I have not listed 'learning disability' as an autism related condition in the list below because I do not regard someone who has a learning disability as having a medical condition although there are obviously issues around degree (disability vs difficulty?) and associated vulnerabilities including susceptibility to poor mental health. This is at heart an inconsistent stance as it could be argued that some autistic people also live with the same sorts of strengths and difficulties as non-autistic people so autism should not be considered a medical condition per se either. Autism could also be seen as one of the family of learning disabilities unrelated to intellectual ability. What this shows I think is that individuals, autistic or otherwise, cannot or should not be pinned down be a set of diagnostic labels. Diagnoses to be of value should explain difficulties where they exist, and signpost to best ways to address these.
Anxiety See https://www.anxietyuk.org.uk/ and https://www.cerebra.org.uk/help-and-information/guides-for-parents/cerebra-anxiety-guide-guide-parents/ and http://network.autism.org.uk/good-practice/evidence-base/reducing-anxiety-autistic-children-and-young-people?utm_source=AutismInsight19April2018&utm_medium=email&utm_campaign=AutismInsight19April2018&utm_term=email&utm_content=Story3A&dm_i=YA3,5L7FG,L1P9W2,LPJB2,1
Oppositional Defiant Disorder See papers by many prominent British clinicians here that set out differing perspectives about possible links between extreme demand avoidance (extreme anxiety/poor mental health in autistic people without a learning disability) and oppositional defiant disorder. Both groups call for more research into the best ways to help people with these difficulties.