Relationship with medical conditions

There is evidence that certain medical conditions (normally only neurological conditions) can impact dreams. For instance, some people with synesthesia have never reported entirely black-and-white dreaming, and often have a difficult time imagining the idea of dreaming in only black and white.^[81]

Therapy for recurring nightmares (often associated with posttraumatic stress disorder) can include imagining alternative scenarios that could begin at each step of the dream.^[82]

Other associated phenomena

Incorporation of reality

During the night, many external stimuli may bombard the senses, but the brain often interprets the stimulus and makes it a part of a dream to ensure continued sleep.^[83] Dream incorporation is a phenomenon whereby an actual sensation, such as environmental sounds, are incorporated into dreams, such as hearing a phone ringing in a dream while it is ringing in reality or dreaming of urination while wetting the bed. The mind can, however, awaken an individual if they are in danger or if trained to respond to certain sounds, such as a baby crying.

The term "dream incorporation" is also used in research examining the degree to which preceding daytime events become elements of dreams. Recent studies suggest that events in the day immediately preceding, and those about a week before, have the most influence.^[75]

Apparent precognition of real events

According to surveys, it is common for people to feel their dreams are predicting subsequent life events.^[84] Psychologists have explained these experiences in terms of memory biases, namely a selective memory for accurate predictions and distorted memory so that dreams are retrospectively fitted onto life experiences.^[84] The multi-faceted nature of dreams makes it easy to find connections between dream content and real events.^[85]

In one experiment, subjects were asked to write down their dreams in a diary. This prevented the selective memory effect, and the dreams no longer seemed accurate about the future.^[86] Another experiment gave subjects a fake diary of a student with apparently precognitive dreams. This diary described events from the person's life, as well as some predictive dreams and some non-predictive dreams. When subjects were asked to recall the dreams they had read, they remembered more of the successful predictions than unsuccessful ones.^[87]

Lucid dreaming

Lucid dreaming is the conscious perception of one's state while dreaming. In this state the dreamer may often (but not always) have some degree of control over their own actions within the dream or even the characters and the environment of the dream. Dream control has been reported to improve with practiced deliberate lucid dreaming, but the ability to control aspects of the dream is not necessary for a dream to qualify as "lucid" — a lucid dream is any dream during which the dreamer knows they are dreaming.^[88] The occurrence of lucid dreaming has been scientifically verified.^[89]

Oneironaut is a term sometimes used for those who lucidly dream.

Dreams of absent-minded transgression

Dreams of absent-minded transgression (DAMT) are dreams wherein the dreamer absentmindedly performs an action that he or she has been trying to stop (one classic example is of a quitting smoker having dreams of lighting a cigarette). Subjects who have had DAMT have reported waking with intense feelings of guilt. One study found a positive association between having these dreams and successfully stopping the behavior.^[90]