SSRI Antidepressant Side Effects

Individuals looking for an effective antidepressant will often opt for a selective serotonin reuptake inhibitor (SSRI). Concerned with tolerability issues, many will look for an SSRI with the least side effects—or more specifically, an SSRI with the least sexual side effects. While such concerns are certainly valid, it is important to keep in mind that the side effects caused by this family of antidepressants usually go away over time.

Considering the pros and cons of SSRI medications should always include consultations with a healthcare provider about more concerning or unusual adverse effects, which are possible but unlikely to occur. With the variety of SSRIs available, individuals have many choices to consider in an effort to find the right fit, while providing information that should later be discussed with a trusted healthcare professional.

Read on to learn about some of the less common side effects of SSRIs in both adults and children.

SSRI Antidepressant Side Effects

Less Common Side Effects of SSRIs in Adults

The most common side effects are likely to be discussed when consulting with healthcare providers. Reviewing less frequently experienced effects can help individuals better understand their treatment options.

SSRI Cardiac Side Effects

SSRIs are less associated with SSRI cardiac side effects than other antidepressant drug classes. Still, SSRIs are linked with some concerning impacts on cardiac health, notably heartbeat irregularities called arrhythmias. Irregular, slow, and elevated heart rates have all been observed more frequently with citalopram than other SSRIs.

An uncommon disorder called prolonged QT interval, an elongated period between the relaxation and contraction phases of a heartbeat, has been known to occur with SSRI use. In rare instances, prolonged QT interval may lead to an unsafe arrhythmia called Torsade de Pointes. These adverse effects are not typically seen in standard therapeutic doses but may be more likely for those on the high end of the range.

Serotonin Syndrome

Serotonin syndrome is an uncommon but potentially serious condition resulting from a buildup of serotonin in the body. This may occur when SSRIs block too much serotonin from being taken up by receptors, leaving an excess amount available in the neural synapse. The combination of SSRIs and MAOIs, for example, is well-known for elevating the risk of serotonin syndrome, though other serotonergic agents such as tricyclic antidepressants or triptan medications used for migraines, may also pose a risk. That said, serotonin symptoms are often mild, and include headaches and dizziness. The syndrome’s relative mildness, though, means it is not always easily detected, making it difficult to know how often this syndrome truly occurs.

Moderate-to-severe cases are far more unlikely to develop and require immediate medical attention. If symptoms are mild, medication discontinuation may be enough for symptoms to resolve, though medical consultation is recommended to determine the severity and any additional treatments needed.

Long-Term SSRI Discontinuation Syndrome

Many patients using SSRIs may experience discomfort if they stop taking their medication abruptly, a condition called antidepressant discontinuation syndrome. This may present with flu-like symptoms, insomnia, nausea, and sensory disturbances. For most individuals, discontinuing SSRI side effects will resolve in a matter of weeks.

In rare instances, some individuals will continue to experience long-term SSRI side effects for a year or more, even after discontinuing their medication. This extended expression of symptoms is not well understood, though it is not due to physical dependence, such as with alcohol or opioids. No established treatment for ongoing discontinuation symptoms is in place, though individuals may find support from loved ones and others experiencing symptoms to be helpful.

Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIAHD)

An uncommon but known side effect of SSRIs is syndrome of inappropriate antidiuretic hormone secretion. Antidiuretic hormone regulates water levels in the body and sodium, and when too much of this hormone is created and released, the body retains excess water. This increased water volume dilutes levels of sodium, another substance responsible for water regulation.

If water retention and swelling become excessive, symptoms such as a headache, confusion, and nausea may develop. This syndrome most often affects individuals over the age of 65 and appears more likely when using fluoxetine. The effects can be prevented or treated by reducing fluid intake, monitoring the balance of water and electrolytes in the blood, and adjusting medication dosage if necessary.

Less Common SSRI Side Effects in Children

Research shows that SSRIs have some efficacy for youth contending with psychiatric disorders. However, the potential for side effects can raise uncertainties for parents and healthcare providers considering treatments.

When starting SSRIs, children are carefully monitored at the beginning of treatment, starting with weekly appointments for the first month and eventually transitioning to monthly appointments thereafter. Many common side effects are mild and temporary, though studies show that in some instances, children may respond to medication differently from adults. Review these less common adverse effects and consult your primary healthcare provider if you have any related concerns.


While research supports the efficacy of antidepressants in children and teens, some studies show an association for increased suicidality. This adverse effect is understandably concerning, though the increased rate of suicidality appears quite small. This connection does not establish causality for the short-term rise in suicidal thoughts and ideation, suggesting that multiple factors may contribute to this adverse effect.

The current body of research on SSRIs suggests that increased suicidality in youth is a low frequency event. Discussion of individual risk, support, and watchfulness can help parents and healthcare providers be alert to potential harms.

Behavior Activation and Mania Symptoms

Significant mood switches are a possible outcome for children and adolescents using SSRIs. But they are far less likely to occur than mild hypomania symptoms, such as excessive talking or inflated self-esteem.

Mania symptoms are part of a broader, more common category of medication reactions called behavior activation. About 5% of children and adolescents may show agitation, irritability, and increased impulsivity during the first two-to-three weeks of taking SSRIs. While 5% is not an insignificant rate of risk, mild short-term symptoms are most typical and often dissipate when the dosage is reduced or medication is stopped.

Consultation with a healthcare provider is recommended if these symptoms emerge, especially for children and adolescents with risk factors for bipolar disorder. Starting SSRIs slowly with a low dose may help limit behavior activation and help determine whether manic symptoms may be present.

SSRI with least side effects

Considering SSRI Side Effects

When deciding on a treatment course, learning about the most common side effects of SSRIs is essential. Increased awareness of less frequently occurring effects, in addition to consulting a licensed mental health practitioner, enhances one’s understanding of the benefits and risks of antidepressants, a valuable step when making treatment decisions.