The main benefit of coming off antidepressants is a reduction in the adverse (or side) effects they can cause and avoiding the potential long-term health consequences of staying on them.
As with any type of medication, there are risks with both short-term and extended use. Antidepressant medications have a variety of possible adverse effects, many of which show up early in treatment and continue throughout use of the medication. These adverse effects can have significant effects on other body systems and general well-being.
Sometimes when people take antidepressants for long periods, they do not connect adverse effects to the medication – either because they come on slowly, or because they do not recall what they were like before starting the medication (especially in long-term use).
Common adverse effects include:¹ ² ³
Feeling ‘foggy’ (or having difficulty concentrating)
Weight gain
Disrupted sleep
Sexual problems -- difficulty with erection and ejaculation in men (including a lack of ejaculation or altered ejaculation) or reduced or absent sensation and capacity for orgasm in women, etc.
People taking antidepressants often find they become emotionally numb or apathetic; this is sometimes paired with sexual problems or loss of sex drive.
¹ Read, John, and James Williams. 2018. “Adverse Effects of Antidepressants Reported by a Large International Cohort: Emotional Blunting, Suicidality, and Withdrawal Effects.” Current Drug Safety 13 (3): 176–86. http://www.eurekaselect.com/article/90929
² Bet, Pierre M., Jacqueline G. Hugtenburg, Brenda W. J. H. Penninx, and Witte J. G. Hoogendijk. 2013. “Side Effects of Antidepressants during Long-Term Use in a Naturalistic Setting.” European Neuropsychopharmacology: The Journal of the European College of Neuropsychopharmacology 23 (11): 1443–51. https://www.sciencedirect.com/science/article/abs/pii/S0924977X13001454?via%3Dihub
³ Sansone, Randy A., and Lori A. Sansone. 2010. “SSRI-Induced Indifference.” Psychiatry 7 (10): 14–18. https://pubmed.ncbi.nlm.nih.gov/21103140/