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  • Comorbidity is when two or more disorders or illnesses occur in the same person, at the same time or one after the other.  The illnesses may interact with each other, affecting a person’s symptoms and health outcomes.
  • Comorbidity occurs often among substance use disorders and other health disorders and physical conditions, particularly mental health disorders. Common risk factors related to person’s genes, individual characteristics, social environment and other life circumstances can contribute to both mental illness and substance use and addiction.
  • When someone has a substance use disorder and another mental health disorder, it is usually better to treat them at the same time rather than separately. Research suggests that this can increase treatment effectiveness for both disorders.

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