Depression that gets worse when the drinking stops, or anxiety that never fully lifts no matter how long your loved one stays sober. That pattern is common, and it has a name. Dual diagnosis means a mental health condition and a substance use disorder are happening at the same time, in the same person. This is the norm in addiction treatment, not the exception. When you treat only the addiction and ignore the mental health side, relapse is far more likely. Both conditions need attention together.