Orders teach ignorance, explanations teach intelligence.

That was my philosophy.

Children are supposed to be adults at age 18, that means they stop being told what to do by 17 1/2. By age 13 my children began getting freedoms as a gift each birthday. I will no longer tell you when to go to bed, I will no longer tell you (as hard as this is...) how to dress. They looked forward to their new right as much as a gift.

I used the term "bad day" and would stay in my room with the explanation - you are doing nothing wrong. I am not able to moderate myself today, and to protect you from unreasonable responses, I am staying in my room. I am not trying to avoid you - I love you and like when we talk. But today, I cannot. Please only come to speak with me if it is something important. I trust you to make the right decisions.

My children went through a lot- they are both balanced and responsible adults who love me in spite of all my mistakes. Not sharing reality with them wasn't something I ever did.

Edit addition: At age 14 there should be nothing you cannot share with him. Ate age 14 he understands sometimes social secrets are necessary, if he doesn't he needs to learn. Part of your explanation should be that stigma society puts on mental illness. What mental illness is. How it works on the brain. This is a great bonding opportunity. We cannot forget that we are raising people who might have issues themselves, or children with issues and we need to be honing them into acceptance without judgement and discretion without repression and pretense.