Antidepressants are primarily used to manage depression and anxiety-related conditions, helping to stabilize mood, reduce symptoms like fatigue or low motivation, and support daily functioning.
Antidepressants are a class of psychotropic medication used mainly to treat depression.
The different classes vary mainly in their side-effect profile. They differ less in how well they work for a typical first episode of depression.
Common Long-Term Side Effects
A study by Bet et al. (2013) found that tricyclic antidepressants (TCAs) were linked to more side effects than other classes. Reported symptoms included dry mouth and constipation.
For SSRIs, the most prescribed class, common long-term effects included:
- Sexual dysfunction
- Weight gain
- Dry mouth
- Profuse sweating
In a larger study, Cartwright et al. (2016) surveyed patients who had taken antidepressants for 3–15 years. While most felt the medication helped their depression, many also reported:
- Withdrawal symptoms (73.5%)
- Sexual issues (71.8%)
- Weight gain (65.3%)
- Emotional numbness (64.5%)
- Feeling addicted (43%)
Patients expressed a need for more information about long-term risks and support when discontinuing medication.
Physical Health Risks
Long-term use—particularly of medications that affect serotonin—may increase appetite and weight, raising the risk of high blood sugar and type 2 diabetes.
Higher doses of TCAs and SSRIs have been linked to worsened blood sugar control, possibly due to medication-induced weight gain.
Tolerance and Reduced Effectiveness
Some users report that antidepressants become less effective over time.
While the exact cause is unclear, desensitization of brain receptors may play a role. Other contributing factors include:
- Aging
- High stress
- Substance use
- Other mental health conditions
Treatment-Resistant Depression (TRD)
In 10–30% of cases, people may not respond to standard treatment—this is known as treatment-resistant depression.
TRD may stem from misdiagnosis, metabolic issues, or genetic factors, and often requires a combination of medications and therapy.
One newer option for TRD is ketamine or esketamine. Unlike older drugs, they act on the brain’s glutamate system rather than serotonin or noradrenaline, and can ease symptoms within hours rather than weeks.
But they carry real risks. Because of side effects such as dissociation and a recognised misuse risk, both are given only under monitored supervision in specialist clinics rather than through ordinary prescription.
Can antidepressants cause cognitive decline?
Studies on long-term antidepressant use and cognition show mixed findings.
Some studies report no acceleration in cognitive decline versus non-users. One cohort, however, found modest decline associated with SSRIs in older adults, though clinical significance was uncertain (Mo et al., 2025).
On the other hand, clinical evidence suggests some antidepressants may improve cognitive function in depressed individuals.
For example, fluoxetine has been linked to improved memory, attention, and concentration in adults, including the elderly and those recovering from brain injury (Ampuero et al., 2024).
Does Long-Term Use Permanently Change Brain Chemistry?
Researchers do not yet fully understand the neuronal basis of SSRIs’ positive and negative effects. One clue comes from animal research.
Kobayashi, Ikeda and Suzuki (2011) treated adult male mice with fluoxetine, an SSRI, then tracked their behaviour and brain tissue. The mice’s activity became erratic.
Day-to-day activity swung sharply between hyperactivity and inactivity during treatment, and anxiety-like behaviour persisted for up to four weeks after the drug was stopped.
Examining the mice’s brains, the researchers found a reversal of maturation in granule cells. This cell type sits in the hippocampus, the brain region linked to memory.
The researchers suggested that this dematuration of the hippocampus granule cells might be associated with the destabilized behaviors as a result of fluoxetine (Kobayashi, Ikeda, & Suzuki, 2011).
Other research has suggested that antidepressants can activate neuroplasticity in adult human brains, the brain’s ability to form and reorganize synaptic connections.
This has been observed in preliminary studies showing increased neuroplasticity in the visual cortex.
Whether these effects are permanent is unclear. Most researchers consider it unlikely that antidepressants cause permanent changes to brain chemistry in the long term.
The evidence so far suggests these changes persist only while the medication is being taken, or for a few weeks after withdrawal. The effects appear temporary.
Antidepressants may be used short-term for acute symptoms or long-term for chronic or recurring depression.
As prescribing trends shift toward long-term maintenance, more people are taking these medications fo
What Antidepressants Are and How They Work
Most commonly prescribed for major depressive disorder, antidepressants are also used for several anxiety-related conditions, including generalized anxiety, panic disorder, social anxiety, PTSD, and OCD.
Doctors prescribe them for several physical conditions too. These include fibromyalgia, chronic fatigue, diabetic neuropathy, and premenstrual syndrome.
This article is for informational and educational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment.
Always seek the advice of your physician, therapist, or other qualified health provider with any questions about a medical or mental health condition. Never delay seeking professional advice because of something you read on this site.
The mechanism is chemical. Antidepressants work mainly by influencing neurotransmitters, especially serotonin, dopamine, and norepinephrine, which affect mood, motivation, and alertness.
Most are taken once a day. They typically take two to four weeks to start working. They should be stopped gradually rather than suddenly, since abrupt withdrawal can trigger dizziness, tremor, insomnia, and a return of symptoms.
A newer class works differently. Ketamine, and its derivative esketamine, targets the brain’s glutamate system instead of serotonin or noradrenaline, and can ease depressive symptoms within hours rather than weeks.
Dosing is not one-size-fits-all.
Different medications target these brain chemicals in different ways, and the right drug and dose depend on a person’s symptoms and how they respond to treatment.
Some people stay on antidepressants long-term, especially if symptoms return when the medication is stopped. Although these drugs are usually well-tolerated, long-term use raises questions that researchers are only beginning to answer.
Types of Antidepressants (Brief Overview)
There are several classes of antidepressants, each affecting brain chemicals slightly differently. The most common include:
- SSRIs (Selective Serotonin Reuptake Inhibitors):
Often the first-line treatment due to their relatively mild side effects. They increase serotonin availability in the brain and may cause sleep issues, weight gain, or sexual dysfunction. - SNRIs (Serotonin-Norepinephrine Reuptake Inhibitors):
Affect both serotonin and norepinephrine levels. Side effects may include increased blood pressure, nausea, and restlessness. - TCAs (Tricyclic Antidepressants):
Older medications with stronger sedative effects. More likely to cause weight gain, dry mouth, dizziness, and sexual side effects, and their effect on the heart makes an overdose considerably more dangerous than with newer classes. - MAOIs (Monoamine Oxidase Inhibitors):
Block an enzyme that breaks down monoamines — the serotonin and noradrenaline that MAOIs, TCAs, and SSRIs all target. They are rarely prescribed today largely because of the “cheese reaction”: combined with tyramine-rich food (aged cheese, cured meats), they can cause a dangerous spike in blood pressure. Can be effective for treatment-resistant cases.
Each class varies in side effects and tolerability. Treatment plans are tailored to the individual’s symptoms, response, and health profile.
How to manage long-term antidepressant use
Antidepressants, specifically SSRIs, which are considered the most tolerable and are, therefore, the most prescribed, are generally safe to take long-term.
The long-term effects discussed above may only occur for a small number of people, and the medication itself should disclose a list of possible side effects.
Here is how to manage or help prevent these long-term effects:
- Regular check-ins: See your doctor at least twice a year to review whether the dose is still working or needs changing.
- Gradual withdrawal: Only stop under a doctor’s guidance, tapering over several months or longer, to minimize withdrawal symptoms and relapse risk.
- Combine with therapy: Medication often works faster at first, but psychotherapy such as cognitive behavioral therapy (CBT) tends to catch up in effectiveness over months, and combining psychotherapy with medication typically works better than either alone.
- Watch for warning signs: Notice changes early, such as difficulty sleeping, so your dose can be adjusted sooner.
- If treatment-resistant: A doctor may add a second medication, or recommend psychotherapy or electroconvulsive therapy (ECT).
- If it stops working: A doctor may raise the dose, switch medications, add psychotherapy, or suggest lifestyle changes.
- Manage weight and blood sugar: Exercise and dietary changes can help offset weight gain linked to some antidepressants.
Frequently Asked Questions
How long can you be on antidepressants?
The duration of antidepressant use varies depending on individual circumstances. In some cases, people may take antidepressants for several months to a year or longer, while others may require them for shorter periods.
It is important to consult with a healthcare professional to determine the appropriate duration of antidepressant treatment based on the specific needs and progress of the individual.
What happens if you take antidepressants for years?
If someone takes antidepressants for years, it is generally considered safe under medical supervision. Long-term use helps manage chronic or recurrent depression. The benefits of continued use are weighed against potential side effects and individual response.
Regular monitoring, dosage adjustments, and periodic reassessment with a healthcare professional are important to ensure the medication’s ongoing effectiveness and address any concerns that may arise.
Does your brain go back to normal after antidepressants?
After discontinuing antidepressants, the brain typically returns to its normal functioning. However, the exact timeline varies among individuals.
Withdrawal symptoms or a transient adjustment period may occur, but the brain’s neurochemical balance eventually stabilizes. It’s important to work with a healthcare professional to develop a safe and gradual tapering plan to minimize potential discontinuation effects and ensure a smooth transition.
Do you need mental health help?
USA
Contact the National Suicide Prevention Lifeline for support and assistance from a trained counselor. If you or a loved one are in immediate danger: https://suicidepreventionlifeline.org/
1-800-273-8255
UK
Contact the Samaritans for support and assistance from a trained counselor: https://www.samaritans.org/; email jo@samaritans.org .
Available 24 hours a day, 365 days a year (this number is FREE to call):
116-123
Rethink Mental Illness: rethink.org
0300 5000 927
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Key Takeaways
- Not Usually Permanent: Brain changes from antidepressants mostly persist only while the drug is being taken, or for a few weeks after stopping.
- Onset Takes Weeks: Most antidepressants take two to four weeks to start working and should be stopped gradually, never suddenly.
- Side Effects: SSRIs are the most tolerable and most prescribed; older classes like TCAs and MAOIs carry heavier side-effect burdens.
- Treatment-Resistant Cases: Around 10–30% of people do not respond to standard treatment; options include switching medication, adding therapy, or newer drugs like ketamine.
- Evidence Limits: Most antidepressant trials run for only weeks, so genuinely long-term safety evidence comes mainly from smaller observational studies rather than large randomised trials.
- Combine with Therapy: Medication often works faster at first, but combining it with psychotherapy such as CBT typically works better long-term than either alone.
References
Ampuero, E., Luarte, A., Flores, F. S., Soto, A. I., Pino, C., Silva, V., Erlandsen, M., Concha, T., & Wyneken, U. (2024). The multifaceted effects of fluoxetine treatment on cognitive functions. Frontiers in Pharmacology, 15, 1412420. https://doi.org/10.3389/fphar.2024.1412420
Bet, P. M., Hugtenburg, J. G., Penninx, B. W., & Hoogendijk, W. J. (2013). Side effects of antidepressants during long-term use in a naturalistic setting. European Neuropsychopharmacology, 23(11), 1443–1451. https://doi.org/10.1016/j.euroneuro.2013.05.001
Cartwright, C., Gibson, K., Read, J., Cowan, O., & Dehar, T. (2016). Long-term antidepressant use: patient perspectives of benefits and adverse effects. Patient Preference and Adherence, 10, 1401–1407. https://doi.org/10.2147/PPA.S110632
Kobayashi, K., Ikeda, Y., & Suzuki, H. (2011). Behavioral destabilization induced by the selective serotonin reuptake inhibitor fluoxetine. Molecular Brain, 4(1), 12. https://doi.org/10.1186/1756-6606-4-12
Mo, M., Abzhandadze, T., Hoang, M.T. et al. Antidepressant use and cognitive decline in patients with dementia: a national cohort study. BMC Med 23, 82 (2025). https://doi.org/10.1186/s12916-025-03851-3
