How would you know if a person is bipolar ?!

Depends on when you see them. You kind of have to observe a bipolar person over a fairly long period of time to really tell. The thing is that at one point they will be excited, doing things all the time, eating very little, irritable, and sleeping very little (their manic phase) and at another they will be depressed, doing very little, sleeping and possibly eating too much, etc. The timespan for the disorder varies, and can range from a day of high and a day of low to a year of each, though those are separate disorders. It's due to a chemical imbalance that their brain has, and is corrected through use of a number of drugs, including some originally used to stabilize mood and treat seizures. It's a very confusing disorder still, at this point, but it's nothing that we cannot help with through use of drugs and therapy. Hope this helps!

Dated a bipolar girl and took Abnormal Psychology in college

As a person diagnosed with bipolar 1 severe mania without psychosis (my OFFICIAL diagnosis) I can give you some info as to how you could maybe tell, although the only way to fully tell is to get a diagnosis from a professional. You have severe mood swings-happiness, sadness, anger, etc.
Symptoms of mania can be-easily agitated or irritated, super happy or an elevated mood, hyperactivness (bouncing from one activity to another without completing any of the activities), less need for sleep, lack of self control, racing thoughts, a feeling of being "high" although not on any drug, reckless behavior- such as being promiscuous, binge eating, binge drinking and or drug use. You can be manic for weeks or even months. I tend to stay in manic phases for months at a time which pretty much means I suffer more from the manic side then the depressive side although I do get depressed. Then when the mania wears off you suddenly crash into your depression state-no energy, sleeping all the time for days at a time, crying for no reason, difficulty concentrating, not wanting to eat-weight loss or over-eating and gaining weight. You also have feelings of worthlessness, suicide, and wanting to be alone. Or you can suffer from insomnia instead of sleeping all the time. Hope this info helps and if not feel free to ask a professional.

if this person's attitude or personality changes often and randomly
like they could be laughing at one time and then start crying
usually this disease comes at a young age, or even when you are born, you can have it
Bipolar is more severe than just changing personalities, that could just mean a person is random
there are medicines to try and control this, but still there are some traits that come out

good luck :)

Bi-polar disorder is pretty easy to spot if you know what to look for. Symptoms include racing thoughts, rapid mood swings, engaging in risky/impulsive behavior and things of that sort. I have personally noticed that people who are bi-polar also tend to be compulsive liars.

As for why they're like that. They can't help it. It's a mental disorder.

http://en.wikipedia.org/wiki/Bi-polar_di…

the behaves is bad and dens to be a fat Lie's too .all draggy develop bipolar and Oslo every time they Talk they rep-it thee self. their ayes are fluky and they never look at you ayes

There is no matter to understand. Consult hurry up a Expert Doctor or it may be Late.