Dual diagnosis definition......................?

Can a dual diagnosis be two different personality disorders (e.g. borderline & histrionic) or?
is one of the two always a drug or alcohol dependence / addiction?

I don't mean is it possible to have two different personality disorders because I believe that is possible, but I am talking about a psychiatric DSM IV diagnosis.

: http://alcoholdrugstreatment.info/dual-diagnosis-definition-2