Common comorbidities associated with ADHD along with typical ages of onset

Harold Robert Meyer | The ADD Resource Center  Reviewed 08/16/2025 Published 09/28/2025
Listen to understand, rather than to reply.

1. Oppositional Defiant Disorder (ODD)
   • Age of onset: Usually before 8 years old
2. Conduct Disorder (CD)
   • Age of onset: Childhood or adolescence (varies, often school age)
3. Anxiety Disorders (including Generalized Anxiety Disorder)
   • Age of onset: Often in late childhood to adolescence
4. Depression (including Major Depressive Disorder and Dysthymia)
   • Age of onset: Adolescence or sometimes earlier; depressive symptoms can emerge secondary to ADHD stress
5. Bipolar Disorder
   • Age of onset: Often adolescence; comorbid ADHD may lead to earlier onset below 18 years
6. Tic Disorders (including Tourette’s syndrome)
   • Age of onset: Early childhood, typically before 10 years old
7. Learning Disabilities (language, reading, writing)
   • Age of onset: Early school years, when academic demands reveal difficulties
8. Executive Function Difficulties
   • Age of onset: Early childhood, usually apparent as ADHD symptoms appear
9. Substance Use Disorders (in adults with ADHD)
   • Age of onset: Typically adolescence or adulthood
10. Obsessive-Compulsive Disorder (OCD)
    • Age of onset: Usually late childhood to adolescence

These conditions often co-occur with ADHD and may require their own specific treatments alongside ADHD management. Early identification and intervention can be crucial as they significantly affect prognosis and quality of life. Some conditions like ODD and learning disabilities often emerge early in childhood, while mood disorders like depression and bipolar disorder often start in adolescence or later. Tic disorders tend to start in early childhood as well. Bipolar disorder onset can be earlier in individuals with comorbid ADHD than in those without ADHD.

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The dangers of self-diagnosing a psychological or mental condition include:

• Misidentification of Symptoms: People may wrongly label their symptoms, leading to inappropriate or harmful treatment.
• Delaying Proper Treatment: Incorrect self-diagnosis can delay seeking professional care, worsening the actual condition.
• Worsening Health: Taking wrong or inadequate treatment based on self-diagnosis can exacerbate problems.
• Missing Serious Conditions: Self-diagnosis can overlook underlying serious issues requiring immediate attention.
• Psychological Impact: Misdiagnosis may cause unnecessary stress, anxiety, panic, or hopelessness.
• Cyberchondria: Excessive online symptom research can heighten anxiety.
• Confirmation Bias: Individuals might unconsciously adopt behaviors to fit their self-diagnosed condition, even if inaccurate.
• Resistance to Professional Help: A self-diagnosed person may reject professional opinions that contradict their view, delaying care.
• Trivializing Normal Experiences: Self-diagnosis can misattribute normal human feelings, cultural differences, or temporary issues to chronic disorders.
• Harmful Coping: Self-diagnosis may lead to dangerous behaviors like self-medication.
• Lack of Professional Assessment: Effective diagnosis requires tests and evaluations by trained professionals, which self-diagnosis lacks.
• Social Media Influence: Social media often oversimplifies complex conditions, causing misinformation and misdiagnosis.

While self-understanding mental health is important, relying solely on self-diagnosis poses serious risks. A professional evaluation ensures accurate diagnosis and effective treatment suited to your individual needs, avoiding misdiagnosis and harmful outcomes.

If you are even reading this, it’s time to see your healthcare professional!

In the USA and Canada, you can call or text 9-8-8 for free, 24/7 mental health and suicide prevention support. Trained crisis responders provide bilingual, trauma-informed, and culturally appropriate care. The ADD Resource Center is independent from this service and is not liable for any actions taken by you or the 988 service. Many other countries offer similar support services.

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Disclaimer: Our content is for educational and informational purposes only and is not a substitute for professional advice. While we strive for accuracy, errors or omissions may occur. Content may be generated with artificial intelligence tools, which can produce inaccuracies. Readers are encouraged to verify information independently.

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