Antidepressants (SSRIs): How They Work and What to Expect

7 min read · Medicines · By the Asthra Health Care team

What SSRIs are

SSRIs, or selective serotonin reuptake inhibitors, are the most commonly prescribed group of antidepressants. Examples include fluoxetine, sertraline, escitalopram and paroxetine. They increase the availability of serotonin, a chemical messenger in the brain involved in mood, sleep, appetite and anxiety. SSRIs are used for depression, anxiety disorders, panic disorder, obsessive-compulsive disorder and some other conditions, always only on a doctor's prescription.

Depression is a real illness

Depression is not weakness or laziness. It is a common, treatable medical condition. Symptoms include low mood most of the day, loss of interest in things you enjoyed, tiredness, poor sleep or too much sleep, changes in appetite, difficulty concentrating, feelings of guilt or worthlessness, and sometimes thoughts of self-harm. In many Indian families, these symptoms are dismissed or described only as body pains, headaches or weakness, which delays help.

How treatment usually works

A doctor, often a psychiatrist or a trained general physician, assesses your symptoms and health before deciding whether medicine is needed. Mild depression may be treated with talking therapy, lifestyle changes and support alone. Moderate or severe depression often benefits from a combination of medicine and counselling.

Doctors may order blood tests such as thyroid function, vitamin B12, blood sugar and a blood count, because some physical illnesses can cause or worsen low mood. Your doctor will also ask about alcohol use, sleep, stress at home or work, and any past episodes of low or very high mood.

What to expect when starting

SSRIs do not work instantly. Sleep and energy may improve first, while mood usually takes a few weeks to lift. Some people feel a little more anxious or unsettled in the first days. This is why your doctor will want to see you again soon after starting, and why it is important not to give up early.

Your doctor will decide the medicine, how much to take and how long to continue. Many people need treatment for several months after they feel better, to prevent the depression from returning. Keep all follow-up visits, even when you feel well, so that your progress can be reviewed.

Common side effects

Side effects are usually mild and often ease within the first few weeks as the body adjusts. Tell your doctor about any that bother you, as changing the medicine or timing can help. Do not adjust anything yourself, and never share your antidepressant with anyone else.

• Nausea, stomach upset or loose motions
• Headache, dizziness or feeling restless
• Sleep changes, either drowsiness or difficulty sleeping
• Sweating, dry mouth
• Changes in sexual desire or function
• Increased risk of bleeding, especially with painkillers like NSAIDs or blood thinners

Important safety points

In young people especially, antidepressants can occasionally increase suicidal thoughts in the early weeks. Families should watch for worsening mood, agitation or talk of self-harm and contact the doctor immediately. SSRIs can interact with other medicines, including some migraine medicines, other antidepressants, tramadol and certain herbal products, which can cause a rare but serious reaction called serotonin syndrome. Always tell your doctor and pharmacist about everything you take.

Avoid alcohol, which worsens depression and can increase drowsiness and other side effects. Be careful when driving or using machinery until you know how the medicine affects you. Keep medicines stored safely, especially if anyone at home has had thoughts of self-harm.

Never stop suddenly

SSRIs are not addictive in the way sleeping pills or alcohol can be, but stopping suddenly can cause discontinuation symptoms. These include dizziness, 'electric shock' sensations, irritability, flu-like feelings, vivid dreams and a return of low mood. When it is time to stop, your doctor will plan a gradual reduction. Never stop or restart an antidepressant on your own, even if you feel much better.

Pregnancy, children and older adults

If you are pregnant, planning pregnancy or breastfeeding, discuss it with your doctor rather than stopping medicine suddenly, since both untreated depression and some medicines carry risks. Children and teenagers need specialist care. Older adults may be more prone to low sodium levels, falls and bleeding, so doctors monitor them closely. People with liver disease, epilepsy or bipolar disorder need individual advice. Consult your doctor or pharmacist with any concerns.

This article is general health information, not medical advice. Do not start, stop or combine medicines on your own — always follow your doctor's prescription and ask your pharmacist if unsure.