[Ketamine and suicidal behavior: Contribution of animal models of aggression-impulsivity to understanding its mechanism of action]

More than two-thirds of suicides occur during a major depressive episode. Acting out prevention measures and therapeutic options to manage the suicidal crisis are limited. The impulsive-aggressive dimensions are vulnerability factors associated with suicide in patients suffering from a characterized depressive episode: this can be a dimension involved in animals. Impulsive and aggressive rodent models can help analyze, at least in part, the neurobiology of suicide and the beneficial effects of treatments. Ketamine, a glutamatergic antagonist, by rapidly improving the symptoms of depressive episodes, would help reduce suicidal thoughts in the short term. Animal models share with humans impulsive and aggressive endophenotypes modulated by the serotonergic system (5-HTB receptor, MAO-A enzyme), neuroinflammation or the hypothalamic-pituitary-adrenal axis and stress. Significant effects of ketamine on these endophenotypes remain to be demonstrated.

Metabolic disorders induced by psychotropic drugs

Psychotropic drugs may be associated with metabolic disorders, often but not only triggered by weight gain. Disorders include dysglycemia and diabetes, atherogenic dyslipidemia and metabolic syndrome. Overall, metabolic risk is lower with antidepressants than with antipsychotics. Among antidepressants, metabolic disorders may occur with both selective serotonin reuptake inhibitors and tricyclics, but with some between-molecule differences in each pharmacological family. Among antipsychotics, the risk is higher with second-generation (atypical) than first-generation agents. Higher risk was reported with clozapine and olanzapine, and lower risk with risperidone and aripiprazole. Weight gain is associated with increased insulin resistance, but impaired insulin secretion was also reported with clozapine and olanzapine. Metabolic disorders may be attenuated by the medication withdrawal and replacement by another safer drug. Besides deleterious effects of medications, the psychiatric population is also exposed to bad lifestyle habits (unhealthy diet and sedentary life), which also increase the risk of metabolic disorder. Management should first reinforce lifestyle measures. If this proves insufficient, specific drugs may be considered to tackle the metabolic disorder on a strategy similar to that applied in the general population.

[Ketamine Augmented Psychotherapy (KAP) in mood disorder: User guide]

Ketamine, a non-competitive NMDA receptor antagonist, is used as a fast-acting antidepressant therapy in depressive disorders. This treatment provokes dissociative effects associating derealization and depersonalization, and a synaptogenic signaling cascade promoting brain plasticity. Despite several preliminary studies suggesting the usefulness of its combination with psychotherapy, administration of ketamine isn't generally combined with per- and post-infusion psychotherapy protocols in its clinical antidepressant use. However, the phenomenology of psychodysleptic experiences and the synaptogenic effect could potentiate cognitive and behavioral therapies (CBT). In this article, we purpose a practical protocol to Ketamine Augmented Psychotherapy (KAP) synthesizing contemporary data from the literature and our clinical experience. We detail proposals for clinical practice, and propose four important steps for the use of a psychodysleptic molecule for antidepressant purposes: preparation, administration, integration, and prolongation. Finally, we discuss the limits and prospects of this combination in the management of mood disorders.

[Pharmacoresistance to psychotropic drugs in children and adolescents: Pharmacogenetic anomalies of cytochrome P450 2D6]

OBJECTIVES

Some patients in child and adolescent psychiatry present resistance to psychotropic drugs, often resulting in polytherapy, an increased risk of adverse events, and more frequent and longer hospitalisation. Psychotropic drugs are mainly metabolised in the liver, in particular by the CYP2D6 subunit of cytochrome P450. Anomalies such as a duplication of the CYP2D6 gene related to an ultra-rapid metaboliser phenotype has been described to be linked to clinical efficacy. However, little research has been done in child and adolescent psychiatry.

METHODS

A multi-centric cross-sectional study in the southeast of France explored the relation between pharmaco-resistance to psychotropic drugs and the prevalence of duplications or polymorphisms of CYP2D6 associated with an ultra-rapid phenotype in children and adolescents with severe mental health disease.

RESULTS

Twenty-two patients have been included. The presence of an ultra-rapid phenotype concerns one patient in our study. A second patient presents a slow metaboliser phenotype.

CONCLUSIONS

This study allows a clinical characterisation of the population of pediatric drug-resistant patients whose severity and the impact of their pathology are major and require long-term care associated with repeated hospitalisations, multiple drug prescriptions and numerous side effects. However, a link between drug resistance to psychotropic drugs and CYP2D6 UFM abnormalities could not be confirmed. An additional pharmacogenetic analysis by a panel of genes applied in the metabolism, transport and action of psychotropic drugs should be considered to answer questions about the resistance and independent effects of CYP2D6.

[Patterns of antidepressant dispensing among children and adolescents between 2015 and 2017 in the French region of Midi-Pyrenees]

BACKGROUND

In France, consumption of antidepressant drugs by children and teenagers has been on the rise, even though recommendations for use are limited due to their association with serious adverse reactions. The objective of this study was to describe the patterns of antidepressant drug dispensing among children and adolescents in the French region of Midi-Pyrenees.

METHOD

The data regarding the Midi-Pyrenees region were extracted from the French Health Insurance Database (SNDS) using their ATC codes. The reimbursements for antidepressants, benzodiazepines and neuroleptics dispensed to patients from 6 to 17 years old between January 2015 and June 2017 were analyzed, after which data on the antidepressants themselves were selected. The population was divided into sub-groups according to age (children : 6 to 11 years old, teenagers: 12 to 17 years old).

RESULTS

During the 30 months analyzed, 12,783 antidepressants were dispensed to 3506 patients. The antidepressants were primarily issued (90%) to teenagers. In terms of prevalence, 24.7% of the teenagers had amitriptyline delivered at least once, while 31.2% of them received sertraline at least once. Regarding total amount of antidepressant issuances, sertraline was first in both the child (26.9%) and the teenage (40.7%) populations. Benzodiazepine with an antidepressant was issued to 35.1% of the children and teenagers.

CONCLUSIONS

Amitriptyline was the most widely dispensed antidepressant among children, and sertraline among teenagers. However, fluoxetine is recommended as the first-line treatment for depression affecting this population. A psychotropic drug prescription assistance website such as psychotropes.fr addressed to general practitioners might improve the implementation of recommendations and guidelines.

[Ketamine, psilocybin, and rapid acting antidepressant: new promise for psychiatry?]

The hypothesis of monoaminergic deficiency has long dominated the conceptual framework for the development of new antidepressant strategies, but the limits of conventional antidepressant treatments targeting monoaminergic signaling have motivated the search for new antidepressant pathways. The success of ketamine in the management of depressive disorders has provoked a renewed interest in hallucinogenic substances such as psilocybin targeting the serotonergic signaling 5HT^2A and neurosteroid allosteric modulator of γ-aminobutyric acid (GABAA) receptors such as brexanolone. Unlike conventional treatments, these modulators of glutamatergic, serotonergic and GABAergic systems exert a rapid antidepressant effect ranging from 24hours to a week. Apart from their clinical interest and the fantasized search for a "miracle" molecule that jointly meets the expectations of patients and clinicians, these new targets could lead to the identification of potential new biomarkers for the development of rapid-acting antidepressants and redefine therapeutic strategies in mood disorders.

[The serotonin syndrome: An updated literature review]

The serotonin syndrome is a potentially deadly complication resulting from drug adverse effect, drug-drug interaction or overdose involving one or more serotonergic molecules, e.g., antidepressants, psychostimulants and sometimes an "ignored" serotonergic compound. The serotonin syndrome typically consists of a clinical triad including cognitive/behavioral, neurovegetative and neuromuscular features. However, this syndrome is characterized by major clinical heterogeneity, making the diagnosis difficult in practice. Moreover, many practitioners are quite unaware of this syndrome. Available scores and classifications can help physicians in their diagnosis approach. Knowing the responsible molecules, their potential interactions and mechanisms of action can help preventing this complication allowing therapeutic education among patients. This updated article reviews the clinical presentation, prevention, management, and pathophysiology of the serotonin syndrome, and addresses the most recent advances in pharmacogenetics regarding this syndrome.

[Consequences of the monoaminergic systems cross-talk in the antidepressant activity]

Selective serotonin reuptake inhibitors (SSRIs) are the most prescribed antidepressant treatment for treat major depressive disorders. Despite their effectiveness, only 30% of SSRI-treated patients reach remission of depressive symptoms. SSRIs by inhibiting the serotonin transporter present some limits with residual symptoms. Increasing not only serotonin but also norepinephrine and dopamine levels in limbic areas seems to improve remission. Anatomical relationships across serotoninergic, dopaminergic and noradrenergic systems suggest tight reciprocal regulations among them. This review attempts to present, from acute to chronic administration the consequences of SSRI administration on monoaminergic neurotransmission. The serotonin neurons located in the raphe nucleus (RN) are connected to the locus coeruleus (locus coeruleus), the key structure of norepinephrine synthesis, through GABAergic-inhibiting interneurons. Activation of the 5-HT_2A receptors expressed on GABAergic interneurons following SERT-inhibition induces an increase in serotonin leading to inhibitory effect on NE release. Similarly, the serotonin neurons exert negative regulation on dopaminergic neurons from the ventral tegmental area (VTA) through a GABAergic interneuron. These interneurons express the 5-HT_2C and 5-HT₃ receptors inducing an inhibitory effect of 5-HT on DA release. Positive reciprocal connections are also observed through direct projections from the locus coeruleus to the RN and from the VTA to the RN through α₁ and D₂ receptors respectively, both stimulating the serotoninergic activity. Acute SSRI treatment induces only a slight increase in 5-HT levels in limbic areas due to the activation of presynaptic 5-HT_1A and 5-HT_1B autoreceptors counteracting the effects of the transporter blockade. No change in NE levels and a small decrease in the dopaminergic neurotransmission is also observed. These weak changes in monoamine in the limbic areas after acute SSRI treatment seems to be one of key point involved in the onset of action. Following desensitization of the 5-HT_1A and 5-HT_1B autoreceptors, chronic SSRI treatment induces a large increase in the 5-HT neurotransmission. Changes in 5-HT levels at the limbic areas results in a decrease in NE transmission and an increase in DA transmission through an increase in the post-synaptic D₂ receptors sensitivity and not from a change in DA levels, which is mainly due to a desensitization of the 5-HT_2A receptor. The observed decrease of NE neurotransmission could explain some limits of the SSRI therapy and the interest to activate NE system for producing more robust effects. On the other hand, the D₂ sensitization, especially in the nucleus accumbens, stimulates the motivation behavior as well as remission of anhedonia considering the major role of DA release in this structure. Finally, we need to take into account the key role of each monoaminergic neurotransmission to reach remission. Targeting only one system will limit the therapeutic effectiveness. Clinical evidences, including the STAR*D studies, confirmed this by an increase of the remission rate following the mobilization of several monoaminergic transmissions. However, these combinations cannot constitute first line of treatment considering the observed increase of side effects. Such an approach should be adapted to each patient in regard to its particular symptoms as well as clinical history. The next generation of antidepressant therapy will need to take into consideration the interconnections and the interrelation between the monoaminergic systems.

[Pharmacological properties of vortioxetine and its pre-clinical consequences]

Selective Serotonin Reuptake Inhibitors (SSRIs) are extensively used for the treatment of major depressive disorder (MDD). SSRIs are defined as indirect receptor agonists since the activation of postsynaptic receptors is a consequence of an increase in extracellular concentrations of serotonin (5-HT) mediated by the blockade of serotonin transporter. The activation of some serotoninergic receptors (5-HT1A, post-synaptic, 5-HT1B post-synaptic, 5-HT2B, and 5-HT4), but not all (5-HT1A, pre-synaptic, 5-HT1B pre-synaptic, 5-HT2A, 5-HT2C, 5-HT3, and probably 5-HT6), induces anxiolytic/antidepressive - like effects. Targetting specifically some of them could potentially improve the onset of action and/or efficacy and/or prevent MD relapse. Vortioxetine (Brintellix, 1- [2-(2,4-dimethylphenyl-sulfanyl)-phenyl]-piperazine) is a novel multi-target antidepressant drug approved by the Food and Drug Administration (FDA) and by European Medicines Agency. Its properties are markedly different from the extensively prescribed SSRIs. Compared to the SSRIs, vortioxetine is defined as a multimodal antidepressant drug since it is not only a serotonin reuptake inhibitor, but also a 5-HT1D, 5-HT3, 5-HT7 receptor antagonist, 5-HT1B receptor partial agonist and 5-HT1A receptor agonist. This specific pharmacological profile enables vortioxetine to affect not only the serotoninergic and noradrenergic systems, but also the histaminergic, cholinergic, gamma-butyric acid (GABA) ergic and glutamatergic ones. Thus, vortioxetine not only induces antidepressant-like or anxiolytic-like activity but also improves cognitive parameters in several animal models. Indeed, vortioxetine was shown to improve working memory, episodic memory, cognitive flexibility and spatial memory in young adult rodents and also in old animal models. These specific effects of the vortioxetine are of interest considering that cognitive dysfunction is a common comorbidity to MDD. Altogether, even though this molecule still needs to be investigated further, especially in the insufficient-response to antidepressant drugs, vortioxetine is already an innovative therapeutic option for the treatment of major depression.

[Depressive symptoms during anorexia nervosa: State of the art and consequences for an appropriate use of antidepressants]

OBJECTIVE

Depressive comorbidity is often associated with anorexia nervosa (AN), and antidepressant medication is widely used although it does not rely on any convincing data in the scientific literature. Our objectives were: to summarize the epidemiological, physiological, psychopathological literature about the relation between AN and manifestations of depression, and to focus on the clinical trial data assessing the use of antidepressant medication in AN in order to clarify the strategy for the use of antidepressant in AN during adolescence.

METHOD

A manual computerised search (Medline) was performed for relevant published studies assessing the association between depressive signs or Major Depressive Disorder (MDD) and AN. Another manual computerised search (Medline) listed clinical trials assessing antidepressant in AN.

RESULTS

On the one hand, depressive symptoms are common during the course of AN and could have different meaning. Indeed, firstly, we can distinguish symptoms that are inherent to AN and which can be mistaken for depressive signs (for instance: low self-esteem, reduced social contacts). Secondly, long-term undernourishment can be held responsible for numerous psychological distortions, including anxiety and depression symptoms such as insomnia, impaired concentration, or social isolation. Thirdly, the natural course of AN can also lead to "depressive moments", in particular when switching to a "purging type" AN, or when recovery mobilizes control and narcissistic issues. On the other hand, MDD is also highly prevalent among AN patients and is a negative prognosis factor. Thus, it is complex to differentiate MDD from isolated depressive symptoms that could be inherent of the AN symptomatology which raises the question of the role of antidepressant medication in treatment of depression in AN. No significant benefit of antidepressant medication in AN has been shown in clinical trials, and according to international guidelines it should be prescribed only as a second-line treatment, after appropriate refeeding, and in case of an authentic depressive disorder. Those data appear to be in contradiction with the frequent use of those drugs in clinical practice.

DISCUSSION

Nevertheless, clinical trials assessing antidepressant treatment in AN suffer from methodological weakness concerning the size of the sample, the choice of the population or the evaluation criterion. This lack of proof must raise our vigilance concerning antidepressant medication in AN but should not categorically prevent the clinician from using it when necessary. We do believe that there are some indications for prescribing antidepressant in patients with AN. The clinical challenge lies in the differentiation of the depressive symptoms that are transitory and likely to improve without medication from those that signal the presence of an MDD. Three criterion could be indicative of MDD: familial history of mood disorder, as it is a major risk factor for MDD among relatives; the chronology of appearance of both disorders, when MDD pre-exists AN; a few specific symptoms cannot be attributed to undernourishment or reactive depressive signs, such as morning insomnia, daily variation of depressive symptoms, suicidal attempts or ideation and guilt ideation. Thus, in integrating the data from the literature review, we propose a pragmatic therapeutic strategy for the use of an antidepressant in AN during adolescence that lies in 3 main categories for depressive manifestations in AN: therapeutic emergencies: when an obvious and severe MDD is comorbid to AN, immediate antidepressant would be required; isolated and non-specific depressive sign: no medication would be relevant as they are supposed to improve with refeeding and psychotherapeutic support; intermediary patterns which is probably the most frequent situation. In the last case, it would be relevant to abstain from prescribing medication in first line, but an antidepressant medication should be quickly considered in the presence of one (or several) criterion listed above and its persistence despite refeeding. The general medical state of this fragile population of patients should be evaluated (standard blood test, ECG) before and during treatment.

[Antidepressant and tolerance: Determinants and management of major side effects]

Antidepressant therapy aims to reach remission of depressive symptoms while reducing the complications and risks of relapse. Even though they have proven their efficacy, it takes several weeks for antidepressants to demonstrate full effectiveness, and adverse effects occur more quickly or (quicker) which can be a source of poor compliance. This latest aspect often leads to dose reduction and/or change of molecule that have the effect of delaying remission. This review attempts to present, from the pharmacological properties of the major classes of antidepressants (monoamine oxidase inhibitor [MAOI], tricyclic antidepressants [TCA], selective serotonin reuptake inhibitor [SSRI] and serotonin and noradrenaline reuptake inhibitor [SNRI]), to the pharmacological mechanisms involved in adverse effects by focusing on sexual dysfunction, nausea/vomiting, and weight changes and sleep disruption. If the activation of dopamine D_1/2 or norepinephrine receptors through the autonomic nervous system controls and facilitates sexual desire, increasing serotoninergic transmission through 5-HT_1B/2A/2C receptors activation inhibits this process. The pharmacological properties of drugs inducing nausea/vomiting activate opiate receptors μ, increase dopaminergic and serotoninergic transmission activating the dopamine D₂ and serotonin 5-HT₃ receptors, respectively. Among the causes responsible for weight gain under antidepressant therapy, monoamine neurotransmission still plays an important role. The blockade of serotonin 5-HT_2C or histamine H₁ receptors is directly responsible for weight gain. Finally, the activation of 5-HT_1A/1B/3/7 serotoninergique receptors modulates wakefulness, raid eyes movement or sleep duration. In conclusion, if antidepressant activity of SERT or MAO inhibitors is an indirect consequence of postsynaptic 5-HT, DA, NA receptor activation, it is also responsible for side effects, causes of poor compliance and hence therapeutic failures. Finally, we need to take into account the key role of the nocebo effect in the occurrence of adverse effects. The next generation of antidepressant would aim to have a rapid efficacy in patients unresponsive or resistant to drugs currently available while improving certain effects of tolerance through an optimization of their psychopharmacological properties leading to a reduction of their side effects.