ADHD and Other Conditions
There are many similarities between ADHD and other conditions. For example, both ADHD and anxiety can cause restlessness and trouble concentrating. Both can also make it hard to sit still or control impulsive behavior.
ADHD and depression share some symptoms, too. For instance, people with either condition may have trouble sleeping and may lose interest in activities they once enjoyed. They may also have low self-esteem.
There are also similarities between ADHD and learning disorders. Both can cause problems with paying attention, staying organized, and meeting deadlines.
ADDitude Magazine says: "Roughly 80 percent of those with ADHD are diagnosed with at least one other psychiatric disorder sometime during their life. The most common ADHD comorbidities are learning disabilities, anxiety, depression, sensory processing disorder, and oppositional defiant disorder. Learn the symptoms of conditions related to ADHD here."
With this in mind, be aware that in assessing someone's symptoms, not only could the symptoms relate to another disorder but they could relate to both disorders.
The best way to determine if someone has ADHD is to see a doctor or mental health professional for an evaluation. This is not a simple question and it should be addressed by a qualified professional.