I've seen people suffering from bipolar disorder at work dozens if not hundreds of times. These people are, to a greater or lesser degree, disabled by what is a very real disease brought on by a chemical imbalance. It is not a matter of being irresponsible, it's a matter of being mentally unable to control the manic and depressive episodes brought on by this disorder.
While I congratulate you on your ability to overcome some of your own mental health problems, you have to understand that your experiences don't mirror those of other mentally ill individuals. For many of them drug treatments are the only way to live a normal life.
Science can't even explain why a chemical imbalance occurs in the first place.
Their is no scientific proof that the chemical imbalance isn't a result of a person's own mood change.
As the person on this thread with a chemical balance already stated. There are no tests to find the disease. No way to prove the disease even exists. There is only a laundry list of symptoms in which this doctor has to compare you to in order to prescribe the right kind of medication.
Does that sound like science to you? Guessing on the medication based on a patients and/or doctor's preceived symptoms?