Children and young adults who start antidepressant therapy at high doses, rather than the average or typical prescribed doses, appear to be at greater risk for suicidal behaviour during the first 90 days of treatment, a new study has warned.
A previous meta-analysis by the US Food and Drug Administration (FDA) of antidepressant trials suggested that children who received antidepressants had twice the rate of suicidal ideation and behaviour than children who were given a placebo.
The authors of the new study, published in the journal JAMA Internal Medicine, sought to examine suicidal behaviour and antidepressant dose, and whether risk depended on a patient's age.
The study used data from 162,625 people (between the ages of 10 to 64 years) with depression who started antidepressant treatment with a selective serotonin reuptake inhibitor at modal (the most prescribed doses on average) or at higher than modal doses from 1998 through 2010.
The rate of suicidal behaviour (deliberate self-harm or DSH) among children and adults (24 years or younger) who started antidepressant therapy at high doses was about twice as high compared with a matched group of patients who received generally prescribed doses.
The authors suggest this corresponds to about one additional event of DSH for every 150 patients treated with high-dose therapy.
For adults 25 to 64 years old, the difference in risk for suicidal behaviour was null.
The study does not address why higher doses might lead to higher suicide risk, researchers said.
