A new study has discovered that about 3 percent of people being treated with selective serotonin reuptake inhibitors (SSRIs) have a greater tendency to commit violent crimes.
This effect seems to continue for up to 12 weeks after stopping SSRI treatment, according to researchers at the Karolinska Institutet in Stockholm, Sweden.
“This work shows that SSRI treatment appears to be associated with an increased risk for violent criminality in adults, as well as adolescents, though the risk appears restricted to a small group of individuals,” said first author and doctoral student Tyra Lagerberg from the Department of Medical Epidemiology and Biostatistics at the Karolinska Institutet.
“We don’t claim that SSRIs cause the increased risk we see in our data. It is possible that the disorders that SSRIs are prescribed to treat, such as depression, are driving the association. In that case our findings may mean that SSRIs are unable to fully remove this tendency towards violent crime, which is also a potentially important insight.”
Lagerberg noted the previous work found an association between SSRI use and violence in young individuals, but not in adults.
“Ours is a much bigger study, which allows us to confirm that there is an association in adults as well,” she said.
For the study, researchers examined the records of 785,337 people aged 15 to 60 years who were prescribed an SSRI in Sweden between 2006 and 2013. These patients were followed up for an average of seven years, which included periods when individuals took SSRIs and when they did not.
People in the study were found to have committed 6,306 violent crimes while taking SSRIs, and 25,897 when not taking SSRIs, according to the study’s findings.
After accounting for follow-up time and variables that were associated with the probability of getting SSRI treatment and with the risk for violence, the researchers found that the risk of committing a violent crime was on average 26 percent higher during periods when individuals took SSRIs compared to periods when they did not.
Only a small proportion of individuals in the study went on to commit violent crimes regardless of treatment — less than 3 percent of the people in the study. Due to the rarity of violent crimes, periods of SSRI medication were expected to coincide with only a small increase in the rate of this event, researchers noted.
When they subdivided the study follow-up according to time since the start and end of SSRI treatment, they found that the risk for violent crime was higher throughout treated periods.
The increased risk also persisted for up to 12 weeks after the estimated end of SSRI treatment, after which the risk returned to levels before the start of SSRI treatment.
The researchers showed that the association between SSRI treatment and violent crime existed in young adults, as well as in adults aged up to 60 years (the study did not investigate the association in adults older than 60 years). However, only 2.7 percent of individuals in the study committed violent crimes during the study period, meaning the increased risk applied to a small subgroup of SSRI users, the researchers said.
“Previous studies have shown that depression itself is associated with a three-fold increase in the risk for violent crime, and of course many SSRIs are prescribed for depression,” Lagerberg said. “It may be the underlying depression that causes the association with violent crime, rather than any effect of the SSRI. More work is needed to uncover the causes of this association.”
“Our results suggest there may be a need for clinical awareness of the risk for violence during and possibly after SSRI treatment across age groups,” she said. “However, a large majority of SSRI users, around 97 percent in our sample, will not experience the outcome of violent crime, so our work needs to be understood in this context. Our findings do not affect the vast majority of people taking antidepressants and should not be used as basis for individuals to stop their SSRI treatment, nor for prescribers to withhold treatment from individuals who might benefit from it.”
“Nevertheless, clinicians should be attentive when prescribing SSRIs to individuals with aggressive tendencies,” she said. “More work is necessary to identify what further individual characteristics might give someone a higher risk of committing violent crimes during SSRI treatment, regardless of whether the risk is increased because of the SSRI or because of the underlying disorder that indicates an individual for treatment with these medications.”
The study was published in the peer-reviewed journal European Neuropsychopharmacology.