A lot of people with Autism or Aspergers especially, are prone to mental illnesses in later life. I believe it is because we search for coping mechanisms for the 'offness' we feel, and can easily become fixated on the rituals/routines due to the nature of ASD.
OCD, Tourettes, Eating Disorders, Depression, Anxiety, Trictotilomania (sp), Sex Addiction and Drug/Alcohol Addiction are common. As are 'mis'diagnosises of personality disorders.
I was once told by a doctor that there is no 'limit' to the amount of things a person can be diagnosed with.
This led me to believe that having the label was not related to having the solution.
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Be not angry that you cannot make others as you wish them to be, since you cannot make yourself as you wish to be.
~Thomas à Kempis
"Be plain, good son, and homely in thy drift;
Riddling confession finds but riddling shrift"
~Shakespeare