Obsessive-compulsive disorder is a type of mental illness. People with OCD can have either obsessive thoughts and urges or compulsive, repetitive behaviors.
Yes, s a mental disorder where people feel the need to check things repeatedly, perform certain routines repeatedly
I haave a friend who is OCD.  She is unable to control either the thoughts or the activities for more than a short period of time.
These activities may include checking if door is closed or washing of hands,amongst others