Inexpensive and widely accessible, could vitamin B9 play a role in suicide prevention? An American study published in JAMA Psychiatry in 2022 had associated its prescription with a 44% reduction in suicide attempts and intentional self-harm. But a new Swedish analysis, presented at the congress of the European College of Neuropsychopharmacology (ECNP), in Munich, provides contrasting results. A reminder that a promising avenue does not yet constitute a proven treatment.
Among young men, results that raise questions
The team of Professor Jussi Jokinen, from Karolinska Institutet and Umeå University, analyzed data from 21 Swedish regions. Its objective: to study the link between the delivery of folic acid and deaths by suicide among 20-29 year olds.
The analysis focused on 3,463 deaths by suicide. Result: among men aged 20 to 24, the regions where the delivery of vitamin B9 was the greatest had more deaths. Among men aged 25 to 29, the association was inverse, with fewer deaths. No association was observed in women.
Should we conclude that this vitamin increases the risk in younger people? Absolutely not. “Our results should not be interpreted as evidence that folic acid increases the risk of suicide.”underlines Jussi Jokinen.
The study compares regional data, without individually tracking people who received vitamin B9. It therefore does not make it possible to establish a cause and effect link. Another possible explanation: folic acid can be prescribed in medical or psychiatric contexts which themselves influence suicidal risk.
These results therefore prove neither a protective effect nor an aggravating effect. Above all, they invite further research.
In 2022, a drop of 44% had raised hopes
To understand the interest of this avenue, return to the American study published in JAMA Psychiatry on September 28, 2022. The team of Robert Gibbons, professor at the University of Chicago, studied health insurance data from 866,586 patients over two years. Periods covered by a folic acid prescription were associated with a 44% reduction in suicide attempts and intentional self-harm.
The researchers also found that each additional month of prescription was associated with a 5% decrease in the risk of suicide attempt. To limit bias, they compared the patients to themselves before and after the prescription. They also used vitamin B12 as a control: this was not associated with a reduction in risk.
“There are no real side effects, the cost is affordable and the drug is available without a prescription.”declared Robert Gibbons, cited by the University of Chicago.
These results were encouraging, but they were based on an observational study. They do not demonstrate that folic acid is directly responsible for the drop observed.
Can vitamin B9 really prevent suicide?
Folic acid is the synthetic form of vitamin B9. Essential to the functioning of the body, this vitamin is involved in particular in the synthesis of DNA and in biological processes linked to the production of certain neurotransmitters.
This role has led researchers to explore a possible link with mental health. But suicide is a complex phenomenon, influenced by multiple psychological, psychiatric and social factors. A plausible biological explanation is therefore not enough to demonstrate the effectiveness of a treatment.
The two studies do not measure the same thing: the American study focuses on attempts and self-harm among patients who have received a prescription, while the Swedish analysis examines deaths by suicide on a regional scale. Their results are therefore not directly comparable.
To decide, the American team is preparing a randomized controlled trial comparing a group receiving folic acid to a group taking a placebo. Researchers will thus be able to better determine whether the vitamin really has an effect on suicidal thoughts, attempts and acts.
In the meantime, no supplementation can be recommended as a suicide preventive treatment based on these observations alone. As Jussi Jokinen reminds us: “These results should not lead to changes in the clinical use of folic acid.”.
This avenue deserves to be studied, but it must not make us forget the essential: faced with psychological distress or a suicidal risk, rapid access to appropriate help remains essential.