Treating Depression on a Day-to-day Basis: Development of a Tool for Physicians Based on a Smartphone Application

This trial is developing and testing a smartphone app that helps doctors track how a depressed patient's mood changes day by day during antidepressant treatment, making it easier to adjust medications quickly and improve treatment outcomes. **You may be eligible if...** - You are between 18 and 65 years old - You have been diagnosed with depression based on DSM-IV clinical criteria - You started antidepressant treatment less than 5 days before enrolling - You are being treated as an outpatient (not hospitalized) - You have been informed of your diagnosis and have given written consent - You own or can use a smartphone **You may NOT be eligible if...** - You have bipolar disorder or psychosis alongside depression - You have a history of alcohol or drug dependency - You have a serious physical illness or cognitive impairment that would interfere with app use - You are currently hospitalized for depression - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.