ADHD is a common mental health condition. Over time, more and more people are getting diagnosed with ADHD. That’s mostly because more people are aware of ADHD than they used to be. But it does raise the question: What actually causes ADHD?
Like other mental health conditions, there’s no single explanation for ADHD. Instead, there are a variety of risk factors. The more risk factors you have, the more likely you are to develop ADHD.
Some of these risk factors include: [1, 2]
- Brain chemistry and structure: People with ADHD often show differences in parts of the brain that deal with attention, behavior, and impulse control. However, it’s not possible to reliably distinguish an “ADHD brain” from an average brain. The brain chemicals most relevant to ADHD are dopamine and norepinephrine.  Stimulant medications like Ritalin and Adderall affect these chemicals, which is why they often work so well.
- Sleep deprivation: Not getting enough sleep, or getting low-quality sleep, can cause ADHD or make symptoms worse. People with ADHD often stay up much later than the average person, making it hard to get enough sleep every night. If you have a sleep disorder, like insomnia or sleep apnea, treating it may also help with your ADHD symptoms.
- Genetics: ADHD often runs in the family. While there’s no single “ADHD gene”, there are several genes that make ADHD more likely.
- Childhood trauma: Poverty, abuse, and neglect can all increase the risk of a child developing ADHD.
- Environment: Children who are exposed to heavy metals like lead and mercury are more likely to develop ADHD early on. Premature birth and other difficulties during pregnancy can also have an effect.
- Other mental health conditions: People with ADHD often also deal with things like depression, anxiety or bipolar disorder.  Often, treating one mental health condition can help relieve the symptoms of another. Many people with autism also experience symptoms of ADHD. 
- Highly stimulating technology: Some people blame things like smartphones and video games for ADHD. The evidence for this is mixed, but people with ADHD do often spend more time with smartphones, video games, and the Internet. [6, 7, 8] And setting limits on screen time is a good idea for everyone.
These risk factors don’t just affect who will develop ADHD in the first place. They also affect how severe their symptoms will be. There are different types of ADHD, and each one may have slightly different risk factors.
Not all these risk factors are something you can control—but some of them are, like sleep habits and screen time. Medications, therapy, and lifestyle changes can help you manage your ADHD and live a full and happy life. At the end of the day, knowing why you have ADHD is less important than figuring out what works for you.
If you think you may have ADHD, take our free and confidential ADHD Test.
- Jaramillo et al. (2021). ADHD: Reviewing the Causes and Evaluating Solutions. Journal of Personalized Medicine 11(3), p. 166. Retrieved from https://doi.org/10.3390/jpm11030166
- Faraone et al. (2021). The World Federation of ADHD International Consensus Statement: 208 Evidence-based conclusions about the disorder. Neuroscience & Biobehavioral Reviews 128, pp. 789-818. Retrieved from https://doi.org/10.1016/j.neubiorev.2021.01.022
- Mehta et al. (2019). Neurobiology of ADHD: A Review. Current Developmental Disorders Reports 6, 235-240. Retrieved from https://link.springer.com/article/10.1007/s40474-019-00182-w
- Katzman. et al. (2017). Adult ADHD and comorbid disorders: clinical implications of a dimensional approach. BMC Psychiatry 17, p. 302. Retrieved from https://doi.org/10.1186/s12888-017-1463-3
- Hours et al. (2022). ASD and ADHD Comorbidity: What Are We Talking About? Frontiers in Psychiatry 13. Retrieved from https://doi.org/10.3389/fpsyt.2022.837424
- Lissak. (2018). Adverse physiological and psychological effects of screen time on children and adolescents: Literature review and case study. Environmental Research 164, pp. 149-157. Retrieved from https://doi.org/10.1016/j.envres.2018.01.015
- Tiraboschi et al. (2022). Associations Between Video Game Engagement and ADHD Symptoms in Early Adolescence. Journal of attention disorders, 26(10), 1369–1378. Retrieved from https://doi.org/10.1177/10870547211073473
- El Archi et al. (2022) Co-occurrence of Adult ADHD Symptoms and Problematic Internet Use and Its Links With Impulsivity, Emotion Regulation, Anxiety, and Depression. Frontiers in Psychiatry 13:792206. Retrieved from https://doi.org/10.3389%2Ffpsyt.2022.792206