I thought this was interesting:
FDA Checks Into Singulair Suicide Risk
March 27, 2008 -- The FDA today announced that it is working with the drug company Merck to investigate a possible link between Merck's asthma and allergy drug Singulair and behavior/mood changes, suicidality (suicidal thinking and behavior), and suicide.

The FDA's investigation may take nine months. As of now, there's no proof that Singulair directly affects suicide risk.

Meanwhile, the FDA calls Singulair "effective" and advises patients with questions not to stop taking Singulair before talking to their doctor.

The FDA also asks health care professionals and caregivers to monitor patients taking Singulair for suicidality and changes in behavior and mood.

The FDA notes that over the past year, Merck has updated Singulair's prescribing information and patient information to include the following postmarketing adverse events: tremor (March 2007), depression (April 2007), suicidality (October 2007), and anxiousness (February 2008).