI) with demonstrated efficacy in the treatment of major depressive episodes. Since 1985, it has been evaluated for the treatment of obsessive-compulsive disorder (OCD). The orbitofrontal cortex and caudate nucleus are cerebral structures believed to be involved in the pathogenesis of OCD, since hyperactivation of these territories in the basal state is corrected upon remission of symptoms induced by therapy with an SSRI or by behavioral psychotherapy. Furthermore, several studies have found abnormalities in serotoninergic transmission in the orbitofrontal cortex and SSRIs can increase serotonin release by desensitizing 5HTID autoreceptors. OCD is a severe, chronic psychiatric disorder frequently complicated by depressive episodes. Here we review the clinical trials of fluoxetine listed in the Medline and Embase computerized databases. Fluoxetine was found to be effective in OCD in all the published open-label studies as well as in placebo-controlled trials with an effective dose range of 40 to 60 mg daily. Clinical evaluation was carried out by using specific scales such as the Y-BOCS or NIMH-OC and improvement was observed after several weeks of therapy. These studies comprising an extended phase showed that efficacy was maintained--for three years in the longest study--resulting in a higher percentage of responders relative to the treatment initiation phase. A comparison of fluoxetine and clomipramine showed comparable efficacy and a superior safety profile, both in terms of anticholinergic side effects and cardiotoxicity or overdosage. The relapse rate was similar with both drugs. In the four meta-analyses appearing in the databases, two studies found similar efficacy for clomipramine and fluoxetine. There are few studies which directly compare the different SSRIs, apart from a comparison of fluoxetine and sertraline showing that both drugs have similar efficacy. With clomipramine, the SSRIs represent the first-line treatment recommended by the experts, in association with behavioral therapy to improve and maintain the clinical response over the long term. The guidelines recommend an optimal fluoxetine dose of 40 to 60 mg daily with a minimum treatment duration of 1 to 2 years. Efficacy should not be evaluated before 8 weeks to allow for onset of the therapeutic effects. Fluoxetine was found to have a good safety profile in these studies and the adverse effects described (insomnia, headache, diminished libido) rarely led to discontinuation of the treatment. Adverse effects such as nervousness or insomnia at the start of therapy were predictors of a good response to fluoxetine, as were the presence of remissions, the absence of prior pharmacologic therapy and a high impulsiveness score. A long history of the disorder, severity of the symptoms, collection obsessions, washing compulsions, obsessional slowness and comorbidity with a schizotypic personality or vocal or motor tics were associated with a poorer response. Fluoxetine also alleviates collateral depressive symptoms by significantly reducing suicidal ideation and impulsiveness in OCD patients. Our study indicates that fluoxetine is effective and well tolerated in OCD, placing it among the first-line treatments recommended by consensus conference guidelines.     

Selective serotonin reuptake inhibitors for children and adolescents

The controlled studies of selective serotonin reuptake inhibitors (SSRIs) in pediatric psychopharmacology research lag behind the controlled studies of SSRIs in adults. As a result, widespread use of SSRIs in the treatment of child and adolescent psychiatric disorders is in stark contrast to the paucity of research data. Recent changes in the research climate (including support from the National Institute of Mental Health, the Food and Drug Administration, and industry) have encouraged welldesigned SSRI studies in pediatric psychopharmacology, and will ultimately provide needed information to guide treatment. This paper reviews the best available data from pediatric SSRI trials, including 10 double-blind placebo-controlled trials, and two abstracts of open-label continuation studies of SSRIs associated with large pediatric efficacy studies. Adverse events (AEs) of SSRIs in children and adolescents are discussed in reference to available pediatric studies. Recent pharmacokinetic studies of SSRIs in children and adolescents are reviewed. Future SSRI research strategies are also discussed.     

Platelet serotonin reuptake inhibition and response to SSRIs in depressed adolescents

OBJECTIVE: The authors examined platelet serotonin reuptake inhibition and response to selective serotonin reuptake inhibitor (SSRI) treatment in depressed adolescents. METHOD: Twenty-three depressed adolescents participating in pharmacokinetic studies of SSRIs had platelet serotonin reuptake measured before and after 14-28 days of treatment. The Clinical Global Impression (CGI) improvement rating was determined on the basis of all clinical information and was performed blind to the platelet data. RESULTS: Improvement in depressive symptoms as rated with the CGI improvement subscale was significantly associated with the percentage change in platelet serotonin reuptake inhibition from pre- to posttreatment. Improvement in depression was also associated with absolute decrease in platelet serotonin reuptake when adjusted for the magnitude of baseline reuptake. CONCLUSIONS: Platelet serotonin reuptake inhibition may be an appropriate surrogate biological marker for the pharmacodynamic activity of SSRIs in depressed adolescents.