I would argue any "friends" you have that you wouldn't be there for when its not convenient or "fun" for you to be around are not real genuine friends. I cannot imagine a single one of the people I actually consider my friends being unwilling to be there for me if I was going through a depressive spiral and I can't imagine me not being there for them if they were. Friendships are a form of relationships and that means being together through thick and thin, when its easy and when its hard. If you are unwilling to be there for your "friends" when its hard only when it's "fun" then you are not friends as far as I am concerned, you are acquaintances.