Selective Mutism

I may have had selective mutism through school, as I was better with family at home but at school could be mute most of the time.  It never got picked up so wasn't diagnosed with anything.  Can't say if it really was selective mutism or down to social anxiety or both or something else.  Lost in your own world could be at play, but sometimes there is a want/need to speak and you just can't and that is difficult.  It can stay with you through life unless helped, as can social anxiety.

Not sure what's available for selective mutism through the NHS - for adults is a case of finding a private therapist that can help with that, and be able to afford it.

Social Anxiety is very similar from the outside, but its down to worries about saying the wrong thing, or what people might think, or when to speak.  You have to learn to manage/change the thoughts/beliefs you have, so you free yourself to speak even if you mess up or others judge.

Yes - my son has all those sorts of social anxiety concerns - which do connect to Selective Mutism. Throughout all the years he has struggled with this it’s been so hard to get help and support for him for his Selective Mutism. The NHS wouldn’t help, Camhs didn’t help, Ed Psychs didn’t help, SALT said they didn’t help with it. We had to fight to get specialist help but by then it was a very ingrained habit and in the short time he had access to specialist support they couldn’t help him. To be honest just writing this and remembering how little support there has been over the years is upsetting. He deserved so much better. It’s had a massive impact on his life. Sorry - I’m being very negative and I don’t mean to be. But it’s been pretty heartbreaking to watch my son struggle with this. He’s the most wonderful person and yet has no friends. I want him to have the life he wants to have. 
Thank you for your reply - it really does help to talk to people who understand. When he was a school (he’s enrolled in college at the moment but not attending due to his mental health being not good) no one else seemed to understand at all - we felt like complete outsiders from normal school life. No one seemed to understand - it was very isolating. 

Yes - my son has all those sorts of social anxiety concerns - which do connect to Selective Mutism. Throughout all the years he has struggled with this it’s been so hard to get help and support for him for his Selective Mutism. The NHS wouldn’t help, Camhs didn’t help, Ed Psychs didn’t help, SALT said they didn’t help with it. We had to fight to get specialist help but by then it was a very ingrained habit and in the short time he had access to specialist support they couldn’t help him. To be honest just writing this and remembering how little support there has been over the years is upsetting. He deserved so much better. It’s had a massive impact on his life. Sorry - I’m being very negative and I don’t mean to be. But it’s been pretty heartbreaking to watch my son struggle with this. He’s the most wonderful person and yet has no friends. I want him to have the life he wants to have. 
Thank you for your reply - it really does help to talk to people who understand. When he was a school (he’s enrolled in college at the moment but not attending due to his mental health being not good) no one else seemed to understand at all - we felt like complete outsiders from normal school life. No one seemed to understand - it was very isolating. 

Its really hard with the lack of resources and understanding, harsh realities.  You may want to reach out online to other parents with sons/daughters affected by selective mutism, see what they suggest or have tried.  There might be support groups out there, or meet up with other families so not so isolated.