One of them was the controversial sleeping pill Ambien.
Ambien has been in the negative spotlight before. While officials can't be certain if it played a role in the shooting at Fort Hood, Action News has learned the gunman was taking it for sleep problems.
Ambien and its generic form are one of the most commonly-used drugs with 44 million prescriptions in 2012.
Although reactions such as bizarre behavior are rare, they do happen, and some have been very high profile.
Six weeks ago, Kerry Kennedy, the daughter of late Senator Robert Kennedy, was acquitted of charges related to a car accident she says occurred under the influence of Ambien.
Her cousin Patrick Kennedy had a similar crash in 2006.
Last year, the FDA ordered lower doses, because the drug can cause next-day mental fogginess.
Healthcare officials recommend anyone taking a sleeping pill to follow the directions carefully and report any problems to your doctor.