Intersession Processes in Psychotherapeutic Treatments Using an Ecological Momentary Assessment Approach (ISA-Bell)

This study is looking at what happens between therapy sessions for people receiving psychotherapy for depression — including how their thoughts, emotions, and behaviors change day-to-day. Researchers will use a smartphone app to check in with participants regularly throughout their treatment. **You may be eligible if:** - You have been diagnosed with mild or moderate depression - Your depression score (PHQ-9) is between 5 and 20 - You own a smartphone with internet access - You are starting or continuing psychotherapy **You may NOT be eligible if:** - You have current or past suicidal thoughts or attempts - You have an active addiction or substance use disorder - You have severe depression, dysthymia (long-lasting low-grade depression), or postpartum depression - Depression is not your primary mental health concern - You are planning to start or change antidepressant medication - You have a history of psychosis, bipolar disorder, or personality disorders - You have cognitive or physical difficulties that would prevent you from using a smartphone or attending therapy Talk to your doctor to see if this trial is right for you.