Yes and they are terrible.
Yes , they can be, but usually its because not everyones chemical balance is the same. Its a matter of finding a good trust with the right medical doctors, therapy and being aware of your triggers.
Ive had some meds that have made things worse, some that make me real tired, twitch , get uncontrollable arm and body movements etc. I hated when I tried one that made me flail my arms and neck so much that I got whiplash. Some that made me gain 40lbs in a matter of a few months. I recently had one that made me feel really good for about 48 hours, then I got extremely angry and aggressive.
If a doctor that wont let you communicate any adverse effects, or dismisses those symptoms, then you tell them and then change doctor. Ive had them tell me to take sedatives so I can drive because they did not believe how drowsy they made me. I had to tell them that there was no way that I could in good conscious get behind the wheel under that influence till I came in after I took it. My mother drove me and helped me in the office and he finally believed me. I tried to do the old fashioned sobriety tests like cops make you do and when I almost fell on my face and off the chair, I said now would you want me behind the wheel if your child was on the road? He rolled his eyes and then I said, well maybe I should and if I kill someone or myself my family and theirs will sue you.
In some cases, like my brother who is schizo effective ( schizo and bi-polar and delusional ) there is no balance, which is very sad. He was a brilliant photographer and artist, but now that he finally trusts us and his doctors he is no longer able to do any of that. He has no middle ground, its either no sleep, delusions, anger aggression and going off from one county to another on foot, finding complete strangers in his home doing very dangerous things.
If you dont do something to get help, you might get really ill or hurt yourself.