Started taking methylphenidate er 20 mg and it made me feel depressed, but when i take immediate release i don't get that way. why is this happening?

Generic preparation: . Depression is usually a "rebound" symptom that occurs as a stimulant's effect wears off. With a low dose of a generic biphasic delivery system, the immediate release MPH may be wearing off before the delayed-release dose kicks in. Ask your psychiatrist about titrating by 10 mg./week to a maximum of 60 mg./day of the Watson generic or of branded Concerta, if medical necessity can be established.