Is it safe to take any antidepressant for decades?

No drug is without: ...some side effect to balance its benefit. That being said, we can more accurately address your concern if you share what longstanding antidepressant you question.

If necessary: one can safely take an antidepressant for many years. That said, be sure to see prescribing doctor regularly to assess need for antidepressant. Good to consider lower dose at times. Keep annual physical exams with your pcp including routine blood work, ECG and let all doctors know of any changes in meds you take. Any change in health status should be shared with prescribing doctor.