Whenwas arrested on suspicion of DUI, officers say she seemed "disoriented." Alcohol was quickly ruled out as a factor in the incident.
This summer, the actress checked herself into a facility to treat anxiety and depression. It is not yet known whether those emotional battles played a part in her weekend arrest.
"We don't know whether she had taken the exact proper dosage of whatever it is she got, but then made the mistake of getting in a car and driving. So we don't even know if it's abuse," said TMZ's Harvey Levin.
Saturday, a witness called 911 to report that Locklear was driving erratically. The actress had decided to pull over and was not driving when officers arrived.
According to the National Institute on Drug Abuse, about 20 percent of Americans have used prescription medication for non-medical reasons.
Dr. Charles Sophy, medical director for the Los Angeles County Department of Children and Family Services, calls the problem "significant."
"Most people don't realize how easy it is to get prescription drugs -- you can get them from your family doctor, you can get them online or you can get them on the street," he said. "Mixing these drugs and not knowing what you are doing or what you are treating is a huge poison mixture."
If you are on prescription medication, Dr. Sophy stresses the importance of reading the labels on the pill bottles.
"The pharmacies don't put all those labels on the bottles that you get for no reason. You have to read them. It's very dangerous -- especially when you are combining medicines or if you haven't slept well or eaten well," he said. "There are a lot of factors that go into how the medicine will affect you, your brain and your body. I urge people to take caution, read labels and be very prudent about what you are doing."
And what if you find yourself addicted?
"Most people will not always find themselves addicted - someone else will help them find that or they'll see their life falling apart," he said.
Dr. Sophy says it's important to understand that there's a big link between mental health and the physical addiction - and both sides need to be addressed.
"It's very important that you see it or get help immediately, because
there are always underlying issues. Often there are mental health issues alongside the substance abuse - if the substance was used to self-medicate," he said.
Is it problem more prevalent with the Hollywood-set?
Dr. Sophy treats celebrities and will be the consulting psychiatrist on the upcoming season of VH1's "Celebrity Rehab."
"Often, the celebrities that we've seen on these shows have started out in doctor's offices on prescription drugs…Their lives are upside down and open to everybody. They try to self-medicate and it becomes a very big problem."