The risk of suicide or suicide attempts by adults who start taking antidepressants does not seem to vary by the type of medication, a new study finds.

'Clinicians should be vigilant in monitoring after initiating therapy with any antidepressant agent.' — Study's authors

Study author Dr. Sebastian Schneeweiss of Brigham and Women's Hospital and Harvard Medical School and his co-authors aimed to find out whether the risk of suicide is equal across different classes of antidepressants or whether some classes offer safety advantages in adults.

"There was no clinically meaningful difference in risk among individuals taking different classes of medications," the researchers concluded in the May issue of the journal Archives of General Psychiatry.

The researchers analyzed pharmacy and hospital records of 87,543 adults in British Columbia who started taking antidepressants between 1997 and 2005.

During the first year of antidepressant use, 751 people attempted suicide and 104 committed suicide, according to a review of hospital records and death certificates. Most of the suicides and suicide attempts occurred in the first six months after starting treatment.

Support for FDA advice 

The researchers found no clinically meaningful difference in risk among those taking different classes of antidepressants such as:

  • Selective serotonin reuptake inhibitors or SSRIs such as paroxetine hydrochloride (Paxil).
  • Older tricyclic antidepressants such as amitriptyline hydrochloride.
  • Serotonin-norepinephrine reuptake inhibitors, like venlafaxine.
  • Other and newer atypical drugs such as mirtazapine.

"Our finding of equal event rates across antidepressant agents supports the U.S. Food and Drug Administration's decision to treat all antidepressants alike in their advisory," the study's authors concluded.

"Treatment decisions should be based on efficacy, and clinicians should be vigilant in monitoring after initiating therapy with any antidepressant agent."

Other illnesses, changes in treatment and previous suicide attempts were taken into account during the research.

The large size of the study population allowed the researchers to look at a variety of medications. Limitations of the study included underreporting of suicide by coroners and lack of data on suicide attempts by people who were seen in emergency departments and treated and released without being admitted.

But U.S. data suggests that in 70 per cent of such non-fatal cases of self-harm, patients are admitted.

Since the Food and Drug Administration first issued an advisory on potential increased risk in suicidal thoughts and behaviours among children and adolescents taking antidepressants in 2004, analyses have found no increased risk among adult users.