I was asked the question what makes mood symptoms ones of bipolar disorder and normal mood fluctuations. This became a difficult question to answer even after research. There are two areas to look at, one being an teenage stage and the other an adult one. Teenagers all go through more turmoil with emotions that may appear as bipolar to adults and is not always the case and adults are more likely to have been able to hide such emotions outwardly that it's not easily seen by others.
I first revert to the basic symptoms of bipolar disorder and what a couple of this my own Dr has said to me. First is when your own symptoms prevent you from living life then it's some thing you should look into. Another is that when your manic mood, or feeling of excitements is so great you can not pull them back when you desire to. That would be the case if you are so excited and seeing you be this way, you can't get control over your emotions. This would be true in a depressive state as well, if you can't see anything beyond the negative feelings you have.
Saying that the difference is how it does or doesn't interfere with ones life is not all that clear. I have been bipolar all my life and learned how not to let it interfere. I was skilled in making all my physical ticks as a child not be seen as an adult like my need to lick, touch my nose then chin or problem with walking on cracks.
When I was depressed I had a bright logical reason for why I wasn't able to go out with friends for the weeks or months that it occurred so they were never worried. This is why it wasn't diagnosed in me earlier.
To make it easier there are some questions you can ask to differentiate between bipolar and depression.
How intense is your mood? How long is it lasting and can you see beyond this mood.
How long dose your mood last? Weeks, months.
How much does it interfere with your life? Does it keep you spending time with your friends or makes it difficult to get out of bed.
If you relate to these answers than it's important that you talk honestly to a Dr as well as a friend or family member.
It was the most difficult to diagnose me when I was manic because I felt so good and didn't see the harm it was causing. Most people don't seek help during this time. Now I see how harmful it was for me. I put myself in such harmful positions because I felt so powerful. I had such an intensity of emotions that made me think I was thinking so smart, would make me not think of consequences financially and sexually, I was on top of the world I thought but not seeing how I was harming others and myself from my bliss.
What I can say is that if your may be thinking you have symptoms then seek professional help. If you are depressed than there are solutions for you other than you being bipolar and you may still need help. If you are asking the question than that means something. Seek out the answers for your questions. Like the person who asked me, that person knows there is a happier more fulfilled life out there for him/her and it's worth looking for those answers. Whether your not happy because of moral dilemmas, chemical problems in your body or situations in your life that need changes, there are people to help you find answers.