Approximately 18% of Australian adults are prescribed antidepressants, making them among the most commonly dispensed medications in the country. But new research suggests these medications may come with a serious potential side effect: sudden cardiac death.
For more than 4.8 million Australians living with depression or anxiety, antidepressants can be lifesaving, making these findings particularly concerning. However, experts stress the importance of not taking new research at face value without clinical context.
Here’s what the study found, plus why it’s not recommended that you suddenly stop taking your antidepressant medication based on this.
What did the study find?
The study has not yet been published, but was presented at the 2025 Congress of the European Heart Rhythm Association, part of the European Society of Cardiology. Researchers analysed death certificate and autopsy data from Denmark in 2010, focusing on individuals aged between 18 and 90.
They categorised deaths as either due to sudden cardiac death (SCD)—an unexpected death likely caused by a heart-related issue—or not due to SCD. The researchers also examined whether individuals had filled a prescription for an antidepressant at least twice in one year during the 12 years leading up to 2010, and how long they had taken the medication. (The study did not differentiate between types of antidepressants.)
They found that people who had filled antidepressant prescriptions for one to five years faced a 56% higher risk of sudden cardiac death compared to those in the general population who did not take the medication. Those who had taken antidepressants for six years or more had a 2.2 times higher risk.
The risk varied by age and length of use, with those taking antidepressants long-term facing the greatest risk. In some cases, the risk of sudden cardiac death increased by as much as five times.
Why might there be a link between antidepressants and sudden cardiac death?
The exact reason for the connection is not clear. The study explored an association between antidepressant use and sudden cardiac death but did not investigate the cause behind it. It’s also important to note that the findings do not prove that taking antidepressants increases the risk of sudden cardiac death—it only suggests a potential link. Additionally, the researchers did not confirm whether participants took their medications as prescribed, using prescription data as a proxy for usage.
There are several theories as to why this link may exist. Some antidepressants are known to raise the risk of developing an abnormal heart rhythm (arrhythmia), which could increase the chances of sudden cardiac events, says interventional cardiologist Dr Cheng-Han Chen. “However, depression itself is a recognised risk factor for cardiac issues, so it may be that antidepressants are simply an indicator of underlying mental health challenges,” he adds.
It’s also possible that individuals taking antidepressants over longer periods are managing more severe or chronic conditions, or have lifestyle or behavioural patterns associated with depression—such as reduced health-seeking behaviour or lower levels of physical activity—that may contribute to poorer cardiovascular health, notes pharmacologist Dr Jamie Alan.
Certain antidepressants, such as selective serotonin reuptake inhibitors (SSRIs), may also interact with medications used for treating heart conditions. These interactions can potentially reduce the effectiveness of some treatments or increase the risk of arrhythmias, explains clinical pharmacist Dr Daniel Abazia. “SSRIs can also interact with medicines like some antibiotics or psychiatric medications and increase the risk of heart rhythm disturbances that may lead to sudden cardiac death,” he says.
Other studies have explored this link with mixed results. One earlier analysis of prescription claims data found that the antidepressant mirtazapine was associated with a higher risk of sudden cardiac death compared to paroxetine. Conversely, a 2021 meta-analysis of data from over 355,000 people reported only a low risk of sudden cardiac death among antidepressant users. Another 2022 review of six studies involving more than 2.6 million participants found that while antidepressants were linked to a higher risk of atrial fibrillation, there was no significant difference in rates of sudden cardiac death between users and non-users.
Crucially, untreated depression itself is known to more than double the risk of cardiac arrest. So while the data highlights a potential connection, it reinforces the need for more targeted research to provide definitive conclusions.
How concerned should people on these medications be?
If you’re currently taking an antidepressant, there’s no need to panic. Study co-author Jasmin Mujkanovic noted that “the increased risk is most likely multifactorial” and emphasised the importance of taking a more holistic approach to managing both mental health and cardiovascular health in these patients.
“At this stage, all we know is that there’s an association,” says Dr Alan.
Dr Chen agrees, adding that in many cases, clinicians perform baseline cardiac testing before prescribing antidepressants to ensure the heart is functioning well prior to starting the medication.
What to do if you take antidepressants
If you’re taking antidepressants and have concerns about your heart health, it’s important to speak with your prescribing doctor or GP. “Don’t stop taking them without medical advice,” says Dr Alan. Abruptly discontinuing antidepressants can cause withdrawal symptoms or the return of depressive symptoms. Some medications require gradual tapering to minimise the risk of side effects.
Dr Abazia agrees, recommending an open discussion with your healthcare provider to evaluate any risks and assess whether further testing is needed.
“Much more research is necessary to fully understand the potential connection between antidepressant use and sudden cardiac death,” adds Dr Chen. “As with all medications, patients should work with their doctor to weigh up the risks and benefits and to explore any available alternatives.”
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