Lucid dreaming is a specific phenomenon of dream consciousness that has been defined as the experience of knowing one is dreaming while one is dreaming (LaBerge, 1985, 2009). This has been described throughout human history and is a field of growing scientific interest (Van Eeden, 1913; LaBerge, 1990; Harb et al., 2016; Saunders et al., 2016; Aspy, 2020; Yu and Shen, 2020; Ferreira et al., 2021).

Recent research has pointed out that 55% of adults have experienced at least one lucid dream (LD) and 23% experience LDs regularly (once per month or more; Saunders et al., 2016). Lucid dreaming occurs naturally during brain maturation; it appears spontaneously in the course of adolescence, and its frequency is reduced at the age of 16, although it is also susceptible to auto-suggestion and training (Stumbrys et al., 2012; Voss et al., 2012).

It has been suggested that deliberate control is possible in approximately one-third of LDs (Soffer-Dudek, 2020; for example, changing location and deliberately waking up; Aspy, 2020), although it seems to be dependent on specific aspects of control (e.g., whether controlling the dream body or the environment) where higher rates were found (Stumbrys and Erlacher, 2017). Stumbrys and Erlacher (2017) pointed out that full control over the dream plot is possible in about two-thirds of cases, while control of the dream environment and the ability to maintain dream awareness are possible in less than half of cases, where the main predictors of LD control were higher LD frequency and dispositional mindfulness in wakefulness, as well as younger age.

The frequency of LDs in adults may be related to knowing about the phenomenon or having heard about it, and according to Neuhäusler et al. (2018), an increase in age is negatively correlated with previous knowledge of lucid dreaming, whereas female gender and higher education show a positive correlation with knowledge about lucid dreaming via literature and friends. Another study found that lucid dreamers were socially bold, dominant, experimenting, enthusiastic, and warm (Gruber et al., 1995). Individual differences in lucid dreaming frequency are large, and authors have also related it to openness to experiences, agreeableness, and neuroticism (although the effect of lucid dreaming frequency was no longer significant when controlled for nightmare frequency; Hess et al., 2017). According to Gasca and García-Campayo (2017), the frequency of LDs has been also associated with the locus of internal control, field independence (i.e., isolating relevant elements from context, without being distracted by the context in which these elements are found), openness to experience, increased creativity, and need for cognition (i.e., motivation and preference toward the activity of thinking).

While spontaneous LDs have been reported, their deliberate induction has also become widespread (Soffer-Dudek, 2020), and several techniques have been proposed and tested (e.g., reality testing, mnemonic induction of lucid dreams technique, and incubation of external stimuli into dreams; Stumbrys et al., 2012; Mota-Rolim et al., 2019; Aspy, 2020).

Research on LDs has shown its potential benefits and applications (e.g., Schädlich and Erlacher, 2012; Stumbrys et al., 2016). Lucid dreaming has been linked to mental health and well-being, increased self-confidence, psychological resilience, and positive emotions (Soffer-Dudek, 2020). Using an online survey, Schädlich and Erlacher (2012) reported five main reasons for which people used LDs: simply having fun (approximately 80%; e.g., flying, playing games, dancing, etc.); they benefit from lucid dreams by decreasing their nightmare frequency and intensity (approximately 60%); other applications such as problem-solving (approximately 30%), development of creativity (approximately 27%), and practice of specific movements (approximately 21%).

As a therapeutic approach, lucid dream therapy (LDT), i.e., training patients in induction techniques, has shown utility in the treatment of nightmares (e.g., Lancee et al., 2010; Holzinger et al., 2015; Macêdo et al., 2019), motor skills practice (Erlacher and Schredl, 2010; Schädlich et al., 2017), and treatment of traumatic stress (Soffer-Dudek et al., 2011). For the treatment of post-traumatic stress disorder (PTSD), although preliminary evidence was found for military veterans (Harb et al., 2016), LDT has not shown any beneficial effects for PTSD symptoms (Soffer-Dudek, 2020).

Despite the potential benefits and therapeutic applications of lucid dreaming, to date, the effects reported in most studies have been weak and inconsistent, and the mechanism of chance remains unclear – where gaining control, rather than dream awareness per se, may be responsible for the improvement – with no evidence supporting LDT over other evidence-based therapies (Lancee et al., 2010). For these reasons, Soffer-Dudek (2020) concluded that more research is needed on the applications of lucid dreaming, the adverse consequences of LD induction (e.g., sleep quality and psychological reality – fantasy boundaries have scarcely been investigated), and whether training people to achieve LDs is worthwhile. In this regard, Aviram and Soffer-Dudek (2018) also suggested that lucidity should not be considered necessarily suggestive of well-being. LDs may be positive or negative, depending on lucidity characteristics. These authors developed an expansive measure of several LD characteristics (the Frequency and Intensity Lucid Dream questionnaire; FILD) and explored their relations with symptomatology. In short, they concluded that lucidity characterized by high intensity (particularly, control activity and certainty of dreaming) and positive affect is related to fewer psychopathological tendencies.

The increased popularity of and scientific interest in LDs in recent years may be due in part to advances in their theoretical background and conceptualization. There is a consensus in describing LD as a continuum with different degrees of consciousness rather than a dichotomic experience (e.g., Barrett, 1992; Stumbrys et al., 2012; Gasca and García-Campayo, 2017). In this regard, Voss et al. (2013) defined lucid dreaming as hybrid states of consciousness in which part of the brain operates in the primary mode, while another part has access to secondary consciousness (i.e., the dreamer is aware of the fact that he/she is dreaming while the dream continues). Independent laboratories have validated the existence of LDs by identifying their neurophysiological correlates and showing distinct patterns of brain activation that supports the hypothesis of hybrid states with elements of primary and secondary consciousness modes (e.g., Voss et al., 2009, 2014; Dresler et al., 2012).

According to hypothesis of Hobson and Voss (2010, 2011), based on assumptions of Edelman (2003, 2005), the delusional character of ordinary dreams is caused by a predominance of the primary mode of consciousness, a distinct space in the consciousness continuum (i.e., lower-level consciousness) that is deprived of the ability to control, and characterized by a fusion of past, present, and future, where perception and emotion predominate. In contrast, the second secondary mode (higher-order consciousness), characterized by self-reflection and metacognition, enables planning ahead, reflecting on the past and contemplating the future (Hobson, 2009). Several studies have found that cognitive processing during wakefulness and sleep are related (Gasca and García-Campayo, 2017).

To measure and assess major and minor determinants of LDs, Voss et al. (2013) developed the Lucidity and Consciousness in Dreams scale (LuCiD) based on theoretical considerations and empirical observations. The authors identified eight factors, primarily based on the work by LaBerge and DeGracia (2000) and Kahn (2007), from an exploratory analysis that was validated using confirmatory analysis. These factors were proposed to differentiate between lower (primary) and higher (secondary) level consciousness in dreams, as well as to identify lucid vs. non-lucid dreams. Thus, the authors were interested in exploring the phenomenological correlates of primary and secondary consciousness in dreams (lucid and non-lucid). An initial formulation of 50 items was made by an interdisciplinary team of philosophers, psychiatrists, and psychologists and based on reports from lucid dreamers and theoretical considerations. It was subsequently reduced to 24 items in a second version before the addition of four new items regarding positive and negative emotion, specifically. The final validated LuCiD comprises 28 items distributed across eight factors involved in LD consciousness that can best be described by them (Voss et al., 2013; Voss and Hobson, 2015): (1) lucid insight (Insight; α=0.91) into the fact that what one is currently experiencing is not real but only a dream; (2) control over thought and actions in dreams (i.e., control over dream plot; Control; α=0.90); (3) logical thought about other dream characters (Thought; α=0.82), (4) perceptual realism (Realism; α=0.79) pertaining to the similarity between emotions, thoughts and events, with wakefulness as judged after awakening from the dream; (5) memory access to elements of waking life (Memory; α=0.66); (6) experiencing the dream from a third person perspective (Dissociation; α=0.56); (7) negative emotion (Negative emotion; α=0.68); and (8) positive emotion (Positive emotion; α=0.87). The eight-factor model was supported by exploratory and confirmatory factorial analyses where the leading factor was insight, followed by thought, control, positive emotion, and dissociation. The results showed that the factors that mainly distinguish LDs from ordinary dreams are both insight and control. Moreover, when comparing the scores of each factor for lucid vs. non-lucid dreams, all factors are shown to be involved in dream consciousness, except for realism and negative emotion, which do not differentiate between lucid and non-lucid dreams. This suggests that lucid insight is separable from both bizarreness in dreams and a change in the subjectively experienced realism of the dream. According to Voss and Hobson (2015), it is interesting that the factor analysis result supported both the restricted and broader definition of the LD. In particular, the strength obtained from the insight favors the simple definition, while the wide range of other factors favors the more complex definition. However, formal comparisons using factorial analysis for an eight- and single-factor global model (i.e., the use of one global factor to explain lucidity and consciousness in dreams) were not tested by the authors.

In summary, the results from Voss et al. (2013) showed LuCiD to be a reliable measure for assessing and quantifying lucidity and consciousness in dreams as a subjective experience, suggesting that secondary consciousness adds cognitive functions and positive emotionality to primary consciousness. Therefore, the development and validation of LuCiD facilitate understanding of the phenomenology o LDs and present an opportunity to further investigate LDs in different populations, cultures, as well as their relationship to other psychological constructs. Nevertheless, as far as we are aware, data compiled from the use of LuCiD are scarce, and validation in other languages is only available from the original version.

As previously mentioned, lucid dreaming may cover a variety of applications for the dreamer himself or herself and indeed has been proposed as a promising tool for obtaining deeper insight into the mind–body relationship (e.g., Neuhäusler et al., 2018). Thus, exploring the relationship between lucid dreaming and mind–body practices such as mindfulness – the awareness that arises through paying attention, on purpose, in the present moment, non-judgmentally (Kabat-Zinn, 2013) – may help us to better understand awareness and the relationship between awake and dream states. Gasca and García-Campayo (2017) suggest that mindfulness in waking states is related to LDs, based on the evidence concluding that mindfulness practice promotes metacognitive skills. Yu and Shen (2020) found that individuals with higher metacognition traits would have more metacognition activities in dreams and lower dream bizarreness values. Therefore, according to Gasca and García-Campayo (2017), metacognition may be a key mechanism of action meditating mindfulness practice and lucidity in dreams. Several studies have found preliminary evidence supporting the relation between mindfulness (trait), meditation experience, and frequency of LDs (e.g., Hunt and Ogilvie, 1988; Stumbrys et al., 2015; Baird et al., 2019). Nevertheless, the literature is scarce as regards mindfulness, meditation, and lucid dreaming.

The primary aim of this research was to validate a Spanish version of LuCiD. A secondary aim was to explore whether meditation experience and mindfulness trait were related to LuCiD scores.

The following hypotheses were tested:

The main purpose of the present study was to validate a Spanish version of the LuCiD. Specifically, factorial structure was examined by testing an eight-factor model for reliability by both internal consistency/test-retest and construct/concurrent validity of the scale in a sample of the Spanish general population. Overall, the results showed that the Spanish version of LuCiD is a valid and reliable measure.

As expected in the first hypothesis, CFA confirmed the eight-factor model originally proposed and validated by Voss et al. (2013), by supporting the eight factors of lucidity and consciousness in dreams: Insight, Control, Thought, Realism, Memory, Dissociation, Negative emotion, and Positive emotion. The original eight-factor model tested showed goodness of fit in contrast to a single-factor model in which items only belong to one global factor. These results are in line with those found by Voss et al. (2013), who identified and recommended eight factors involved in dream consciousness. Moreover, our study also adds new data by comparing the 8-factor structure vs. single-factor model global factor, where the use of one global factor to explain lucidity and consciousness in dreams was not supported nor recommended. The original 28 items showed adequate factor loadings as expected, similar to Voss et al. (2013). Nevertheless, item 15 was deleted from the dissociation factor as it performed poorly, as indicated in Results section. In our study, the item 15 mean was 0.78, and most of the participants answered either 0 or 1. This was the lowest score in comparison with the rest of the items, which may indicate low discriminative power. These results are congruent with Voss et al. (2013) where the mean score for item 15 was low (0.40). In addition to statistical reasons, we consider some conceptual reasons to delete it: while the item 11 (“while dreaming, I saw myself from outside”) and item 21 (“watched the dream from the outside, as if on a screen”) refer to “see oneself from outside,” item 15 refers to a different person (“while dreaming I was not myself but a completely different person”). This may explain the low factor loadings of this item in the dissociation factor.

Eight factors from the LuCiD scale presented adequate internal consistency, ranging from 0.65 to 0.83, which can be regarded as acceptable (0.60–0.70) and very good (0.80 or greater; Ursachi et al., 2015). These results are comparable to the original validation, where most factors showed good reliability. While Voss et al. (2013) found reliability levels slightly lower than desired for memory (0.66) and negative emotion (0.68), and too low for dissociation (0.56), we found the lowest levels for realism (0.66), memory (0.65), and dissociation (0.69). Differences in the dissociation factor may be due to the elimination of item 15. It is important to mention that although these were the lowest reliability values, they can still be considered to have good and adequate internal consistency. Moreover, because of their high discriminative power with regard to lucidity and consciousness in dreams, they can therefore be considered valid (Moosbrugger and Kelava, 2011; Voss et al., 2013). Furthermore, we also found significant test–retest reliability for each factor after a period of 10–15days.

Construct validity was supported by significant correlations between the eight factors of LuCiD except for Realism, which was not correlated with Insight, Control, Dissociation, or Negative emotion. In addition, Positive emotion and Negative emotion were not correlated. In our study, the most noticeable correlations (r>0.50) were found between Insight and Control, Memory and Thought, Insight and Memory, and Thought and Control. These findings are congruent with those found by Voss et al. (2013), who highlighted an interesting relationship between Insight, Control and Thought as having the leading role in LDs together with Positive emotion and Dissociation. In this regard, Control and Insight are considered defining characteristics of LDs, although control seems to be subordinate to lucid insight because it is normally only experienced in the presence of lucid insight (Voss et al., 2012, 2013). For the Memory and Thought association, as Voss et al. (2013) concluded, both constructs are related and difficult to separate. Findings regarding Realism are in line with those found in the original validation, where this factor was not significant to differentiate lucid and non-lucid dreams, suggesting that the events in lucid and non-lucid dreams are equally realistic, or equally lacking in bizarre features. Voss et al. (2013, p.19) concluded that “lucidity involves the cognitive realization that you are currently dreaming or the ability to conceptualize ongoing experience as a dream, not necessarily experiencing your dreams as unreal or as a merely virtual reality.”

It is also important to note that there were several differences in the LuCiD scores observed regarding the scales related to dream lucidity (i.e., Insight and Control) compared to those obtained by Voss et al. (2013), whose scores were lower than those of the present study, suggesting higher prevalence of lucid dreaming in the present sample. However, these findings must be interpreted with caution due to differences in procedures and data collection, as mentioned in “Limitations and Future Research Directions” section.

For the second hypothesis, evidence for validity was tested. Our findings showed a similar tendency for LuCiD scores between men and women except for Negative emotion, which indicated lower scores for men. These data are in line with Voss et al. (2013), who found the same tendency, including differences in sex for other factors (Control and Thought), but no differences regarding non-lucid dreams. The authors reported such differences but refrained from interpreting them because their sample was not representative. A possible explanation may be related to those data showing gender differences in emotional response, indicating higher emotional expressivity, particularly for negative emotions expressed by women (Deng et al., 2016). A meta-analysis exploring gender differences in dream recall found robust findings of gender differences that are affected by age showing different effect sizes and greater effects for adolescents and adults (Schredl and Reinhard, 2008). With regard to the role of age, older participants reported significantly lower scores for Control, Thought, Memory, and Positive emotion. Further research is needed to interpret these findings and explore the role of age in LDs and the possible influence of other factors (e.g., personality factors) that have not been dealt with in this study.

When comparing participants with and without meditation experience and whether they practiced meditation (meditators vs. non-meditators), the results revealed significant differences for Insight and Dissociation, indicating higher scores for meditators. Moreover, length of meditation experience was significantly associated with Control and Dissociation (i.e., higher scores for more meditation experience). Our findings showed the role of meditation practice in promoting key factors of lucid dreaming such as insight, control, and dissociation. Our findings are in line with studies indicating the influence of meditation practice on lucid dreaming (e.g., Gasca and García-Campayo, 2017), supporting that lucid dreaming occurs more frequently in long-term meditators than in meditation-naïve individuals (Baird et al., 2019). An exploratory analysis suggested significant correlations between the percentage of the time dedicated to some type of meditation practice and certain LuCiD factors. As mentioned in the results, a positive correlation was found for open monitoring practice with Insight and Control, and a negative correlation with Realism. In addition, the percentage of Compassion and Loving-Kindness meditation was significantly correlated to Negative emotion. These results may indicate a differential effect of different meditation practices (given their cognitive mechanism of action) and the promotion of lucid dreams differentially affecting LuCiD factors. Nevertheless, these data should be interpreted with caution, and rigorous and well-designed studies to further investigate this issue should be addressed.

For dispositional mindfulness, the most noticeable result was that the Observing facet was associated with six LuCiD factors (all except Realism and Positive emotion), which may suggest the influence of the “individual’s capacity to pay attention to internal and external experiences such as sensations, thoughts, and emotions” (Baer et al., 2006, 2008) in lucid dreaming. These results are congruent with those reported by Baird et al. (2019) in which LD frequency in long-term meditators was associated with the observational and decentering facets of trait mindfulness. It is important to mention that the observing facet of mindfulness has shown a controversial feature in mindfulness research, which points out that observing is one of the facets most related to and influenced by meditative practice (e.g., Lilja et al., 2013; Soler et al., 2014; Campos et al., 2019). Furthermore, total scores from the mindfulness questionnaire were also positively correlated with Insight and negatively correlated with Negative emotion. This is a relevant finding, given that insight has been highlighted as one of the key factors for LDs (e.g., Voss et al., 2012, 2013). Therefore, according to Stumbrys et al. (2015), our finding supports an existing relationship between lucidity in dreams and mindfulness during wakefulness, yet it remains unclear whether the relationship is influenced by actual meditation practice or whether it reflects some natural predispositions. People practicing mindfulness or showing higher dispositional mindfulness may have greater capacity to pay attention to the present, increasing their awareness of the ongoing experience, which seems to translate into a greater consciousness in dreams promoting lucid dreaming. Moreover, dispositional mindfulness may also promote dream control as supported by Stumbrys and Erlacher (2017), who found that higher dispositional mindfulness and younger age are predictors of dream control. Taken together, these findings highlight the key role of trait mindfulness on LDs. Finally, positive and negative affects were associated with the LuCiD factors Positive emotion and Negative emotion. These findings may suggest the influence that dispositional positive and negative trait affects have on lucid dreaming, particularly related to both the Negative emotion and Positive emotion factors, which may be particularly important to consider for LD induction or therapeutic settings such as LDT. In addition, it is worthy of note that negative affect in the wakefulness state had a stronger relationship with both positive and negative emotions in dreams in comparison with positive affect. These finding may be related to the threat simulation theory of dreams (TST; Revonsuo, 2000; Valli and Revonsuo, 2009), which states that dream consciousness is essentially an ancient biological defense mechanism, evolutionarily selected for its capacity to repeatedly simulate threatening events (Valli et al., 2005).

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

All procedures performed in studies involving human participants were in accordance with the ethical standards of the Institutional and/or National Research Committee and with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. This study was approved by the Clinical Research Ethics Committee of Aragón (Comité Ético de Investigación Clínica de Aragón, CEICA) which is part of the Health Research Institute of Aragon (Instituto de Investigación Sanitaria de Aragón, IIS Aragón), Zaragoza, Spain. Informed consent was obtained online from all individual participants included in the study.

DC drafted the first version of the manuscript with important contributions from JG-C. NM performed the statistical analysis and wrote the results sections with contributions from DC. JG-C designed and planned the study, assisted the data analyses, and collaborated in the writing and editing of the draft and the final manuscript. MM-A and DC conducted the online recruitment and the data set accuracy. PH-M, MP-G, and SG contributed to the literature searches and collaborated on the writing and editing of the final manuscript. All authors contributed to the article and approved the submitted version.

This study was partially supported by the Master in Mindfulness Programme and the Chair of Contemplative Sciences, University of Zaragoza (Zaragoza, Spain), and the Instituto de Investigación Sanitaria Aragón (IIS Aragón; Zaragoza, Spain). The funding source had no influence on the design of the study, data collection and analysis, or writing of the manuscript.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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