Yes this could be related to the lithium. It could be related to your levels so you may want to check that by having blood drawn. Also.it could be a side effect of depression and to be honest with you I am wondering why you are on lithium if you are 21 anyway. I am also curious if you believe you are bipolar. It is an important question to because bipolar is a serious mood disorder and sometimes if a person is not caught at the right time it can be easy to convince them that they have this disorder if the Dr asks the wrong questions. I will try to help discern the truth with you. You can say yes or no if you do or don't truly believe you have this disorder. After you are sure explain what you experience that convinces you that you are bipolar and that will tell how much the drs told you or you know about what your experience reveals.