Co-Occurring Disorders (or Dual Diagnosis)
In the United States, approximately 7.9 million adults have a substance use condition and mental health problem occurring at the same time. Substance abuse and mental health disorders such as depression and anxiety are closely linked, but one does not directly cause the other. If a person is abusing alcohol or drugs, the effects could be masking symptoms of a mental health problem, which, if untreated, can worsen the substance abuse problem. Alcohol or drugs are often used to self-medicate the symptoms of depression or anxiety but in the long run end up worsening the very symptoms they initially numbed or relieved.
Courtesy of SAMHSA and www.helpguide.org