Lexapro (escitalopram) is prescribed for two conditions: major depressive disorder and generalized anxiety disorder. These are its only FDA-approved uses, though doctors frequently prescribe it off-label for a wider range of mental health conditions. It belongs to a class of medications called selective serotonin reuptake inhibitors, or SSRIs, and is one of the most commonly prescribed antidepressants in the United States.
FDA-Approved Uses
Lexapro has two official indications. The first is major depressive disorder (MDD) in adults and adolescents aged 12 to 17. The second is generalized anxiety disorder (GAD) in adults only. For anxiety, it has not been approved for anyone under 18.
For depression, the approval covers both short-term treatment of active episodes and longer-term maintenance therapy to prevent relapse. For generalized anxiety disorder, the approval covers acute treatment, meaning it’s intended to bring symptoms under control rather than being studied specifically as a years-long maintenance medication for anxiety (though many people do stay on it long-term in practice).
Common Off-Label Uses
Many prescriptions for Lexapro fall outside these two approved conditions. “Off-label” means a doctor is using their clinical judgment to prescribe a medication for something the FDA hasn’t formally reviewed it for. This is legal and common across medicine.
According to the National Alliance on Mental Illness (NAMI), Lexapro is frequently prescribed off-label for obsessive-compulsive disorder (OCD), panic disorder, post-traumatic stress disorder (PTSD), social phobia, body dysmorphic disorder, eating disorders like binge eating disorder and bulimia nervosa, premenstrual dysphoric disorder (PMDD), premature ejaculation, and hot flashes associated with menopause. The evidence supporting these uses varies, but many clinicians consider Lexapro a reasonable option for anxiety-related and mood-related conditions beyond its two approved indications.
How Lexapro Works
Your brain uses serotonin as a chemical messenger between nerve cells. After serotonin delivers its signal, a protein called the serotonin transporter pulls it back into the nerve cell for recycling. Lexapro blocks that transporter, leaving more serotonin available in the gaps between nerve cells. This strengthens serotonin signaling over time.
What makes Lexapro somewhat unique among SSRIs is that it binds to the serotonin transporter in two places simultaneously. The second binding site reinforces the first, making the drug hold on longer and block serotonin reuptake more effectively. This dual-binding mechanism is one reason Lexapro can work at relatively low doses.
Lexapro vs. Celexa
Lexapro is closely related to an older antidepressant called Celexa (citalopram). Celexa, approved in 1998, contains a 50/50 mixture of two mirror-image molecules. Only one of those molecules, the “S” version, is responsible for the antidepressant effect. Lexapro, approved in 2002, contains only that active molecule, stripped of its inactive counterpart.
This matters in a few practical ways. Lexapro’s effective dose is roughly half that of Celexa: 10 mg of Lexapro does the work of 20 mg of Celexa. Lexapro also doesn’t block histamine receptors the way Celexa mildly does, which can translate to less sedation or weight-related side effects for some people. Celexa carries a stronger warning about heart rhythm changes at higher doses. The FDA recommends against using Celexa above 40 mg per day, while Lexapro’s maximum is 20 mg. Notably, Celexa is only approved for depression, while Lexapro has the additional approval for generalized anxiety disorder.
Typical Dosing
For both depression and anxiety in adults, the standard starting dose is 10 mg once daily. Many people stay at 10 mg because clinical trials showed that bumping up to 20 mg didn’t consistently produce a greater benefit for depression. If an increase is needed, it typically happens after at least one week.
For adolescents (ages 12 to 17) being treated for depression, the starting dose is also 10 mg once daily, but any increase to 20 mg should wait at least three weeks rather than one. The maximum dose for all age groups is 20 mg per day.
How Long It Takes to Work
Lexapro raises serotonin levels within hours of the first dose, but you won’t feel a meaningful difference that quickly. The brain needs time to adapt to the new chemical environment. Early signs that the medication is working, like improved sleep, more energy, or a return of appetite, can appear within one to two weeks.
The core symptoms people take Lexapro for, such as persistent low mood, loss of interest in activities, or chronic worry, typically take longer. Full improvement often takes six to eight weeks. This is why doctors generally recommend giving the medication a fair trial before deciding it isn’t working. Once you’re taking it daily, the drug reaches stable levels in your bloodstream within about a week, thanks to a half-life of roughly 27 to 32 hours.
How Effective Is It?
No antidepressant works for everyone, but Lexapro has solid clinical trial data behind it. In a controlled trial for generalized anxiety disorder, 68% of people who completed the study on Lexapro were classified as responders at eight weeks, compared to 41% on placebo. That gap of about 27 percentage points represents the effect attributable to the medication itself, beyond what improvement would have happened naturally or from the placebo effect.
For depression, clinical trials demonstrated effectiveness at both 10 mg and 20 mg. Lexapro is generally considered one of the better-tolerated SSRIs, which is part of why it’s so widely prescribed. A medication that works moderately well but that people can actually stay on long enough to benefit from is often more useful in practice than one with slightly higher efficacy but more side effects.
Important Safety Considerations
All antidepressants, including Lexapro, carry an FDA boxed warning about an increased risk of suicidal thoughts and behavior in children, adolescents, and young adults under 25 during the early weeks of treatment or after dose changes. This doesn’t mean the medication causes suicidal behavior in most people. It means close monitoring matters, especially in the first few months. For adults over 25, clinical trial data did not show this increased risk, and for adults over 65, antidepressants were actually associated with reduced suicidal thinking.
Lexapro should not be taken with MAO inhibitors, a different class of antidepressant, due to the risk of a dangerous reaction called serotonin syndrome. This condition involves dangerously high serotonin levels and can cause rapid heart rate, high blood pressure, fever, and muscle rigidity. Combining Lexapro with other medications that raise serotonin, including some migraine drugs and certain supplements like St. John’s Wort, also increases this risk.