Active clinical trials for "Depressive Disorder, Major"

Pregnenolone, an over-the-counter supplement, is a naturally occurring neurosteroid made in the adrenal glands and brain. Preclinical research suggests pregnenolone has antidepressant, cognitive enhancing, and neuroprotective properties, particularly in women. The following hypothesis will be tested in this trial: pregnenolone is associated with improvement in depressive symptom severity in women that is associated with changes in the resting state functional connectivity (rsFC) and GABA.

The study examines whether people primarily want to confirm their prior attitudes in health-related information search, in an online environment using social tags for navigation. Participants were looking for information on the treatment of depression with antidepressants and psychotherapy. They were randomly assigned to two groups with either high or low credibility of the community who provides social tags, and two groups where participants' confidence in prior attitudes was heightened or lowered, and to two groups where either antidepressant tags were more popular or psychotherapy was more popular. The investigators measured attitude change toward the treatments and also navigation behavior.

Transcranial magnetic stimulation (rTMS) is an investigational and therapeutic modality that impacts the connection strength between neurons by delivering patterned energy. In response to this patterned energy neurons fire and adapt by changing their connection strengths. This change in connection strengths is believed to be the underlying mechanism whereby this intervention has therapeutic benefit for this intervention in conditions such as depression. The purpose of this study is to test a means of enhancing the effect of rTMS using a medication (cycloserine) that has been shown to augment and stabilize activity dependent neuronal changes. The investigators wish to use the motor system, where the associated muscle response to brain stimulation can be measured, to probe activity dependent changes in connection strength between neurons.

This study will evaluate the short term effects of respiratory-gated transcutaneous vagus nerve stimulation on the regulation of cardiovagal activity, depressive symptomatology and immune function in subjects with major depression and determine the optimal stimulation frequency for this population.

Attaining goals or rewards commonly entails response costs. In light of cost and benefits, how do participants decide what effort should be put in to give it a shot? Figuratively, you may "go with your gut", but the literal contribution of the gut-brain axis in allocating effort is poorly understood to date. Here, the investigators propose to investigate non-invasive transcutaneous vagal nerve stimulation (tVNS) as a potential modulator of energy metabolism and response vigor. Since the neural mechanisms causing the diverse cognitive and behavioral effects of the stimulation remain largely elusive, the investigators will use computational modeling of instrumental behavior and determine the primary metabolic effects of the stimulation. The investigators hypothesize that tVNS will lead to activation of afferent targets in the brain. In turn, the elicited brain activation is expected to mediate the cognitive effects of the stimulation. This may affect both sides of the utility equation because anti-depressive effects may correspond to boosting the benefit of effort whereas anti-nociceptive effects may reduce perceived costs of effort. Collectively, dissecting the cognitive effects of non-invasive tVNS in healthy individuals may facilitate the more widespread use as a treatment in mental disorders that are characterized by metabolic alterations such as depression.

The study is looking at assessing monoamine oxidase B (MAO-B) occupancy in depressed patients before and after medication treatment using positron emission tomography (PET) scan.

This study is being conducted to understand the use of a mobile app (titled Pathway) to help patients track depression symptoms, medications, side effects, and goals in addition to the usual care with their doctor. Investigators will compare the effect of the app over 6 months and examine whether the app can increase engagement between patients and their doctor and help in the management of illnesses as patients start a new treatment for depression. The investigators hope that using an app to facilitate management of depression symptoms, medication use, and side effects will help patients and their providers understand their response to medications and lead to better response and improvements in depression.

Insufficient cognitive control over emotional distracters is characteristic for major depressive disorder (MDD). Hypoactivation of the dorsolateral prefrontal cortex (dlPFC) is associated with this deficit. In this study the investigators assess the effect of an enhancement of dlPFC activity in MDD patients by anodal transcranial direct current stimulation (tDCS) on cognitive control. In a double-blinded, balanced randomized, sham-controlled crossover trial the investigators determine the effect of a single-session tDCS to the left dlPFC on cognitive control in MDD patients and healthy controls. To assess the cognitive control the investigators use a delayed response working memory (DWM) task with pictures of varying valence presented during the delay period.

This study is designed to look at that involvement of a process in the brain called the glutamate system in depression. Participants will undergo a screening session, up to two functional Magnetic Resonance Imaging (fMRI) scans, and up to three Positron Emission Tomography (PET) scans, as well as cognitive testing at each scan session. For one of the PET scans, a drug (either ketamine or n-acetyl cysteine) will be administered. Hypothesis 1: The investigators hypothesize administration of ketamine or n-acetylcysteine (NAC) will lead to a decrease in mGluR5. Hypothesis 2: The investigators hypothesize an improvement in memory and attentional skills after drug challenge. Hypothesis 3: The investigators hypothesize an increase in mGluR5 availability and change in MRI measures post drug challenge as compared to baseline, signifying synaptogenesis. Hypothesis 4: We expect there should not be a significant difference in reduction in mGluR5 availability due to differences in ABP688 radiotracer infusion.

The purpose of this study is to evaluate the safety of PDC-1421 Capsule in healthy subject, find the effective adequate dose for the next stage of the study, and accumulate information of possible mechanism of its anti-depressive effect.