Brain Mechanisms of Human Motivation

Multi Level Analysis of Positive Valence Systems Across Mood Disorders

This study aims to investigate reward learning across the mood disorder spectrum and to investigate the predictive validity of reward learning for subsequent symptom severity.

The study involves five sessions. In the first session, participants will play a computer task. In the second session, participants will go through a clinical interview and will have an EEG recording while playing another computer task. In the third session, participants will undergo an fMRI scan while playing another computer task. All tasks assess reward learning. At three and six months after the final session, participants will come back for a follow-up interview session during which a clinician will assess symptom severity. There will be no intervention in this study.

Inclusion Criteria:

• Written informed consent

• Right-handed

• (For mood disorder group only) Stable medication over the past 8 weeks OR absence of any psychotropic medications for at least 2 weeks (for follow-up analyses testing effects in medication-free patients):

  • 6 weeks for fluoxetine,
  • 6 months for neuroleptics,
  • 2 weeks for benzodiazepines,
  • 2 weeks for any other antidepressants
  • 4 weeks for any mood-stabilizers

Exclusion Criteria:

• Suicidal ideation where outpatient treatment is determined unsafe by the study clinician
• Pregnant women or women of childbearing potential who 1) have not completed a negative urine pregnancy test prior to the MRI scan and/or 2) are seeking to become pregnant or believe that they may be pregnant
• Serious/unstable medical illness (e.g., cardiovascular, renal, endocrine, neurologic disease)
• Clinical or laboratory evidence of hypothyroidism
• History of seizure disorder, history or current diagnosis of dementia, score < 26 on the MMSE at screening
• History or current diagnosis of the following DSM-IV psychiatric illness: organic mental disorder, schizophrenia, schizoaffective disorder, delusional disorder, psychotic disorder NOS, patients with mood congruent or mood incongruent psychotic features, anorexia nervosa, obsessive compulsive disorder
• Lifetime history of stimulant dependence (e.g., cocaine, amphetamines)
• Current use of Methylphenidate (Ritalin) and other ADHD medications with dopaminergic effects
• Patients with a lifetime history of electroconvulsive therapy (ECT)
• Failure to meet standard MRI safety requirements