Antidepressant medication can instigate young people to commit violent crimes, however higher doses of the same drug appears to reduce that risk, said a new study.
In research published in the PLOS Medicine
journal, the scientists said that while their finding of a link does not prove that such drugs cause people to be more violent, further studies should be conducted and extra warnings may be needed in future when they are prescribed to people aged 15 to 24.
Selective serotonin reuptake inhibitors (SSRIs) - which include drugs like
Prozac - are a common type of antidepressant. SSRIs are usually the first choice medication for depression because they generally have fewer side effects than most other types of antidepressant.
The research led by Prof. Seena Fazel of Britain's Oxford University used a unique study design which aimed to avoid confounding factors by comparing the same individuals' behavior while they were on and while they were off medication.
"The point of the design is that we're comparing people with themselves," said Fazel, adding that this helped minimize the impact of genetics or lifestyle factors.
Scientists conducting the new study used data from Swedish drug prescription and crime registries to compare conviction rates of around 850,000 individuals when they were on and off SSRI medication over a four-year period.
The findings, published in Public Library of Science Medicine, showed that, overall, taking SSRIs increased the likelihood of a violent conviction by 19%.
The results also found a higher risk of young people being involved in violent arrests, non-violent convictions and arrests, non-fatal injuries and having alcohol problems when they were taking the antidepressants - but also that those who took lower doses had a higher risk of being violent.
Fazel stressed that the findings raised several questions and should be investigated further before any changes were recommended on prescribing SSRIs. He added, "The risk increase we report in young people is not
insignificant, and hence warrants further examination. If our findings related to young people are validated in other designs, samples, and settings, warnings about an increased risk of violent behaviours while being treated with SSRIs may be needed."