Adults with undiagnosed ADHD have a greater tendency to develop an addictive behavior than those who don’t have the disorder. Research suggests that substance abuse is often a manifestation of the need to self-medicate untreated symptoms. Alcohol and illegal drugs such as meth and cocaine affect the brain in a manner similar to medications like methylphenidate and amphetamine, which are usually prescribed to ADHD patients. For instance, while cocaine acts as stimulant for most people, the effect is opposite in adults with untreated, undiagnosed ADHD: enhancing their mood and helping them sleep better. It’s no surprise, therefore, why they tend to resort to these substances for temporary relief instead of approaching their local Riverside treatment center.