Dreams can be used as containers that free patients from increased tension. This may be the principal function of certain types of dreams, called "evacuative dreams." They are dreams used for getting rid of unbearable affects and unconscious fantasies, or as a safety valve for partial discharge of instinctual drives. These dreams are observed primarily in borderline and psychotic patients, but can also be seen in the regressive states of neurotic patients during weekends and other periods of separation. Such dreams have to be differentiated from "elaborative dreams," which have a working-through function and stand in an inverse relationship to acting out: the greater the production of elaborative dreams, the less the tendency to act out, and vice versa.