After reviewing Theodore's case history, it is my professional recommendation that increasing exposure to natural sunlight should be prioritized during his daily work hours. Individuals with major depressive disorder often exhibit improved mood and regulation of circadian rhythms when spending more time outdoors and exposed to ample natural light.
Given that Theodore currently works long hours in a poorly lit indoor office environment, he would likely benefit from taking regular outdoor walking breaks during lunch and afternoon hours. When feasible, he could also request a standing desk area situated close to a window. Incorporating full-spectrum lighting, houseplants, or other sun-simulating elements into his indoor office space may also be advisable.
While more dramatic lifestyle changes like switching careers may not be feasible presently, even small modifications to increase Theodore's daily exposure to natural daylight could provide mood-enhancing results. Prior research clearly indicates the benefits of sunlight on serotonin production and circadian regulation for those with depression. Making practical steps like taking more frequent outdoor breaks during the workday is a simple yet impactful lifestyle change I would recommend at this juncture. I am happy to address any additional questions or concerns you may have regarding my advised course of action.