Coping with depression is a highly individual matter, but there are a few ideas that work for most people.
My background:
I was not diagnosed until I was 43 years old. Once I knew how to identify the symptoms, I realised that I had lived with major clinical depression since before the age of 10. I am a left-handed artistic-creative personality, so it was extremely likely that I would also have depression. It is part of the artistic-creative package, which is why so many writers, poets, actors and the like neck themselves.
My father was a naval petty officer, who was a raving psychotic who went into manic rages caused by the slightest thing. My childhood was a living Hell. Imagine being in boot camp from birth to age 21, but the boot camp was run a physically and psychologically abusive psychotic who wanted to micromanage every aspect of your life.
When I was three years old I was molested by the queer next door. When I was 10 years old the same queer and two of his friends raped me. Some days I still bleed, after the scar tissue tears. When I was 16 I was drugged and raped by another queer.
Follow that with being unable to relate to 99 per cent of people because of an IQ in the genius range and perhaps a touch of Asperger's syndrome (I tick most of the boxes for high-functioning Asperger's).
During my teens and 20s I could not get a date, because I was not the type of scumbag bad boy that the girls of that age wanted. The one girl with whom I was able to form a relationship broke my heart when I was 21, when she revealed that she had been with me as a diversion, so that her parents would not suspect that she was maintaining a secret relationship with a bad boy of whom they disapproved. I went into a very, very dark place for months after that. Imagine sitting in a darkened room, sobbing, rocking back and forth and begging for death while fondling a pistol. Such is the pain of a broken heart, especially at that age.
Throw depression into that mix, stir well and you get someone who is seriously fucked up.
Once I was diagnosed I began to take SSRI anti-depressants, but that was not a complete solution. I still have bad days, during which I recite Hamlet and Macbeth to a pistol.
Additional measures that have been useful for me (and are useful for most other people) are a lot of exercise and fish oil.
Exercise releases endorphins, which is the body's feel-good hormone. Consequently, there is a benefit for both physical and mental health.
If you go to the US Food and Drug Administration database www.pubmed.com and search for omega-3 therapy for depression you will find that there is strong evidence that a daily dose of at least 8,000 milligrams of fish oil will reduce the severity of depression.
Throughout my life I have also found that karate has been of great benefit to both my physical and mental health. I think that a person would have to be a student of a martial art to understand. I cannot find the words to explain the spiritual benefit that can be derived from karate.
Dealing with depression is done one day at a time. There is no cure, because that is the way that your brain is wired. You will have good days, you will have days during which you will beg for death.
Ultimately, how you deal with it is your choice.