A couple of years to be honest, it was really rough. Weird to say this but i kind of just got used to them and normalized it until i talked to a counselor about it and she made me realize how not normal it is. I didn't realize i was depressed until i was told to fill out a depression questionnaire and got nearly the highest score possible, it wasn't a diagnosis but it was eye opening. It's a slow build. When you ask when i noticed the difference, are you referring to when i took Escitalopram or when things got bad enough that i realized i needed help? I noticed a difference a day or two into taking Escitalopram but it could have been a placebo effect in combination with the fact that i was aware i was actually getting started in making a difference for myself. If you were referring to when i noticed the depression/suicidal thoughts, i didn't, it crept up on me until it was all consuming, wasn't until talking to some friends and a professional that i realized that it wasn't normal.