Because an attic is located at the top of a house, an attic in a dream is associated with the head (the top of the body), and therefore with the intellect or spirituality.
A cluttered attic in a dream can mean that you have too much on your mind; you need to take some time to get your thoughts and plans in order.
Attics are used for storage, so if you dream about an attic, you could be recalling old memories.
A dream of a ghost or monster in an attack can represent a traumatic memory.
Old clothes that are stored in an attic may represent roles that you have played in life.