Estimation of Control Before and After Treatment of a Depressive Episode With Serotonin Reuptake Inhibitors

Inclusion Criteria - applicable to all participants: * Affiliated with a social security or national health insurance system, or entitled to such coverage. * Male or female, aged 18 to 55 years. * Fluent in spoken and written French. * Normal or corrected-to-normal vision. * Access to a computer and an internet connection. * Available for the 8-week study period following treatment initiation (patients) or the baseline visit (healthy controls). * Willing to use an effective method of contraception (condom, oral contraceptive pill, abstinence, or intrauterine device). Additional inclusion criteria for the depressed patient group: * Eligible for antidepressant monotherapy with a selective serotonin reuptake inhibitor (SSRI: sertraline, fluoxetine, citalopram, or paroxetine) or a serotonin-norepinephrine reuptake inhibitor (SNRI: venlafaxine or duloxetine), with or without concomitant treatment with a short half-life benzodiazepine (\<12 hours; e.g., oxazepam, lorazepam, or clotiazepam), for which the prescription has been issued but treatment has not yet been initiated. * Montgomery-Åsberg Depression Rating Scale (MADRS) score \>6 and \<35 (corresponding to mild-to-moderate depression), assessed during the routine clinical visit with the treating physician. * No evidence of suicidal ideation, high-risk behaviors, history of suicide attempt, or overt psychotic symptoms that could compromise participant safety. * No severe medical condition or unstable physiological state cons…