Unipolar depression is just depression..... unipolar meaning that the person stays at only one end of the pole on the scale. Bipolar means being at both poles... depression and mania. Everyone does have ups and downs but think of the pole as having a 0 at the center which designates a normal state, 10 being the most manic a person can possibly be and -10 being the most depressed a person can be. Normal people stay within 3 to -3 at all times during their life but they do have those ups and downs. People also usually do experience a more severe depression due to certain events like the death of a child or parent but even that will only be like a -5 and is short lived (a couple of weeks). What causes it to be Bipolar or depression is the severity or the length along the pole that someone experiences...... I have Bipolar 1 including some psychosis so I really reach 9 or -9 at any time and I am rarely anywhere near the center of the pole. That doesn't really describe all there is to Bipolar either..... there can be euphoric mania's (which I usually have) or dysphoric manias which are very bad... rage, destruction, severe self mutilation... all the powerful energy of a mania but expressed negatively. Bipolar depression is just as bad as unipolar depression... even sometimes worse because when I am depressed all the time I kinda get used to it but when I have just been manic and I am plunged iinto a depression it makes it seem so much worse for having just been so happy.... A person can also be both manic and depressed at the same time... this is called a mixed state. Books and books have been written about Bipolar so this is a pretty simple explanation but I hope it helped.
Depression - too tired to get out of bed, shower, even to brush my teeth. Cry all the time, sleep 16 hours a day. Feelings of self loathing and guilt that drive me to think of suicide but I'm to tired to even think about how to go about killing myself....... this can last from a couple of weeks to a couple of years.
Mania - Way too happy! PARTY GIRL! love drink and drugs. Talk really fast and pressured because my thoughts are going faster than my mouth can keep up with. Hypersexual - like I sleep with strangers and guys I just met on the internet or I masturbate 10 times a day. I once became bisexual because there were twice as many people to sleep with. Spending sprees..... I once spent my mortgage money on african violets, yep, $1500 on African violets (then I got depressed and let them all die). Quit my job because I wanted my vacation pay for lottery tickets and I was so convinced I would win that I started shopping and writing bad checks because I'd be rich as soon as the numbers were drawn. Only sleep 2 or maybe 3 hours a night for months on end and never feel tired. In the end I was unemployed, $30,000 in debt, and had almost lost my home. This can last for months.
I also have mixed states when I am depressed and manic at the same time which are truly the worst... By body and mind are depressed but there is this undercurrent of energy running all the time..... I'm highly emotional but the emotions tend to be negative (guilt and anger) I have intrusive thoughts and urges to mutilate myself (like wanting to stick my hands in the garbage disposal or cooking them on the BBQ). This is when I am most suseptible to suicide because I am depressed, wanting to hurt myself, and I have the mental energy to plan and carry it out.