Depression is not always genetic unless it is coming from Bipolar syndrome. Some people have environment that causes depression, or something that has been a truma in their life and they need to deal with it. Depression can come from many reasons but there usually is a basic problem in their life. There are many examples, and most do need expert help to learn how to deal with what is doing this.
On the other hand Bipolar syndrome is definitely genetic. I am Bipolar and did not realize until age 19. I am also OCD and have Irriatable Bowel Syndrome. Anxiety and IBS go hand in hand. By the way I am 52 now and have fought this demon many years but so far came out on top. And meds....they are trial and error just like most things in life. Good Luck to you and I hope this was a bit helpful.