Young people who start taking antidepressants at higher-than-average doses may be twice as likely to commit suicide, especially in the first three months of treatment, as those who begin treatment with customary doses, according to a new study led by Harvard School of Public Health (HSPH). Earlier studies found that taking selective serotonin reuptake inhibitor antidepressants (SSRIs) increased suicidal thinking and behavior in young people, which prompted the U.S. Food and Drug Administration to issue warnings about the drugs 10 years ago. The new study suggests that it may be the initial dose of such drugs that matters most.