ADHD patients with a psychiatric comorbidity more likely to stop taking their ADHD medicine A research study from the The Lundbeck Foundation Initiative for Integrative Psychiatric Research iPSYCH shows that people with ADHD, who also have another psychiatric diagnosis, are more likely to stop taking their ADHD medicine. ADHD is one of the most common psychiatric disorders in childhood and is commonly treated with medication. ADHD medicine can be divided into two groups: medicine that has a stimulating effect - also known as stimulants - and non-stimulants, which are often used if a person does not respond well to the other form of medicine.