The fuller answer
Adolescence changes sleep, social pressure, independence, body image, school expectations, family relationships, and the brain at the same time. Hormones can influence emotional intensity, but feelings are never “fake” because hormones are involved.
Embarrassment, irritability, sensitivity, excitement, grief, and wanting more privacy can all increase. The same person may want independence and reassurance in the same hour.
Persistent hopelessness, panic, rage, self-harm, severe withdrawal, inability to function, or thoughts of dying are not something to dismiss as ordinary mood swings. Connection and professional care can help.