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.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
OTHER
Masking
NONE
Enrollment
56
Patients will be provided 50mg dose of desvenlafaxine for 1 week titrated up to 100mg dose of desvenlafaxine for 7 weeks.
St. Michael's Hospital
Toronto, Ontario, Canada
Measuring Reward association and valuation using the Reward Association Task
Based on signal detection theory, it evaluates response bias as a function of prior reward and permits an objective assessment of disorder-related sensitivity to reward. To evaluate the how the 6 facets of reward are related to each other in unmedicated MDD patients in order to develop a clearer understanding of reward pathways
Time frame: Change from Baseline at 8 Weeks
Measuring Expectation using a prediction error task, to measure learning and choosing, during functional Magnetic Resonance Imaging (fMRI)
This distinction was included in the design in order to dissociate potentially different neural circuits subserving learning reward associations and using them to guide behavior. To evaluate the how the 6 facets of reward are related to each other in unmedicated MDD patients in order to develop a clearer understanding of reward pathways
Time frame: Change from Baseline at 8 Weeks
Anticipation of reward using the monetary incentive delay during fMRI
This task was designed to disentangle anticipatory vs. consummatory phases of reward processing. To evaluate the how the 6 facets of reward are related to each other in unmedicated MDD patients in order to develop a clearer understanding of reward pathways
Time frame: Change from Baseline at 8 Weeks
Motivation/effort using the Cued-Reinforcement Reaction Time Task and the EEfRT task.
The Cued-Reinforcement Reaction Time Task (CRRT) provides an evaluation of reward-based reaction time speed as an index of incentive motivation.The EEfRT task allows analysis of the predictive value of reward probability and magnitude on effort-based decision making. To evaluate the how the 6 facets of reward are related to each other in unmedicated MDD patients in order to develop a clearer understanding of reward pathways
Time frame: Change from Baseline at 8 Weeks
Pleasure/Liking using the monetary incentive delay task in an fMRI
This task was designed to disentangle anticipatory vs. consummatory phases of reward processing. To evaluate the how the 6 facets of reward are related to each other in unmedicated MDD patients in order to develop a clearer understanding of reward pathways. To evaluate the how the 6 facets of reward are related to each other in unmedicated MDD patients in order to develop a clearer understanding of reward pathways
Time frame: Change from Baseline at 8 Weeks
Feedback integration using the Probabilistic Reversal Learning task during fMRI
participants are presented with a choice of two stimuli. Based on their first choice, the selected stimulus will be rewarded with a high probability, while the other will be rewarded with a low probability.To evaluate the how the 6 facets of reward are related to each other in unmedicated MDD patients in order to develop a clearer understanding of reward pathways
Time frame: Change from Baseline at 8 Weeks
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.