insomnia
"Been using Zolpidem several years now,  1/2 of a 10mg tablet when required. Stayed at that dose for a couple years, until began waking up after 4-5 hours. Began taking just a small pinch more to get back to sleep. Recently I found myself taking 2/3s pill at bedtime, and though I've never had any bizarre behavior on it, have been noting memory and mood changes as I've aged past 70 which I was attributing to normal aging and/or my thyroid disorder.  However, after carelessly downing an entire 10 mg pill last night, I woke this morning feeling very groggy, foggy headed, and my vision was blurry. Sweet dreams."