No cognitive state has been more misunderstood over the course of human history than dreaming. Dream science is affected by medical, psychological, social, and sleep variables, and the methodologies used to study dreams are inconsistent, at best. Still, dreaming is an important component of the human experience and the more we learn about dreaming, the more we can unlock the mysteries of the mind.

Dreams truly became part of the medical vernacular in the early 20^th century after Freud and his supporters developed techniques for psychoanalysis and dream analysis, believing that dreaming was a reconstruction of emotional events in a person’s past. Freud’s dream theories emphasized the psychopathological associations of unusual dreams and his definitions eventually led to the theory of dreams as wish fulfillment. Dreams were also used in the treatment of mental illness.

Fifty years after Freud’s work, science was able to analyze sleep through polysomnography and sleep was electrophysiologically staged. The initial theory of dreams occurring during rapid eye movement (REM) sleep has changed to an understanding that dreams occur in all stages of sleep. As medicine expanded its understanding of how the human body sleeps, the understanding of dreams diminished. Today, dreaming is considered mentation or cognition that occurs during sleep. As a culture, we have evolved away from the psychoanalytic definitions of dreams from a century ago.

Sleep is a subjective experience and its evidence-based study is limited by individual dream recall and associated pathophysiology. Dream recall varies with stage of sleep, and also varies with age, gender, and vocation. Recall is higher among women and young people, and is also higher among people with creative interests, indicating that dreaming may be a part of the creative process. Dream salience and intensity, as in nightmares, increases dream recall. A small percentage of individuals report no dream recall at all. Though rare, these individuals have no memory impairment and function completely normally in society.

Dreams are most often narratives that are nothing more than the mind organizing experiences into patterns. Dreams can be adaptive and problem-solving as the brain connects, compares, and integrates experiences and information. The content of dreams does not differ among ethnic groups, personality types, psychopathologic diagnoses, or socio-demographic categories. But, personal experiences and emotions – more often traumatic experiences — do influence dreams. Nightmares associated with posttraumatic stress disorder are frequent.

Chemicals also influence dreams. The primary neurotransmitter influencing sleep is acetylcholine; many pharmaceutical agents have anticholinergic activity, leading to the reported side effects of nightmares, hallucinations, and disordered dreaming. Stimulants and sedatives are the most commonly reported medications with such dream-altering side effects. Beta-blockers, selective serotonin reuptake inhibitors, and type-1 antihistamines can also induce disordered dreaming and nightmares.

Dreams can also bring unwanted associations including arousal, sleep terrors, confusion and disorientation, incoherent vocalization, and fragmentary dream recall. Dream-related movement or paralysis can occur and often lead to intense stress for the dreamer. Sleep talking, anxiety and panic attacks, and partial epileptic seizures can cause embarrassment, insomnia, and daytime anxiety.

Dreams are the things that our mind thinks while we are sleeping. They can be analyzed from behavioral, anatomical, chemical, physiological, and pathological perspectives. While dreams do not carry the influence in diagnosing and treating mental illness as they once did, dreams are still an imperative aspect of our emotional functioning, since they organize and expose our experiences and emotions. Dreams are a part of who we are – individually and collectively – and the science of sleep and dreaming deserves attention from clinicians and patients, alike.

References

Been H (1997). Dreams: the convergence of neurobiologic and psychoanalytic perspectives. The Journal of the American Academy of Psychoanalysis, 25 (4), 639-54 PMID: 9592367

Giustino G (2009). Memory in dreams. The International journal of psycho-analysis, 90 (5), 1057-73 PMID: 19821852

Mancia M (2004). The dream between neuroscience and psychoanalysis. Archives italiennes de biologie, 142 (4), 525-31 PMID: 15493553

Pagel JF (2012). What physicians need to know about dreams and dreaming. Current opinion in pulmonary medicine, 18 (6), 574-9 PMID: 22965274

Schneider JA (2010). From Freud’s dream-work to Bion’s work of dreaming: the changing conception of dreaming in psychoanalytic theory. The International journal of psycho-analysis, 91 (3), 521-40 PMID: 20590926

Zadra A, & Robert G (2012). Dream recall frequency: Impact of prospective measures and motivational factors. Consciousness and cognition, 21 (4), 1695-702 PMID: 23092675

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