Around half of all people with addiction also have a co-occurring mental health condition — depression, anxiety, PTSD, bipolar disorder, ADHD, or others. This is called dual diagnosis, and understanding it changes everything about how treatment should work and what families should expect.

What Is Dual Diagnosis?

Dual diagnosis (also called co-occurring disorders) means a person has both a substance use disorder and at least one mental health condition at the same time. It is not a rare edge case — it is the norm. Research consistently shows:

• Around 50% of people with addiction have a co-occurring mental health condition
• People with mental health conditions are twice as likely to develop addiction
• The two conditions interact and reinforce each other, making both worse
• Treating only the addiction without addressing the mental health condition leads to much higher relapse rates

Which Mental Health Conditions Commonly Co-Occur With Addiction?

• Depression — the most common co-occurring condition. Substances temporarily relieve depressive symptoms; as they wear off, depression deepens, driving more use.
• Anxiety disorders — alcohol and benzodiazepines are frequently used to manage anxiety, creating physical dependency.
• PTSD — trauma and addiction are deeply connected. Many people with addiction have experienced significant trauma.
• ADHD — stimulant misuse is particularly common in undiagnosed or undertreated ADHD.
• Bipolar disorder — substance use is extremely common during manic episodes and as self-medication during depressive phases.
• Borderline personality disorder — emotional dysregulation and impulsivity increase addiction risk significantly.

Which Came First?

This question — did the mental health problem cause the addiction, or did the addiction cause the mental health problem? — is less important than it might seem. By the time someone is in treatment, both conditions are present and both need addressing. The “which came first” question matters less than “how do we treat both.”

That said, understanding the history helps. A person who used drugs to manage long-standing depression needs depression treatment alongside addiction treatment. A person whose depression developed as a consequence of addiction may find mental health improves significantly with sustained sobriety.

Why Dual Diagnosis Matters for Families

For families, understanding dual diagnosis explains several things that may have been confusing:

• Why your loved one seems genuinely miserable even when sober
• Why standard addiction treatment hasn’t worked — it may not have addressed the underlying mental health condition
• Why relapse happens even when they seem committed to recovery
• Why their behaviour sometimes seems far more extreme than the substance use alone would explain

What Dual Diagnosis Treatment Looks Like

Effective treatment for dual diagnosis addresses both conditions simultaneously — not sequentially. Key features to look for:

• Integrated treatment — one team addressing both conditions, not separate programmes
• Psychiatric assessment — proper diagnosis of mental health conditions, not just addiction
• Medication where appropriate — antidepressants, mood stabilisers, or anti-anxiety medication alongside addiction treatment
• Trauma-informed care — given the high prevalence of trauma in this population
• CBT and DBT — both evidence-based for both addiction and mental health conditions

Online-Therapy.com offers CBT-based therapy that addresses both addiction patterns and co-occurring mental health conditions. From $40/week.

What Families Can Do

• When seeking treatment, ask specifically: “Do you treat dual diagnosis?” and “Do you have psychiatric staff?”
• Share relevant mental health history with treatment providers — your observations matter
• Be patient with a longer treatment timeline — dual diagnosis typically requires more sustained treatment than addiction alone
• Get your own support — families of people with dual diagnosis face additional complexity