I had an obsessive thought for 3 years (something I was embarrassed about). After my doctor gave me drugs for other problems -- Zyban to stop smoking and Xanax to help me sleep -- the obsessive thoughts went away. Are these medicines responsible? --Phyllis

It very well could be the medicine, although of course I can't say for sure about your specific situation. But you don't mention any other interventions, such as psychotherapy, or any life or behavioral changes that may have contributed to stopping your obsessive thought.

The medication Zyban, which is being marketed as an aid in smoking cessation, is actually a form of the antidepressant bupropion, commonly known as Wellbutrin. The FDA has approved its use in treating nicotine addiction. Xanax (generic name alprazolam), as you may know, is an antianxiety medication. So in taking Zyban and Xanax you're actually taking two medications that are "psychotropic," which means they act upon the mind and are capable of modifying mental activity.

Ruminations and obsessive thinking are found in both anxious and depressed individuals. If your obsessive thought was in some way a feature of anxiety or depression, then the Zyban and Xanax could indeed have had an effect. Obsessive thinking is also found in obsessive-compulsive disorder (OCD), where it's usually accompanied by compulsive behaviors or rituals. Neither bupropion or alprazolam are considered to have anti-obsessional qualities, at least according to my resources on psychotropic medication. But they do, as I mentioned, address depression and anxiety.

It's probably worthwhile to let your physician know of the change in your thinking. You may not have told him or her about your obsessive thought -- some people are reluctant to disclose such thinking even to health professionals out of embarrassment or fear they'll be considered crazy. But this development may help your physician better understand you and factors that could be associated with your sleep disturbance and smoking. That could aid in your continued treatment.