Antidepressant response to a single subanesthetic dose infusion of the glutamatergic modulator ketamine is transient in most depressed patients; however, a minority continue to experience an extended response. This study examined depressive symptoms and potential clinical predictors of extended response to ketamine in subjects with mood disorders. Subjects were diagnosed with either major...
We previously found that body mass index (BMI) strongly predicted response to ketamine. Adipokines have a key role in metabolism (including BMI). They directly regulate inflammation and neuroplasticity pathways and also influence insulin sensitivity, bone metabolism and sympathetic outflow; all of these have been implicated in mood disorders. Here, we sought to examine the role of three key...
Several pro-inflammatory cytokines have been implicated in depression and in antidepressant response. This exploratory analysis assessed: 1) the extent to which baseline cytokine levels predicted positive antidepressant response to ketamine; 2) whether ketamine responders experienced acute changes in cytokine levels not observed in non-responders; and 3) whether ketamine lowered levels of...
OBJECTIVE: Insomnia and disrupted sleep are associated with increased risk of suicide. The N-methyl-d-aspartate antagonist ketamine has been associated with reduced suicidal thoughts, but the mechanism of action is unknown. This study sought to evaluate differences in nocturnal wakefulness in depressed individuals who did and did not have an antisuicidal response to ketamine. METHODS:...
In patients with major depressive disorder (MDD) or bipolar disorder (BD), abnormalities in excitatory and/or inhibitory neurotransmission and neuronal plasticity may lead to aberrant functional connectivity patterns within large brain networks. Network dysfunction in association with altered brain levels of glutamate (Glu) and gamma-aminobutyric acid (GABA) have been identified in both animal...
Major depressive disorder affects around 16 per cent of the world population at some point in their lives. Despite the availability of numerous monoaminergic-based antidepressants, most patients require several weeks, if not months, to respond to these treatments, and many patients never attain sustained remission of their symptoms. The non-competitive, glutamatergic NMDAR (N-methyl-d-aspartate...
Current pharmacotherapies for major depressive disorder (MDD) have a distinct lag of onset that can prolong distress and impairment for patients, and realworld effectiveness trials further suggest that antidepressant efficacy is limited in many patients. All currently approved antidepressant medications for MDD act primarily through monoaminergic mechanisms, e.g., receptor/reuptake agonists or...
Background Ketamine and non-ketamine N-methyl-d-aspartate receptor antagonists (NMDAR antagonists) recently demonstrated antidepressant efficacy for the treatment of refractory depression, but effect sizes, trajectories and possible class effects are unclear. Method We searched PubMed/PsycINFO/Web of Science/clinicaltrials.gov until 25 August 2015. Parallel-group or cross-over randomized...
Current therapeutic options for major depressive disorder (MDD) and bipolar disorder (BD) are associated with a lag of onset that can prolong distress and impairment for patients, and their antidepressant efficacy is often limited. All currently approved antidepressant medications for MDD act primarily through monoaminergic mechanisms. Glutamate is the major excitatory neurotransmitter in the...
All currently approved antidepressant medications for major depressive disorder (MDD) and bipolar disorder act primarily on the monoaminergic system and have varying affinities for serotonergic, norepinephrine-ergic, and/or dopaminergic receptors. Unfortunately, these drugs are only effective in approximately two-thirds of patients. Glutamate is the major excitatory neurotransmitter in the...
Major depressive disorder and bipolar depression are among the most prevalent and disabling mental disorders worldwide. Real-world effectiveness trials in major depressive disorder have underscored that most pharmacological options target monoamines, which are involved in a minority (15-20%) of synaptic contacts in the mammalian brain. Most synapses (∼50%) use the amino acid glutamate as their...
Studies that evaluate agents with potentially rapid antidepres-sant effects are critical to developing new, improved treat-ments for major mood disorders. In particular, such studiesmay offer key insights into the mechanism of action of rapid-acting antidepressants as well as the neurobiology of mooddisorders (1). In their excellent article published in this issue ofBiological Psychiatry,...
Current pharmacotherapies for major depressive disorder (MDD) and bipolar depression (BDep) have a distinct lag of onset that can generate great distress and impairment in patients. Furthermore, as demonstrated by several real-world effectiveness trials, their efficacy is limited. All approved antidepressant medications for MDD primarily act through monoaminergic mechanisms, agonists or...
Anhedonia is a cardinal symptom of major depression and is often refractory to standard treatment, yet no approved medication for this specific symptom exists. In this exploratory re-analysis, we assessed whether administration of rapid-acting antidepressant ketamine was associated specifically with reduced anhedonia in medication-free treatment-refractory patients with major depressive...
Ketamine and lithium both inhibit glycogen synthase kinase 3. In addition, lithium and ketamine have synergistic antidepressant-like effects at individually subeffective doses in rodents. We hypothesized that ketamine's antidepressant effects would be improved by therapeutic doses of lithium versus valproate and that serum lithium levels would positively correlate with ketamine's antidepressant...
BACKGROUND: A single subanesthetic infusion of the N-methyl-D-aspartate (NMDA) receptor antagonist ketamine has rapid and potent antidepressant properties in treatment-resistant major depressive disorder (TRD). As a family history of an alcohol use disorder is a positive predictor of ketamine's antidepressant response and the strength of the association increases over time, we hypothesized that...
OBJECTIVE: Patents with anxious bipolar disorder have worse clinical outcomes and are harder to treat with traditional medication regimens compared to those with non-anxious bipolar disorder. Ketamine has been shown to rapidly and robustly decrease symptoms of depression in depressed patients with bipolar disorder. We sought to determine whether baseline anxiety status reduced ketamine's...
BACKGROUND: The neural correlates of suicidal ideation and its reduction after treatment are unknown. We hypothesized that increased regional cerebral glucose metabolism in the infralimbic cortex (Brodmann area 25), amygdala, and subgenual anterior cingulate cortex would be associated with suicidal ideation and its reduction after ketamine infusion. METHODS: Medication-free patients (n=19) with...
Anhedonia--which is defined as diminished pleasure from, or interest in, previously rewarding activities-is one of two cardinal symptoms of a major depressive episode. However, evidence suggests that standard treatments for depression do little to alleviate the symptoms of anhedonia and may cause reward blunting. Indeed, no therapeutics are currently approved for the treatment of anhedonia....
OBJECTIVE: Patients with anxious depression are typically more difficult to treat with monoaminergic antidepressants compared to those with nonanxious depression. Although novel research has shown that the N-methyl-D-aspartate (NMDA) receptor antagonist ketamine has rapidly acting, relatively sustained effects in treating depression, we predicted that, consistent with the existent literature on...
(R,S)-ketamine is a rapid and effective antidepressant drug that produces a response in two thirds of patients with treatment-resistant depression (TRD). The underlying biochemical differences between a (R,S)-ketamine responder (KET-R) and non-responder (KET-NR) have not been definitively identified but may involve serine metabolism. The aim of the study was to examine the relationship between...
INTRODUCTION: Deficiencies in both vitamin B12 and folate have been associated with depression. Recently, higher baseline vitamin B12 levels were observed in individuals with bipolar depression who responded to the antidepressant ketamine at 7 days post-infusion. This study sought to -replicate this result by correlating peripheral vitamin levels with ketamine's antidepressant efficacy in...
OBJECTIVE: The N-methyl-D-aspartate receptor antagonist ketamine has rapid antidepressant effects in treatment-resistant major depressive disorder (MDD) and bipolar depression. Clinical predictors may identify those more likely to benefit from ketamine within clinically heterogeneous populations. METHOD: Data were analyzed from 4 studies of treatment-resistant inpatients with...
(R,S)-ketamine produces rapid and significant antidepressant effects in approximately 65% of patients suffering from treatment-resistant bipolar depression (BD). The genetic, pharmacological and biochemical differences between ketamine responders and non-responders have not been identified. The purpose of this study was to employ a metabolomics approach, a global, non-targeted determination of...
Background The N-methyl-D-aspartate receptor antagonist ketamine has rapid antidepressant effects in major depression. Psychotomimetic symptoms, dissociation and hemodynamic changes are known side effects of ketamine, but it is unclear if these side effects relate to its antidepressant efficacy. Methods Data from 108 treatment-resistant inpatients meeting criteria for major depressive disorder...