SS20 was diagnosed at 7 with bipolar. It was really Autism. His mom is bipolar which is why they made that diagnosis. There is nothing wrong with doing an evaluation!

Find the Julie Fast books and follow her on Instagram.  She has it herself and is a well respect authority in living and functioning with Bipolar.  She also has advice on the genetics and kids.  

My SD is 24 and bipolar. She was diagnosed at 18 because the doctor would not give that diagnosis to a child whose psyche had not fully developed.

Both her mother and my DH have bipolar as well.

SD was emotionally stunted by age 5. She lacked social skills. Imaginary friends until middle school. I know she was physically abused by her stepfather when she lived with him and her mother. Mom bailed after DH got primary physical custody.

Pathological lying that is still ongoing . Cruelty to animals and humans. Lack of remorse or pity for others. Stealing. Destruction of other people's things. Self injury. Suicidal ideation. Attention seeking behavior. Inappropriate actions and activities with grown men at age 15. 

She is not medicated or seeing a mental health provider at the present time. 

She was Baker acted multiple times. We sent her to a residential treatment facility and it was worse than before.

My daughter is bipolar 2. There were some things in her teenage years that looking back make sense but I didn't realize it at the time. She was very anxious, had these episodes where she would cry- a lot and was very detached from things. And then she was fine for a while, energetic- her peppy self. She went through a period where she hung out with this girl and went on a cocaine binge. Yes. Cocaine. Very scary stuff for a teenager. It was then i had her admitted and the processes of diagnosis began. She's almost 21 now, still struggles a bit but has been on her own since 18 (besides coming home for summers or breaks during college). Now she rents a house with friends in another state. We've talked about her childhood and how more than likely she has PTSD from her emotionally abusive father. Sometimes I doubt her diagnosis, but now it's all about finding the right medication that works for her. In a very depressed state she will want to stay in bed, loses weight, doesn't eat- and on the other end of it she's chipper, almost comedian like, very out going- sometimes doing rash things like spending money she doesn't have, dying her hair, etc. (mania). Bipolar can be tricky because I feel like so many other issues can be mistaken for it- depression, borderline personality (one doc said he thought she had this), anxiety, pts, etc.  

My best advice is to seek a medical opinion if you feel something is off. Some things are "normal" for a child and somethings are not. Sometimes as a parent it's hard to pinpoint what is and isn't. 

Does not show up until the teens or after,  there is no test for bipolar.  But it does run in the family,  passed down.  Supposedly there is new medication for this,   But there normally some other thing that disorder that goes with it. 
Normally this medication makes the person taking it feel funny.  And may stop sexual feelings.  As in intercourses not working .

So they stop the meds for that reason, or feel they don't need it anymore .