The short answer is no. ADHD is a neurological disorder that as far as we know is genetic is most cases (some cases may be environmental factors or brain damage). Furthermore, in order to get diagnosed with ADHD, you have to have symptoms starting from a young age (before 7), very very few preschoolers have clinical depression. (fortunately). HOWEVER, depression, especially more severe depression, can cause ADHD-like symptoms, such as trouble concentrating, lack of motivation, trouble sleeping, problems learning, disorganization,etc. So, if a teen or adult suddenly develops “ADHD” symptoms, it’s probably depression. (or a sleep disorder or excessive stress). Depression needs to be treated in an entirely different way than ADHD, although in a few treatment resistant depression cases, ADHD meds might help. As far as the relationship between ADHD & Depression, you are right, most people with ADHD will develop depression at some point in their lives. Obviously the symptoms are depressing,