Measuring Psychomotor Response to L-DOPA Challenge As a Biomarker for Outcomes in Late-Life Depression: a Pilot Feasibility Trial

Inclusion criteria

• Outpatient persons capable of providing informed consent
• Minimum age of 60 years old
• MINI International Neuropsychiatric Interview diagnosis of major depressive disorder, based on DSM-5 criteria
• MADRS score of ≥15 (moderate/severe depression)
• On stable doses of psychotropic medication, including antidepressant medication, for at least 4 weeks
• Able to adhere to the intervention schedule

Exclusion criteria

• Current diagnosis of major neurocognitive disorder
• Current active psychosis
• Unstable medical illness, including clinical or laboratory evidence of uncompensated cardiovascular, endocrine, hematologic, hepatic, pulmonary (including bronchial asthma), or renal disease
• Diagnosis of narrow angle glaucoma
• Suspicious, undiagnosed skin lesions or a history of melanoma
• History of myocardial infarction
• Atrial, nodal, or ventricular arrhythmias
• History of seizures or seizure disorder
• History of peptic ulcer disease
• History of allergy or other hypersensitivity to levodopa, carbidopa, or to any other ingredient in the formulation of Levocarb
• Active suicidal ideation
• Psychotropic medication initiation or dose change <4 weeks prior to enrolment
• Regular use of dopamine antagonist or benzodiazepines ≥2mg lorazepam equivalent per day
• Unable to complete neuropsychological testing in the English language
• Have a non-correctable clinically significant sensory impairment (i.e., cannot hear or see well enough to complete the neuropsychological tests)
• History of falls, with ≥1 fall per week during the past 4 weeks