Active clinical trials for "Anhedonia"

Investigating whether delta-beta cross-frequency transcranial alternating current stimulation can increase goal-directed behavior in participants with major depressive disorder and elevated symptoms of anhedonia.

The most widely-accepted animal model of nicotine withdrawal states stopping nicotine makes rewarding events become less rewarding. The current study will test if this is true in humans. If we find tobacco abstinence does make rewards less rewarding, this would suggest new symptoms to add to official descriptions of nicotine withdrawal. It would also suggest we need to develop new behavioral and pharmacological interventions to correct this problem. If stopping smoking does not make rewards less rewarding, this would suggest this animal model does not apply to the human condition and we need to continue to search for an animal model of tobacco withdrawal that is relevant to smokers stopping smoking.

The purpose of this research study is to investigate how the brain processes emotions, and the way these processes affect behavior. Specifically, we hypothesize that individual differences in reward responsiveness will correlate with differential activation in mesolimbic regions of the brain and predict future wellbeing in follow-up interviews.

The overall aim of this study is to utilize an integrative research model in order to dynamically assess reward-related dopamine (DA) transmission in major depressive disorder (MDD) and test the role of dysfunctional DA release in depression and anhedonia. The first arm of this line of research (PET scan) aims to investigate phasic DA release in MDD during incentive motivation. The investigators will utilize an established molecular imaging technique to measure striatal DA release dynamically during performance of testing and control versions of a monetary incentive delay task, which involves anticipation and receipt of monetary rewards. In doing so, this experiment will link together independent lines of research that have associated depression with decreased hedonic responsiveness, impaired reinforcement learning and dysfunctional DA transmission. We hypothesize that, relative to matched controls, unmedicated MDD subjects will show reduced reward-related ligand (11C-raclopride) displacement. Reduced ligand displacement will be interpreted as indicating reduced task-induced release of endogenous striatal DA in response to reward-predicting cues and unpredictable reward in MDD subjects. In the second arm of this research (EEG recording), the investigators aim to probe the spatio-temporal dynamics of brain mechanisms underlying positive and negative reinforcement learning in MDD and their relations to phasic DA. Participants will perform the probabilistic stimulus selection task (PSST) while event-related potentials (ERPs) are collected. The investigators expect that, relative to matched controls, unmedicated MDD subjects will show reduced positive reinforcement learning, potentiated negative reinforcement learning, and larger (i.e., more negative) feedback-related negativity (FRN) in response to positive reinforcement (indicative of reduced DA transmission). Moreover, the investigators hypothesize that a more negative FRN in response to positive reinforcement will be associated with decreased striatal raclopride displacement (i.e., lower release of endogenous DA) as measured by PET in the first part of the study. This experiment will investigate the effects of blunted DA transmission on behavioral and ERP markers of both positive and negative reinforcement learning.

Anhedonia (the lack of pleasure in normally pleasurable things) is a common symptom of major depressive disorder (MDD), and it may impact how patients with depression experience reward. Understanding how anhedonia is related to the experience of reward may help improve how depression is treated. Computer tasks can be used to measure how reward is experienced, and these measures might be able to predict things like who is likely to become depressed, or who will respond to antidepressant medication. Studying the relationship between anhedonia and reward in patients with depression might also tell us something about how to improve diagnosis and treatment of other psychiatric disorders.This is an open label controlled treatment study lasting 8 weeks. The brain scans will be used to find changes in brain areas that may be related to how people perform on the tasks. The investigators goal is to use this information to help us find a reliable predictor that can be used to guide MDD treatment.

This study will use magnetic resonance imaging (MRI) to examine how the brain regulates emotions in healthy people and in patients who have major depression and anhedonia (loss of feeling of pleasure in things that normally give pleasure). Healthy normal volunteers and patients between 18 and 50 years of age with major depression, with or without significant anhedonia, are eligible for this study. Candidates will be screened with a psychiatric interview, a physical examination that will include blood and urine samples, and an electrocardiogram, and a questionnaire about their emotions. Participants will perform a monetary reward task while lying in an MRI scanner. The task is similar to playing a computer video game with the possibility of winning cash. The amount of cash is largely dependent on the subject's performance. The accumulated amount of cash earned in a session will fluctuate depending on the subject's continuing performance level. That is, during a single session, a subject could lose money earned early in the session if his or her performance later in the session is not as good as earlier. MRI pictures will be taken during performance of the task. MRI uses a magnetic field and radio waves to produce images of body tissues and organs. The patient lies on a table that is moved into the scanner (a narrow cylinder) and wears earplugs to muffle loud knocking and thumping sounds that occur during the scanning process. The procedure will last about 1 to 1-1/2 hours.

Anhedonia, decreased motivation for and sensitivity to rewarding experiences, is present in at least 1/3 of community dwelling older adults and is a feature of various psychiatric and neurological disorders, including late-life depression and Parkinson's disease. Anhedonia is associated with cognitive deficits, as well as poor clinical outcomes and increased mortality. Recent research suggests that anhedonia comprises motivational (reward "wanting") and consummatory (reward "liking") aspects. However, previous research on anhedonia has failed to dissociate these components, which may explain the contradictory findings in the literature. Recently, the Effort-Expenditure for Rewards Task (EEfRT) was developed in an effort to dissociate reward components in anhedonia. The EEfRT is an effort-based decision-making task that measures reward "wanting", in contrast to commonly used anhedonia questionnaires, which focus on reward "liking." This novel task may provide a useful measure of components of anhedonia in older adults and in different patient populations. Thus far no data is available on this task in elderly individuals, and the cognitive and neural correlates of components of the task have not been investigated. Given the paucity of research on the neurobiology of anhedonia, cognitive neuroscience studies using this task could fill a gap in the literature. The investigators are developing a line of cognitive neuroscience studies examining anhedonia in community-dwelling older adults and in late-life depression and Parkinson's disease. This study will involve gathering pilot behavioral and functional magnetic resonance imaging (fMRI) data in young and older adults performing the EEfRT task. Understanding the brain mechanisms underlying anhedonia in older adults and in different patient populations will have a translational impact by elucidating biological targets for treatment.

The purpose of this study is to use positron emission tomography (PET) imaging to measure the activity of the kappa opioid receptor (KOR) in the brains of depressed and non-depressed individuals.

Anhedonia and abnormalities in reward behavior are core features of overweight/obesity (OW), a highly prevalent condition within MDD populations, and is independently associated with reward disturbances. The investigators therefore aim to investigate the brain substrates subserving reward and motivation in adults with overweight/obesity. The primary aim of this pilot study is to determine whether associations exist between obesity and decreased performance on the respective motivation/reward paradigms.

Deficits or abnormalities in reward processing are present in a number of psychiatric disorders. The overarching objective of the study is to conduct initial validation work towards optimising three experimental tasks - which have previously been shown to be sensitive to reward processing deficits - for future use in clinical trials. This initial validation work has the primary objective to uncover group differences in task outcome measures between healthy control participants, participants with Major Depressive Disorder (MDD) and participants with schizophrenia (SZ) using statistical analyses. This may provide some indications for the use of these tasks as clinically-relevant biomarkers. Primary aims include: (i) comparing the investigator's endpoint means and distributions to those in previously published data; (ii) replication of previously-reported differences between MDD/SZ vs. healthy control participants, and, (iii) exploring the relationship between task endpoints and subjective participant- and clinician-rated report of reward-related constructs (e.g. anhedonia, negative symptoms).