Dual diagnosis, also called co-occurring disorders (COD) or dual pathology is a condition of suffering from a mental illness and a comorbid substance abuse problem. It is a co-occurring disorder which means substance abuse can result in experiencing a mental illness and a mental illness can result in substance abuse. Either disorder can develop first. When someone is struggling with this problem, it is often the best decision to seek help from dual diagnosis treatment centers to make sure everything is addressed properly.

A revealing sign of a dual diagnosis includes relapsing from treatment repeatedly. Seeking treatment through dual diagnosis treatment centers for just one of these conditions can trap a person in an endless cycle. Self-medicating to cover up a mental illness can create addiction and overdose, potentially leading to death.