Starting Antidepressants: What to Expect, Week by Week

Starting an antidepressant often comes with a mix of hope and worry. Will it work? Will it change me? What if the side effects are bad? Knowing the usual timeline helps. The first weeks are often the hardest, and they are also the weeks when people are most tempted to give up.

The main types, in plain words#

Antidepressants are grouped into classes by how they act on chemical messengers in the brain. No class is best for everyone. The choice depends on your symptoms, other health conditions, other medicines, and which side effects matter most to you.

• SSRIs (selective serotonin reuptake inhibitors). The most commonly prescribed group. They increase the availability of serotonin, a chemical messenger involved in mood, sleep and anxiety. Usually tried first because they are well studied and generally well tolerated.
• SNRIs (serotonin and norepinephrine reuptake inhibitors). These act on serotonin and norepinephrine. Sometimes chosen when there is also nerve pain, or when an SSRI has not helped.
• Other antidepressants. A mixed group that works in different ways. Bupropion is one example, which tends to be more energizing and less likely to cause sexual side effects. Mirtazapine is another, which tends to help sleep and appetite.
• Older classes. Tricyclics and MAOIs work well for some people but have more side effects and interactions, so they are usually not a first choice.

The timeline, week by week#

Health services such as the NHS describe the same pattern. Antidepressants usually start to have an effect in 1 to 2 weeks, can take up to 8 weeks to work fully, and are usually continued for at least 6 months after you feel better.

Improvement tends to be gradual and uneven. Other people often notice it before you do. Good days start to outnumber bad ones, rather than everything lifting at once.

Common early side effects, and which settle#

Not everyone gets side effects. When they appear, they are often worst in the first one to two weeks and then ease as the body adjusts.

If a side effect is hard to live with, talk to the prescriber rather than putting up with it in silence. There is often a fix.

The warning for people under 25#

In the US, antidepressants carry a boxed warning, often called a black box warning, from the FDA. It was added because studies showed a small increase in suicidal thoughts and behaviors in children, teenagers and young adults under 25 during the first weeks of treatment.

This sounds alarming, so it helps to understand it calmly. The warning does not say antidepressants cause suicide, and it does not say young people should avoid them. Untreated depression carries its own serious risk. The warning means young people, and those close to them, should watch closely in the first weeks and after any dose change. New or worsening dark thoughts, agitation or unusual changes in behavior should be reported to the prescriber at once.

Stopping, and why it is planned#

Antidepressants are not addictive, but the body adapts to them over time. If they are stopped suddenly, many people get discontinuation symptoms. These can include dizziness, brief electric-shock feelings often called brain zaps, flu-like feelings, nausea, irritability, anxiety, vivid dreams and poor sleep.

These symptoms are usually mild and pass within a week or two. For some people they are stronger and last longer. They are more likely with medicines that leave the body quickly.

This is why stopping is always planned with the prescriber. Prescribers usually reduce the dose gradually, at a pace that suits the person and the medicine. Discontinuation symptoms can also be mistaken for depression returning, and the prescriber can help tell the two apart.

Myths worth clearing up#

"I will get addicted." Dependence is not addiction. Addiction involves craving, losing control and needing more for the same effect. Antidepressants do not do this. Dependence, meaning the body adapts and reacts to sudden stopping, is real, and is managed by planning.

"They will change my personality." Most people who respond say they feel more like themselves. Emotional blunting can happen and is worth reporting.

"They are happy pills." Antidepressants do not create happiness in someone who is well. They help lift a mood that is stuck.

"Needing medicine means I am weak." Depression involves changes in how the brain works. Treating it is no more a weakness than treating high blood pressure.

If the first medicine does not help#

This is common, and it does not mean nothing will work. Many people need more than one try to find the right fit.

At a review, the prescriber may look at whether the dose suits you, whether a different medicine or class would fit better, or whether adding therapy makes sense. They will also check things that block recovery, such as poor sleep, heavy drinking, a thyroid problem or ongoing stress. Tracking your mood with a simple score every few weeks makes these reviews clearer. Most people who keep going with their prescriber find something that helps.

Therapy and medicine together#

For moderate to severe depression, therapy plus medicine often works better than either alone. Medicine can lift mood enough to make therapy possible. Therapy, such as cognitive behavioral therapy, builds skills that last after medicine stops. Regular movement, daylight and steady sleep support both.

Alcohol#

Alcohol is a depressant. It worsens mood, sleep and anxiety, often for a day or two after drinking. With some antidepressants it also adds to drowsiness and slows reactions. Many people feel better simply by cutting back. Your prescriber or pharmacist can tell you what applies to your specific medicine.

What to ask your doctor#

• What side effects are most likely with this medicine, and which usually settle?
• When should I expect to notice a difference?
• When will we review how it is going?
• Does it interact with my other medicines, supplements or herbal remedies?
• What should I do if I miss a dose?
• How long will I likely take it, and how would we plan stopping?
• Is therapy available alongside it?

If a question comes up between appointments, a psychiatrist on our team can answer one question in writing within 24 hours for $29.

What I see in clinic#

The most common thing I see is people stopping in week two. The side effects have arrived and the benefit has not. Knowing that order in advance keeps many people going long enough to find out whether the medicine helps. The second is people stopping suddenly once they feel well, then feeling unwell days later and blaming the depression. A planned stop usually avoids both.

When to get help now#

Contact the prescriber the same day for agitation, confusion, fever with shaking or muscle twitching, a sudden surge of energy with little sleep, or a severe rash. Older adults with new confusion or unsteadiness should also be checked promptly.

Thoughts of suicide can feel overwhelming, but they pass, and help works.

• If you might act on thoughts of suicide or self-harm: call your local emergency number now.
• US and Canada: call or text 988, any hour.
• UK and Ireland: Samaritans, 116 123, any hour.
• Anywhere else: findahelpline.com lists free lines by country.

The bottom line#

Expect side effects first and benefit later. Most early side effects settle within a couple of weeks. Give a medicine 6 to 8 weeks before judging it, and expect to continue for 6 to 12 months once you feel well. Plan any stop with the prescriber, and speak up early about side effects or dark thoughts.