Strokes linked to antidepressant use
According to a new study, antidepressants increase the risk of a hemorrhagic stroke. A hemorrhagic stroke is one due to a hemorrhage from a blood vessel in the brain rather than blockage of blood vessel (occlusive stroke). Researchers affiliated with Western University (London, Canada) published their findings online on October 17 in the Journal Neurology.
The researchers evaluated hemorrhagic stroke risk among individuals taking a common type of antidepressant: selective serotonin reuptake inhibitors (SSRIs). Examples of SSRIs are Lexapro, Paxil, Prozac, and Zoloft. They conducted a meta-analysis, which is the compilation of data from several studies on a specific topic to clarify the validity of the findings. Previous studies have reported an association between the use of SSRIs, and major bleeding, such as gastrointestinal bleeding. SSRI’s are thought to inhibit the aggregation, or clumping together, of platelets, which could lead to bleeding. The investigators searched for controlled observational studies comparing SSRI therapy with a control group not receiving SSRIs.
The investigators found that intracranial hemorrhage and intracerebral hemorrhage were related to SSRI exposure. (Intracranial hemorrhage refers to a hemorrhage within the skull while intracerebral hemorrhage refers to hemorrhage within the brain.) In a subset of five studies (three of intracranial hemorrhage and one each reporting hemorrhagic stroke and intracerebral hemorrhage), SSRI exposure in combination with oral anticoagulants was associated with an increased risk of bleeding compared with oral anticoagulants alone. Examples of oral anticoagulants are Coumadin and Plavix. In the absence of SSRI use, oral anticoagulants are associated with a risk of hemorrhagic stroke. When all studies were analyzed together, increased risk was seen across cohort studies, case-control studies, and case-crossover studies (OR 4.24, 95% CI 1.95–9.24).
The authors concluded that SSRI exposure is associated with an increased risk of intracerebral and intracranial hemorrhage; however, given the rarity of this event, absolute risks are likely to be very low.
SSRIs are the most commonly prescribed antidepressants. They can reduce symptoms of moderate to severe depression, are relatively safe, and generally cause fewer side effects than other types of antidepressants. SSRIs are called selective because they seem to primarily affect serotonin, not other neurotransmitters. They reduce depression by affecting chemical messengers (neurotransmitters) used to communicate between brain cells. Most antidepressants work by changing the levels of one or more of these naturally occurring brain chemicals. SSRIs block the reabsorption (reuptake) of the neurotransmitter serotonin in the brain. Changing the balance of serotonin appears to aid brain cells in the transmission and receipt of chemical messages, which in turn boosts mood.
Take home message:
This study notes that the overall risk of a stroke is low if one takes an antidepressant; however, since the risk exists, these medications should be limited to individuals who have not benefit from non-pharmacologic methods of stress relief such as meditation and counseling. Individuals taking anticoagulants should exercise additional caution regarding taking a SSRI because of the combined risk.