I recently had a bad experience with buspar. It was added to my medication regimen to help with the anxiety issues associate with my bipolar and PTSD.
I was started on a low dose which was increased incrementally. I did fine for the first two weeks which brought me to one pill twice a day. I continued to take as prescribed which increased the dose to 2 pills twice a day.
By the time I reached the "therapeutic" dose the side effects were unmanageable for me. I could not think of common words, for example, I knew one of my dogs was black and white but could not think of the word dog when I was trying to talk about him. I did this with many common words. It was not the "tip of the tongue" thing, it was the word was just not there. My thinking was sluggish and cloudy. I isolated even more than normal. I was cycling between deep, suicidal depression and feeling ok. I would cycle through that several times a day. I was ready to call my doc and tell her to admit me to the hospital as I was unsure how long I could go without following through with the suicidal thoughts.
It took a friend suggesting that maybe the problem was the medication increase. I reduced the medication back down to before I had the severe side effect, one twice a day, and have not had problems since.
I do hope that this was more of an untoward effect rather than a common one as I would not want anyone to go through this.