People may react differently to the same antidepressant. For example, a particular drug may work better — or not as well — for you than for another person. Or you may have more, or fewer, side effects from taking a specific antidepressant than someone else does.
Inherited traits play a role in how antidepressants affect you. If you have a close relative who responded to a particular antidepressant, tell your doctor, because this could be a good drug choice to start.
In some cases, results of special blood tests, where available, may offer clues about how your body may respond to a particular antidepressant. However, other variables can affect your response to medication.
When choosing an antidepressant, your doctor takes into account your symptoms, any health problems, other medications you take and what has worked for you in the past.
Typically, it may take several weeks or longer before an antidepressant is fully effective and for initial side effects to ease up. Your doctor may recommend some dose adjustments or different antidepressants, but with patience, you and your doctor can find a medication that works well for you.