Long-term effects of antidepressants are not fully known, because very few long-term studies have been done on antidepressants. Depression itself is a risk factor for developing some medical conditions—including heart disease, stroke, diabetes, cancer, and dementia—but there are no data suggesting a link between these and antidepressant medications themselves.
The thought of taking a drug that changes your brain chemistry can be scary, but these medications have been in use for over 20 years and are generally considered safe and effective. Living with untreated depression comes with its own risks over the long term, one of which is suicide.
It’s recommended that people on antidepressants get annual blood tests, but no specific monitoring is required for people on most antidepressants as it is for those who take lithium or neuroleptics, common treatments for bipolar disorder. However, blood tests and electrocardiograms are recommended for those taking tricyclic antidepressants such as nortriptyline (Aventyl) and amitriptyline, and blood pressure is monitored closely for people taking venlafaxine (Effexor).
Some people on antidepressants experience unpleasant side effects—such as sexual problems and weight gain—which may stick around for as long as they take that particular medication. If you are troubled by your medication's side effects, talk to your doctor about switching to an alternative.