Like what Rowan said, it varies. For most high functioning autistics (including aspie's), I wouldn't exactly say it is "very serious", since they will be able to lead independent lives with only a few issues. In the UK, we have 3 levels of support depending on the severity of the ASD the person has. The vast majority of HFA's/aspie's will be in level 3 (requiring some support - this is primarily used in school's to ensure the child has access to special needs resources). Myself and the more moderate autistics find ourselves in level 2 (requiring substantial support). Basically this is the ones who would have difficulties living independently for various reasons (I'm 25, still living with parents), for example, very bad with money, hygiene, sleep, social skills, sensory issues etc which have a severe enough impact to warrant a level 2 assessment. People in level 2 can be verbal or non-verbal, but generally don't have a learning difficulty. Level 1 (requiring very substantial support) is reserved for the most severely affected autistics (you wouldn't find any aspie's here). This is for the non-verbal autistics who have intellectual disabilities too, such as those with Fragile X Syndrome, Rett Syndrome etc.
In terms of percentages, it's something like 90% of those with HFA/Asperger's will be in Level 3, 10% in Level 2 and none in Level 1. So in terms of those with Level 3, I'd say 80-90% of them could live full independent ADULT lives with no support at all (unless they end up with a related mental health issue such as sever anxiety and/or depression).
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Take car. Go to mum's. Kill Phil, grab Liz, go to the Winchester, have a nice cold pint, and wait for all of this to blow over. How's that for a slice of fried gold?
AQ-49 of 50
EQ-7 of 60
RDOS:
Neurodiverse (Aspie) score is 183 of 200.
Neurotypical (Non-autistic) score is 31 of 200
INTJ-T Personality type