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Journal ArticleDOI

Role of selective serotonin reuptake inhibitors in psychiatric disorders: a comprehensive review.

TL;DR: Although no clear relationship exists between the clinical efficacy, plasma concentration of SSRIs, nor any threshold that defines toxic concentrations, therapeutic drug monitoring (TDM) may be useful in special populations, such as in elderly patients, poor metabolizers (PM) of sparteine or mephenytoin (CYP2C19), and patients with liver and kidney impairment.
Abstract: The selective serotonin reuptake inhibitors (SSRIs) have emerged as a major therapeutic advance in psychopharmacology. As a result, the discovery of these agents marks a milestone in neuropsychopharmacology and rational drug design, and has launched a new era in psychotropic drug development. Prior to the SSRIs, all psychotropic medications were the result of chance observation. In an attempt to develop a SSRI, researchers discovered a number of nontricyclic agents with amine-uptake inhibitory properties, acting on both noradrenergic and serotonergic neurons with considerable differences in potency. A given drug may affect one or more sites over its clinically relevant dosing range and may produce multiple and different clinical effects. The enhanced safety profile includes a reduced likelihood of pharmacodynamically mediated adverse drug-drug interactions by avoiding affects on sites that are not essential to the intended outcome. SSRIs were developed for inhibition of the neuronal uptake pump for serotonin (5-HT), a property shared with the TCAs, but without affecting the other various neuroreceptors or fast sodium channels. The therapeutic mechanism of action of SSRIs involves alteration in the 5-HT system. The plethora of biological substrates, receptors and pathways for 5-HT are candidates to mediate not only the therapeutic actions of SSRIs, but also their side effects. A hypothesis to explain these immediate side effects is that 5-HT is increased at specific 5-HT receptor subtypes in discrete regions of the body where the relevant physiologic processes are regulated. Marked differences exist between the SSRIs with regard to effects on specific cytochrome P450 (CYP) enzymes, and thus the likelihood of clinically important pharmacokinetic drug-drug interactions. Although no clear relationship exists between the clinical efficacy, plasma concentration of SSRIs, nor any threshold that defines toxic concentrations, but therapeutic drug monitoring (TDM) may be useful in special populations, such as in elderly patients, poor metabolizers (PM) of sparteine (CYP2D6) or mephenytoin (CYP2C19), and patients with liver and kidney impairment. Several meta-analyses have reviewed the comparative efficacy of TCAs and SSRIs, and concluded that both TCAs and SSRIs have similar efficacy in the treatment of depression. SSRIs have demonstrated better efficacy and tolerability in the treatment of obsessive compulsive disorder (OCD). They have also been found to be effective in the treatment for social anxiety disorder both in reducing total levels of social anxiety and in improving overall clinical condition. The benefit of SSRIs in anorexia nervosa (AN) is apparently short-term unless medication is given in the context of nutritional or behavioral therapy. No single antidepressant can ever be recommended for every patient, but in a vast majority of patients, SSRIs should be considered as one of the first-line drugs in the treatment of depression.
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TL;DR: It is suggested that a refined definition of anhedonia that distinguishes between deficits in pleasure and motivation is essential for the purposes of identifying its neurobiological substrates and introduced the term "decisionalAnhedonia" to address the influence of anhydonia on reward decision-making.

1,166 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present a review of the use of the EPM as a post-hoc test to evaluate emotionality in genetically modified rodents and identify and control of major sources of variability in this test.

894 citations


Cites background from "Role of selective serotonin reuptak..."

  • ...…reuptake inhibitors (SSRIs), is effective in anxiety disorders (Argyropoulos et al., 2000; Millan, 2003; Vaswani et al., 2003) has stimulated researchers to develop anxiolytics that influence the serotonin and/or noradrenergic systems (Kent et al., 2002; Gorman, 2003; Vaswani et al., 2003)....

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  • ...Moreover, the recognition that chronic treatment with antidepressants, such as the selective serotonin reuptake inhibitors (SSRIs), is effective in anxiety disorders (Argyropoulos et al., 2000; Millan, 2003; Vaswani et al., 2003) has stimulated researchers to develop anxiolytics that influence the serotonin and/or noradrenergic systems (Kent et al....

    [...]

  • ...…such as the selective serotonin reuptake inhibitors (SSRIs), is effective in anxiety disorders (Argyropoulos et al., 2000; Millan, 2003; Vaswani et al., 2003) has stimulated researchers to develop anxiolytics that influence the serotonin and/or noradrenergic systems (Kent et al., 2002;…...

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  • ..., 2003) has stimulated researchers to develop anxiolytics that influence the serotonin and/or noradrenergic systems (Kent et al., 2002; Gorman, 2003; Vaswani et al., 2003)....

    [...]

Journal ArticleDOI
TL;DR: This review explores the idea that specific gene polymorphisms and neurotransmitter systems can confer protection from or vulnerability to specific symptom dimensions of cytokine-related depression and potential therapeutic strategies that target inflammatory cytokine signaling.

771 citations

Journal ArticleDOI
TL;DR: The attenuation of pro-inflammatory immune responses, and the elevation of the serotonergic precursor, tryptophan by bifidobacteria treatment, provides encouraging evidence in support of the proposition that this probiotic may possess antidepressant properties.

743 citations


Cites background from "Role of selective serotonin reuptak..."

  • ...The side-effect profiles of these earlier treatments have significantly improved with the introduction of the selective serotonin re-uptake inhibitors (Vaswani et al., 2003), and the more recent emergence of the serotonin and noradrenaline re-uptake inhibitors (Papakostas et al., 2007)....

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  • ...The side-effect profiles of these earlier treatments have significantly improved with the introduction of the selective serotonin re-uptake inhibitors (Vaswani et al., 2003), and the more recent emergence of the serotonin and noradrenaline re-uptake inhibitors (Papakostas et al....

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Journal ArticleDOI
TL;DR: These studies indicate that metabotropic glutamate receptors are interesting new targets to treat anxiety disorders in humans.
Abstract: Anxiety and stress disorders are the most commonly occurring of all mental illnesses, and current treatments are less than satisfactory. So, the discovery of novel approaches to treat anxiety disorders remains an important area of neuroscience research. Glutamate is the major excitatory neurotransmitter in the mammalian central nervous system, and G-protein-coupled metabotropic glutamate (mGlu) receptors function to regulate excitability via pre- and postsynaptic mechanisms. Various mGlu receptor subtypes, including group I (mGlu(1) and mGlu(5)), group II (mGlu(2) and mGlu(3)), and group III (mGlu(4), mGlu(7) and mGlu(8)) receptors, specifically modulate excitability within crucial brain structures involved in anxiety states. In addition, agonists for group II (mGlu(2/3)) receptors and antagonists for group I (in particular mGlu(5)) receptors have shown activity in animal and/or human conditions of fear, anxiety or stress. These studies indicate that metabotropic glutamate receptors are interesting new targets to treat anxiety disorders in humans.

605 citations

References
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Journal ArticleDOI
TL;DR: The prevalence of psychiatric disorders is greater than previously thought to be the case, and morbidity is more highly concentrated than previously recognized in roughly one sixth of the population who have a history of three or more comorbid disorders.
Abstract: Background: This study presents estimates of lifetime and 12-month prevalence of 14 DSM-III-R psychiatric disorders from the National Comorbidity Survey, the first survey to administer a structured psychiatric interview to a national probability sample in the United States. Methods: The DSM-III-R psychiatric disorders among persons aged 15 to 54 years in the noninstitutionalized civilian population of the United States were assessed with data collected by lay interviewers using a revised version of the Composite International Diagnostic Interview. Results: Nearly 50% of respondents reported at least one lifetime disorder, and close to 30% reported at least one 12-month disorder. The most common disorders were major depressive episode, alcohol dependence, social phobia, and simple phobia. More than half of all lifetime disorders occurred in the 14% of the population who had a history of three or more comorbid disorders. These highly comorbid people also included the vast majority of people with severe disorders. Less than 40% of those with a lifetime disorder had ever received professional treatment, and less than 20% of those with a recent disorder had been in treatment during the past 12 months. Consistent with previous risk factor research, it was found that women had elevated rates of affective disorders and anxiety disorders, that men had elevated rates of substance use disorders and antisocial personality disorder, and that most disorders declined with age and with higher socioeconomic status. Conclusions: The prevalence of psychiatric disorders is greater than previously thought to be the case. Furthermore, this morbidity is more highly concentrated than previously recognized in roughly one sixth of the population who have a history of three or more comorbid disorders. This suggests that the causes and consequences of high comorbidity should be the focus of research attention. The majority of people with psychiatric disorders fail to obtain professional treatment. Even among people with a lifetime history of three or more comorbid disorders, the proportion who ever obtain specialty sector mental health treatment is less than 50%. These results argue for the importance of more outreach and more research on barriers to professional help-seeking.

11,648 citations

Journal Article
TL;DR: It is evident that in the last decade or so, a vast amount of new information has become available concerning the various 5-HT receptor types and their characteristics, and it is important to rationalise in concert all of the available data from studies involving both operational approaches of the classical pharmacological type and those from molecular and cellular biology.
Abstract: It is evident that in the last decade or so, a vast amount of new information has become available concerning the various 5-HT receptor types and their characteristics. This derives from two main research approaches, operational pharmacology, using selective ligands (both agonists and antagonists), and, more recently, molecular biology. Although the scientific community continues to deliberate about the hierarchy of criteria for neurotransmitter receptor characterisation, there seems good agreement between the two approaches regarding 5-HT receptor classification. In addition, the information regarding transduction mechanisms and second messengers is also entirely consistent. Thus, on the basis of these essential criteria for receptor characterisation and classification, there are at least three main groups or classes of 5-HT receptor: 5-HT1, 5-HT2, and 5-HT3. Each group is not only operationally but also structurally distinct, with each receptor group having its own distinct transducing system. The more recently identified 5-HT4 receptor almost undoubtedly represents a fourth 5-HT receptor class on the basis of operational and transductional data, but this will only be definitively shown when the cDNA for the receptor has been cloned and the amino acid sequence of the protein is known. Although those 5-HT receptors that have been fully characterised and classified to date (and, hence, named with confidence) would seem to mediate the majority of the actions of 5-HT throughout the mammalian body, not all receptors for 5-HT are fully encompassed within our scheme of classification. These apparent anomalies must be recognised and need further study. They may or may not represent new groups of 5-HT receptor or subtypes of already known groups of 5-HT receptor. Even though the cDNAs for the 5-ht1E, 5-ht1F, 5-ht5, 5-ht6, and 5-ht7 receptors have been cloned and their amino acid sequence defined, more data are necessary concerning their operational and transductional characteristics before one can be confident of the suitability of their appellations. Therefore, it is important to rationalise in concert all of the available data from studies involving both operational approaches of the classical pharmacological type and those from molecular and cellular biology.(ABSTRACT TRUNCATED AT 400 WORDS)

3,069 citations

Journal ArticleDOI
TL;DR: The serotonin syndrome is a toxic condition requiring heightened clinical awareness for prevention, recognition, and prompt treatment, and further work is needed to establish the diagnostic criteria, incidence, and predisposing factors.
Abstract: Objective and method A review of the literature on the serotonin syndrome in animals and human beings was conducted, and 12 reports of 38 cases in human patients were then analyzed to determine the most frequently reported clinical features and drug interactions, as well as the incidence, treatment, and outcome of this syndrome. Findings The serotonin syndrome is most commonly the result of the interaction between serotonergic agents and monoamine oxidase inhibitors. The most frequent clinical features are changes in mental status, restlessness, myoclonus, hyperreflexia, diaphoresis, shivering, and tremor. The presumed pathophysiological mechanism involves brainstem and spinal cord activation of the 1A form of serotonin (5-hydroxytryptamine, or 5-HT) receptor. The incidence of the syndrome is not known. Both sexes have been affected, and patients' ages have ranged from 20 to 68 years. Discontinuation of the suspected serotonergic agent and institution of supportive measures are the primary treatment, although 5-HT receptor antagonists may also play a role. Once treatment is instituted, the syndrome typically resolves within 24 hours, but confusion can last for days, and death has been reported. Conclusions The serotonin syndrome is a toxic condition requiring heightened clinical awareness for prevention, recognition, and prompt treatment. Further work is needed to establish the diagnostic criteria, incidence, and predisposing factors, to identify the role of 5-HT antagonists in treatment, and to differentiate the syndrome from neuroleptic malignant syndrome.

1,148 citations

Journal ArticleDOI
TL;DR: T careful evaluation of potential drug interactions of a new drug candidate during the early stage of drug development is essential, because the smaller the difference between toxic and effective concentration, the greater the likelihood that a drug interaction will have serious clinical consequences.
Abstract: The cytochrome P450s (CYPs) constitute a superfamily of isoforms that play an important role in the oxidative metabolism of drugs. Each CYP isoform possesses a characteristic broad spectrum of catalytic activities of substrates. Whenever 2 or more drugs are administered concurrently, the possibility of drug interactions exists. The ability of a single CYP to metabolise multiple substrates is responsible for a large number of documented drug interactions associated with CYP inhibition. In addition, drug interactions can also occur as a result of the induction of several human CYPs following long term drug treatment. The mechanisms of CYP inhibition can be divided into 3 categories: (a) reversible inhibition; (b) quasi-irreversible inhibition; and (c) irreversible inhibition. In mechanistic terms, reversible interactions arise as a result of competition at the CYP active site and probably involve only the first step of the CYP catalytic cycle. On the other hand, drugs that act during and subsequent to the oxygen transfer step are generally irreversible or quasi-irreversible inhibitors. Irreversible and quasi-irreversible inhibition require at least one cycle of the CYP catalytic process. Because human liver samples and recombinant human CYPs are now readily available, in vitro systems have been used as screening tools to predict the potential for in vivo drug interaction. Although it is easy to determine in vitro metabolic drug interactions, the proper interpretation and extrapolation of in vitro interaction data to in vivo situations require a good understanding of pharmacokinetic principles. From the viewpoint of drug therapy, to avoid potential drug-drug interactions, it is desirable to develop a new drug candidate that is not a potent CYP inhibitor or inducer and the metabolism of which is not readily inhibited by other drugs. In reality, drug interaction by mutual inhibition between drugs is almost inevitable, because CYP-mediated metabolism represents a major route of elimination of many drugs, which can compete for the same CYP enzyme. The clinical significance of a metabolic drug interaction depends on the magnitude of the change in the concentration of active species (parent drug and/or active metabolites) at the site of pharmacological action and the therapeutic index of the drug. The smaller the difference between toxic and effective concentration, the greater the likelihood that a drug interaction will have serious clinical consequences. Thus, careful evaluation of potential drug interactions of a new drug candidate during the early stage of drug development is essential.

816 citations