Antidepressants and suicide risk in depression
Authors: Philppe Courtet, Jorge Lopez‐Castroman
Journal: World Psychiatry (2017)

The last years have witnessed a controversy about antidepressant use that is still in the balance. On one side, treating depression with antidepressants seems to reduce the risk of suicide at an epidemiological level1. This is in accord with the high population attributable risk for a first occurrence of suicidal ideation and suicide attempts in people with mood disorders, which has been estimated at 51% and 44% respectively2, and with the finding of a history of depressive episodes in most completed suicides (approximately 60%). On the other, the possible emergence or worsening of suicide risk at the beginning of treatment, at least among the young, has led regulatory bodies to issue specific warnings. Antidepressant prescriptions fell as an effect of these warnings, also in adult populations, and research about the suicidal effect of antidepressants was fostered. Doubts about the usefulness of antidepressants in the treatment of depressed patients who are or become suicidal need an urgent response. The controversy began in 2003, when re-analyses of data from randomized controlled trials (RCTs) found that the risk of suicidal ideation or suicidal attempts among youth treated with antidepressants was doubled compared with those treated with placebo (4% vs. 2%), independently of the indication (see Brent3 for a review). Later, a meta-analysis of RCTs across the life span reported an increased risk of "suicidality" with antidepressants under the age of 25 years. Of note, this risk was found only in patients with psychiatric indications other than depression, while antidepressants showed a protective effect in depressed elderly subjects4. Reporting about suicidal events in RCTs, most of which are not aimed at examining suicidality, is limited by important shortcomings. Anyway, the warnings – amplified by the alarming media coverage – led many physicians to decrease antidepressant prescriptions, even when no alternative was available5. The use of antidepressants to prevent suicidal behaviour is supported by several facts. First, most pharmacoepidemiologic studies, which are more representative of patient populations than RCTs, show a protective effect of antidepressant use with respect to suicide1. Second, although observational studies suggest an increased risk of suicidal ideation or suicide among young people receiving antidepressants, antidepressants actually seem to reduce the risk when confounding by indication is accounted for3. Third, post-mortem studies with toxicological detection of antidepressants indicate that suicides in depressed patients occur more often among those who are not taking an antidepressant1. Furthermore, treatment-related suicidal events can be minimized. The guidelines produced by the US Food and Drug Administration and the UK National Institute for Health and Care Excellence recommend a closer monitoring of antidepressant treatment in suicidal patients or those younger than 30 years, with a follow-up visit one week after the start of a new antidepressant. Web-based tools and smartphone apps may help in the near future to improve the monitoring of patients at risk. On the other hand, depressed patients are frequently non-adherent to treatment, which has made some authors wonder if antidepressants have actually any effect, positive or negative, on suicide rates at the level of the general population6. This controversial context has also fostered research, but only some observational studies have investigated the predictors of de novo suicidal behaviour in depressed patients starting an antidepressant5, 7. In general terms, treatment-emergent suicidal ideation is infrequent in adults and tends to disappear progressively in the first 4-6 weeks of treatment. The lack of response to treatment, a history of previous suicide attempts and a history of substance use disorders are the best predictors of the emergence of new suicidal ideation or attempts. Of note, starting treatment with high doses of antidepressants (beyond the recommendations) seem to increase the risk of suicidal ideation or attempts5. Suicidal events at the onset of antidepressant treatment may also be associated with an undiagnosed bipolar disorder, whose presence may be suggested by early onset of depression and atypical depressive episodes. Moreover, the age effect in treatment-emergent suicidal ideation or attempts is probably influenced by the more frequent association of substance abuse and impulsive aggression with depression in the youth. All these findings sum up to the general need of a paradigm shift in the treatment of suicidal patients. The clinical response to antidepressant treatment is poorer in subjects presenting suicidal ideation or a history of suicide attempts, independently of clinical confounders or the type of antidepressant7. Those who are most in need of an efficient treatment respond less well. The current development of RCTs designed for depressed patients at risk for suicide will help to refine short-term treatment strategies for these patients. Some potential treatments for suicidal patients deserve to be investigated in depth: first, the combination of lithium or antipsychotics with antidepressants; second, the nearly immediate and dramatic anti-suicidal effect of low doses of ketamine. This latter effect is particularly intriguing and might be explained by an impact on glutamatergic neurotransmission, particularly in the anterior cingulate cortex5. There is also mounting evidence on the role of social, psychological and physical pain in suicidal behaviour. The μ-opioid receptor system is involved not only in physical pain but also in the modulation of social pain, and represents a relevant target for suicide prevention. A four-week study in patients with elevated suicidal ideation showed that an ultra-low dose of sublingual buprenorphine was more effective than placebo in the reduction of that ideation8. A call for caution is finally needed regarding the current risk of psychiatric patients to undergo physician-assisted suicide. Legalized physician-assisted suicide should not be a manifestation of therapeutic nihilism9. It is ethically mandatory that evidence-based treatments and available anti-suicidal strategies be implemented whenever a psychiatric condition is present. Philppe Courtet1,2, Jorge López-Castroman2,3 1Department of Emergency Psychiatry and Acute Care, Montpellier University Hospital, Hôpital Lapeyronie, Montpellier, France; 2INSERM Unit 1061, University of Montpellier, Montpellier, France; 3Nimes University Hospital, Nimes, France