Antidepressants: types and side effects

Antidepressants are medicines that treat depression and are also widely used for anxiety, panic disorder, PTSD and OCD. The most common types, SSRIs and SNRIs, adjust brain chemicals involved in mood. They usually take four to eight weeks to reach their full effect, they aren't addictive, and most people find one that works for them, sometimes after trying more than one.

What are the types of antidepressants?

• SSRIs (selective serotonin reuptake inhibitors): the most prescribed. Examples: sertraline (Zoloft), escitalopram (Lexapro), fluoxetine (Prozac), citalopram (Celexa) and paroxetine (Paxil).
• SNRIs (serotonin and norepinephrine reuptake inhibitors): examples include venlafaxine (Effexor XR), duloxetine (Cymbalta) and desvenlafaxine (Pristiq). Sometimes also used for nerve pain.
• Bupropion (Wellbutrin): works on dopamine and norepinephrine. It's less likely to cause sexual side effects or weight gain, and is also used to help people quit smoking.
• Mirtazapine (Remeron): can help with sleep and appetite, which makes it useful for some people and less suited to others.
• Older types: tricyclics and MAOIs work well but have more side effects or diet restrictions, so they're usually used when newer medicines haven't helped.

What do antidepressants treat?

Depression is the main use, and many antidepressants are also first-choice treatments for generalized anxiety, panic disorder, social anxiety, PTSD and OCD. The free depression self-check and anxiety self-check can help you see how much those symptoms are affecting you.

For moderate to severe depression, combining medication with therapy tends to work better than either alone.

How long do antidepressants take to work?

Some people notice better sleep, energy or appetite within one to two weeks, but the full effect on mood usually takes four to eight weeks. If you've had little improvement after that, your prescriber may raise the dose or try a different medicine. It's common to need more than one try.

Once you feel better, clinicians usually recommend staying on the medicine for at least six to twelve months to lower the chance of depression coming back.

SSRI side effects

SSRIs, the most prescribed antidepressants, tend to share the same side effects. They're often strongest in the first couple of weeks and then ease. Common ones include:

• Nausea or upset stomach
• Headache
• Trouble sleeping, or feeling sleepy
• Feeling jittery or restless at first
• Sweating
• Sexual side effects, such as lower desire or difficulty with orgasm
• Weight changes over time with some medicines

If side effects don't fade or are hard to live with, talk to your prescriber; adjusting the dose, the timing or the medicine usually helps.

Side effects of other antidepressants

• SNRIs (such as venlafaxine and duloxetine) have side effects similar to SSRIs, and can also raise blood pressure slightly.
• Bupropion is less likely to cause sexual side effects or weight gain, but can cause trouble sleeping, dry mouth or a jittery feeling. It isn't used in people with seizure disorders or eating disorders.
• Mirtazapine often causes sleepiness and a bigger appetite, which can lead to weight gain.

Important safety points

• Children, teens and young adults under 25 should be watched closely when starting an antidepressant or changing the dose, because of a small increase in suicidal thoughts early in treatment. Tell someone right away if you notice new or worse thoughts of suicide.
• People with bipolar disorder can have a manic episode on an antidepressant alone, so tell your prescriber about any past periods of unusually high mood or energy.
• Some combinations with other medicines and supplements, such as St. John's wort or certain migraine drugs, can cause a rare reaction called serotonin syndrome. Tell your prescriber everything you take.

Can I stop taking antidepressants?

Yes, but not suddenly. Stopping all at once can cause discontinuation symptoms: dizziness, flu-like feelings, irritability, trouble sleeping, or brief "zap" sensations. These aren't signs of addiction, but they can be unpleasant. Your prescriber can lower the dose gradually, usually over several weeks or months.

What are brain zaps?

Brain zaps are brief sensations that feel like a small electric shock or "buzz" in the head, sometimes spreading down the body. Some people notice them when they move their eyes or turn their head. They're one of the most common symptoms of antidepressant discontinuation, which can happen when an SSRI or SNRI is stopped, lowered, or a dose is missed.

• When they happen: usually within a few days of stopping or reducing the dose, and sometimes within hours of a missed dose.
• Which medicines: they're more likely with antidepressants that leave the body quickly, such as paroxetine (Paxil) and venlafaxine (Effexor XR), and less likely with fluoxetine (Prozac), which leaves slowly.
• How long they last: for most people, a few days to a couple of weeks. For some, withdrawal symptoms last for months, especially after stopping suddenly.
• Are they dangerous? They're unpleasant, but they aren't known to cause harm.

What helps most is preventing them: don't stop suddenly, take doses on schedule, and ask your prescriber to lower the dose gradually. If you get brain zaps after stopping or cutting down, tell your prescriber. Going back to the previous dose and then reducing more slowly often helps; don't change your dose without talking to them first.

Who prescribes antidepressants?

Primary care doctors prescribe most antidepressants and are a good place to start. A psychiatrist or psychiatric nurse practitioner is a good choice if your symptoms are severe, if a first medicine hasn't worked, or if you have other conditions. See psychiatrist vs therapist and how to find a psychiatrist.

Do antidepressants cost much?

Most common antidepressants are available as inexpensive generics and are covered by nearly all insurance plans. Without insurance, many generics cost a few dollars to a few tens of dollars a month with pharmacy discount programs. Newer brand-name medicines cost more.