As someone who is bipolar and is prescribed meds by a psychiatrist, I can attest to this. My lithium keeps me from having serious lows, but the caveat is that it can also push me into a manic episode, so I am also on asenapine (an antipsychotic) to control my mania. Basically my brain chemistry is a constant match of tug of war between two prescribed chemicals. It usually works out ok and keeps me in a slightly more balanced mental state, but it can also go terribly wrong and throw me to one or the other extreme; I also no longer remember what it feels like to be clear headed, or to have any real control over my mood/emotions (I can't help but feel like waking up every morning is a complete roll of the dice). So it goes.