First off it is very important to understand that there may be no obvious reason at all for depression. When I was first diagnosed - a long time ago

- my life was very good and there was no reason at all that I could see that I should have been depressed. Sometimes people divide 'types' of depression into two kinds - 'clinical' where there is no obvious reason and 'reactive' where the cause is some particular event (a bereavement, divorce, post-natal, financial problems etc.). While I now think the divide is not as clear as that, it is still true that there certainly does not have to be any 'reason' for depression in the obvious sense. There is a chemical imbalance in the brain for whatever reason and this is a medical condition.
Which leads me to say that secondly there are millions of people with some degree of depression and a great many with serious degrees. I know it is hard to accept but the fact is that it is not that 'weird'. The immediate reaction with depression and other MH conditions is to blame yourself - its one of the big differences from non-MH illnesses - but really it is not your fault

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Very best of luck with your visit to the GP - you are doing absolutely the right thing. Let us know how you get on.
Nick.