An alteration of consciousness that is characterized by a decreased ability to focus one's thoughts on something. Concentration difficulties can be related to difficulty staying awake, impulsiveness, intrusive thoughts or concerns, overactivity, or inattention. They can be caused by medical, cognitive or psychological problems, or, may be related to sleep disorders, medications, alcohol, or drugs. [ url:https://www.healthgrades.com/right-care/symptoms-and-conditions/concentration-difficulty ]