Paliperidone augmentation for treatment-resistant depression: a case report

Second Generation Antipsychotics in the Treatment of Major Depressive Disorder: An Update

Less than one third of patients who suffer from major depressive disorder (MDD) report remission following antidepressant treatments requiring more diverse treatment approaches. Augmentation of second generation antipsychotics (SGAs) has been increasingly recognized as an important treatment option. The authors have previously provided a comprehensive review of SGAs for the treatment of MDD in 2013. Since then, numerous additional clinical trials have been conducted to investigate diverse issues regarding the utility of SGAs in MDD. Moreover, a new SGA, brexpiprazole, was recently approved by the Food and Drug Administration in July 2015 for the treatment of MDD as an augmentation agent to antidepressants. Thus, the aim of this study was to provide a concise update of all the available SGAs for the treatment of MDD, in particular on the additional clinical trials which have been published since 2013.

Use of second generation antipsychotics for treatment-resistant major depressive disorder

Many of the second generation antipsychotics (SGAs) have been studied as adjunctive agents in the management of treatment-resistant major depressive disorder. Two have also been examined for use as monotherapy for depression. Currently, aripiprazole, olanzapine (in combination with fluoxetine), and quetiapine XR are approved by the FDA for use as adjunctive agents in the treatment of major depressive disorder, and no SGAs are FDA-approved as monotherapy for the disorder. This article reviews the available evidence regarding the use of SGAs in patients with treatment-resistant major depressive disorder and the subsequent role for these agents based on this evidence. There is evidence that aripiprazole, quetiapine, olanzapine, and risperidone can be effective in improving depressive symptoms when added to antidepressant therapy, but the benefits have to be weighed against their risk of producing serious adverse effects.

Active metabolites as antidepressant drugs: the role of norquetiapine in the mechanism of action of quetiapine in the treatment of mood disorders

Active metabolites of some antipsychotic drugs exhibit pharmacodynamic and pharmacokinetic properties that may be similar to or differ from the original compound and that can be translated by a different profile of responses and interactions to clinical level. Some of these antipsychotics' active metabolites might participate in mechanisms of antidepressant activity, as m-chlorophenylpiperazine (aripiprazole), 9-OH-risperidone and norquetiapine. Norquetiapine exhibits distinct pharmacological activity from quetiapine and plays a fundamental role in its antidepressant efficacy. In this review, we analyze the differential pharmacological aspects between quetiapine and norquetiapine, both from the pharmacokinetic and pharmacodynamic perspectives (affinity for dopaminergic, noradrenegic, and/or serotonergic receptors, etc.), as well as differential neuroprotective role. The pharmacological differences between the two drugs could explain the differential clinical effect, as well as some differences in tolerability profile and drug interactions. The available data are sufficient to arrive at the conclusion that antidepressant activity of quetiapine is mediated, at least in part, by the active metabolite norquetiapine, which selectively inhibits noradrenaline reuptake, is a partial 5-HT1A receptor agonist, and acts as an antagonist at presynaptic α2, 5-HT2C, and 5-HT7 receptors.