Consciousness and Cognition 22 (2013) 708–715

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Consciousness and Cognition

journal homepage: www.elsevier .com/locate /concog

Short Communication

Are delusional contents replayed during dreams?

1053-8100/$ - see front matter � 2013 Elsevier Inc. All rights reserved.http://dx.doi.org/10.1016/j.concog.2013.04.006

⇑ Corresponding author. Address: Dipartimento di Salute Mentale, A.O. San Paolo, via Antonio di Rudinì 8, 20142 Milan, Italy. Fax: +39 02 818E-mail address: armando.dagostino@unimi.it (A. D’Agostino).

Armando D’Agostino a,b,⇑, Giacomo Aletti c, Martina Carboni a,b, Simone Cavallotti a,b,Ivan Limosani a, Marialaura Manzone a, Silvio Scarone a,b

a Department of Mental Health, San Paolo Hospital, Milan, Italyb Department of Health Sciences, Università degli Studi di Milano, Italyc Department of Mathematics ‘‘Federigo Enriques’’, Università degli Studi di Milano, Italy

a r t i c l e i n f o a b s t r a c t

Article history:Received 20 June 2012

Keywords:SleepDreamingMemory consolidationPsychosisDelusionsContinuity

The relationship between dream content and waking life experiences remains difficult todecipher. However, some neurobiological findings suggest that dreaming can, at least inpart, be considered epiphenomenal to ongoing memory consolidation processes in sleep.Both abnormalities in sleep architecture and impairment in memory consolidation mech-anisms are thought to be involved in the development of psychosis. The objective of thisstudy was to assess the continuity between delusional contents and dreams in acutelypsychotic patients. Ten patients with a single fixed and recurring delusional content wereasked to report their dreams during an acute psychotic break. Sixteen judges with fourdifferent levels of acquaintance to the specific content of the patients’ delusions wereasked to group the dreams, expecting that fragments of the delusional thought wouldguide the task. A mathematical index (f, t) was developed in order to compare correctgroupings between the four groups of judges. Most judges grouped the dreams slightlyabove chance level and no relevant differences could be found between the four groups[F(3,12) = 1.297; p = n.s.]. Scoring of dreams for specific delusional themes suggested acontinuity in terms of dream and waking mentation for two contents (Grandiosity andReligion). These findings seem to suggest that at least some delusional contents recurwithin patients’ dreams. Future studies will need to determine whether such continuityreflects ongoing consolidation processes that are relevant to current theories of delusionformation and stabilization.

� 2013 Elsevier Inc. All rights reserved.

1. Introduction

1.1. Sleep-dependent memory consolidation in the healthy brain/mind

Dream content is thought to reflect several aspects of the dreamer’s waking life and many laboratory studies have con-firmed what is generally termed the continuity hypothesis of dreaming (Schredl & Hofmann, 2003). However, someauthors suggest that universal aspects of dreams are wrongly attributed to individual experiences when they shouldbe interpreted as generic responses to common brain activation patterns shared across the sleep of all human subjects(Hobson & Kahn, 2007). Consolidation of new memory traces into long-term storage has been proposed as a plausible

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function of sleep, whereby key elements of recent experiences are integrated with previously encoded remote and seman-tic memories (Wamsley & Stickgold, 2011). Some evidence seems to support the contribution of Slow Wave Sleep in con-solidating hippocampus-dependent episodic memories, whereas REM sleep appears to be more important for proceduraland emotional memory consolidation (for a review, see Diekelmann & Born, 2010). The progression from quiet waking tosleep onset, NREM and REM sleep, has been experimentally correlated to an increase in vivid, hallucinatory percepts thatare bound together hyperassociatively in bizarre dream experiences (for a review, see Stickgold, Hobson, Fosse, & Fosse,2001). Given this strong brain/mind correlation, the dream process itself could somehow reflect the activation and recom-bination of mnemonic elements during sleep (Schwartz, 2003). However, the mechanism through which this process con-tributes to the generation of a complex, multimodal sensory experience remains unclear. Indeed, hippocampal activity hasbeen shown to increase during REM sleep in comparison to both wakefulness and NREM sleep but complete episodicmemories are rarely found in dreams (Hobson, Pace-Schott, Stickgold, & Kahn, 1998). It has been proposed that dreamsincorporate memory fragments relative to waking life experiences that have occurred 5–7 days before the dream at agreater rate than those from 2 to 4 days before the dream (Nielsen, Kuiken, Alain, Stenstrom, & Powell, 2004). This‘‘dream-lag effect’’ was suggested by experimental findings developed on the basis of the well-known concept of day res-idue, defined by Sigmund Freud as the incorporation of waking life elements within the dream. The confirmation of thisfinding in several studies, some of which rigorously designed to overcome methodological shortcomings (for example,Blagrove, Henley-Einion, Barnett, Edwards, & Heidi Seage, 2011), supports the view that dreaming and wakefulness arecontinuous subjective experiences. Indeed, learning-related hippocampal excitability has been shown to last approxi-mately 1 week in several animal studies, when excitation of neocortical neuronal complexes is observed (Nielsen & Sten-strom, 2005).

Two major obstacles have thus far delayed the possibility of correlating neurofunctional modifications to ongoing mem-ory processing in dreams. First of all, direct access to the dream experience is not possible with the exception of lucidity, arare phenomenon that has been hypothesized to be a hybrid state of consciousness (Dresler et al., 2011; Voss, Holzmann,Tuin, & Hobson, 2009). Dream reports, that are commonly used to infer knowledge on brain function, are memory reportsthat invariably involve two types of cognition, given that they are produced during sleep and reported during wakefulness(Schwartz & Maquet, 2002). Second, the possibility of accurately relating episodic or semantic memory fragments found indreams to waking life experiences is limited by the broad variability of thoughts, emotions, interactions, events, etc. whichcharacterize the dreamer’s wakefulness.

1.2. Relationship between dream mentation and psychosis

Abnormal sleep architecture and impaired memory consolidation processes have been linked to the development ofpsychosis (Keshavan, Montrose, Miewald, & Jindal, 2011). The subjective experience of dreaming has been shown toshare neurobiological and phenomenological similarities with psychosis (Limosani, D’Agostino, Manzone, & Scarone,2011), but the relationship between sleep-dependent memory consolidation, cognitive deficits and psychotic symptomsfound across diagnostic categories remains unclear. One possible approach is to explore the distinctive features of dreammentation during psychotic breaks. To the best of our knowledge, very few studies previously assessed the manifest con-tent of dreams in Schizophrenia. Apprehension, death and mutilation-related anxieties as well as increased rates ofambivalent hostility were found to characterize the emotional tone of patients’ dreams (Carrington, 1972; Kramer &Roth, 1973; Schnetzler & Carbonnel, 1976; Stompe et al., 2003). The increased rates of threats towards the dream Selffound in comparison to control populations were intuitively correlated to delusional persecutory experiences in wakinglife (Carrington, 1972; Langs, 1966; Noble, 1951; Stompe et al., 2003). According to this line of research, generic delu-sional themes, i.e. Grandiosity or Persecution appear to recur within patients’ dreams rather than specific contents. How-ever, one Canadian group recently found that differences between the dreams of schizophrenic subjects and those ofnormal controls disappear after controlling for report length (Lusignan et al., 2009) and that ‘‘sleep stage cognitive stylein schizophrenia is comparable to that observed in healthy individuals, with NREM sleep dream reports being morethought-like, less elaborate and less bizarre than REM sleep dream reports’’ (Lusignan et al., 2010). In most studies,dreams were collected from chronic schizophrenic subjects with varying degrees of active psychosis, so little or no infer-ence can be made on the continuity between sleep mentation and waking thought processes during acute psychoticbreaks.

1.3. Objectives

Two distinct experimental procedures were designed to assess the continuity of dream content with delusional thoughtsin acutely psychotic inpatients. (1) Several judges were asked to independently group the dreams of 10 subjects selected onthe basis of their remarkably fixed and recurrent delusion. We hypothesized that judges with both a professional knowledgeof delusional thought formation and direct acquaintance with patients’ specific delusional systems would recognize frag-ments more accurately within their dreams during an acute psychotic break. (2) The same dream reports were scored forthe presence of typical delusional themes. Our objective was to confirm that correct identification of dreamers dependedon the presence of delusional themes in their dreams.

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2. Methods and results

2.1. Patient sample

Table 1 shows the demographic and clinical characteristics of the 10 participants. All actively psychotic patients admittedto the psychiatric ward of the San Paolo Hospital in Milan, Italy, over a period of 12 months, were screened for inclusion inthis study. Inclusion criteria were (i) at least 4 hospitalizations in the previous 2 years with an entry diagnosis of acute psy-chosis, (ii) the recurrence of a fixed delusion within these episodes, (iii) marked to severe global rating of delusions uponadmission and at the end of the dream collection period. Content of delusions was documented by examining all availableclinical charts from the previous 2 years. Exclusion criteria were relevant cognitive impairment, alcohol and psychoactivesubstance abuse and a present or past history of a serious medical or neurological condition, including perinatal injury, cra-nial trauma, mental retardation and parasomnias. The subjects gave informed consent to use their reports in research butwere not aware of the specific aim of this study.

2.2. Clinical assessment

Clinical assessment was performed by using the Brief Psychiatric Rating Scale (BPRS, Overall & Gorham, 1962) and theScale for the Assessment of Positive Symptoms (SAPS, Andreasen & Olsen, 1982). Only participants with SAPS Item 20Score P 4 throughout the dream collection period were included in the study (see next paragraph). Available reference val-ues for the overall psychopathological assessment indicate that participants were on average markedly ill when the dreamcollection period ended (Leucht et al., 2005). Mini-Mental State Examination (MMSE, Folstein, Folstein, & McHugh, 1975)was administered at baseline and participants were included if they scored above the age- and education-adjusted cut offfor cognitive impairment.

None of the patients included in the study were drug-naïve but all had discontinued treatment prior to relapse. Variouscombinations of mood stabilizers and antipsychotic agents were administered to all patients during the week in which theexperimental material was collected.

2.3. Collection of dream reports

During the first week of hospitalization participants were asked to keep a dream diary where each morning they couldreport dreams recollected upon awakening. As instruction, participants were asked to report as many dreams as they couldrecollect and to accurately report the whole development of the dream plot whenever possible. Diaries were discontinuedwhen clinical assessment began to suggest a significant remission of symptoms as evaluated by a SAPS Item 20 Score 6 3.

Table 1Demographic and clinical description of the population.

Patient Sex Age (y) Education (y) DSM-IV-TR Diagnosis BPRS total score SAPSa

Items 8–19 [Score] Item 20

S.M. M 45 12 Schizophrenia – Paranoid Type 53 Persecution [5] 4Mind Reading [4]

F.L. F 60 13 Bipolar Disorder I – Manic Episode, Severe WithPsychotic Features

49 Persecution [4] 4

F.B. F 37 13 Schizophrenia – Paranoid Type 49 Religious [4] 4

B.S. F 53 2 Schizophrenia – Paranoid Type 44 Religious [5] 5Control [4]

C.M. F 54 8 Bipolar Disorder I – Manic Episode, Severe WithPsychotic Features

49 Grandiosity [5] 5

R.S. M 42 8 Schizophrenia – Disorganized Type 70 Persecution [5] 5Thought Insertion [5]Thought Withdrawal [5]

S.E. M 28 13 Bipolar Disorder I – Manic Episode, Severe WithPsychotic Features

48 Grandiosity [4] 4

A.I. F 70 13 Schizophrenia – Paranoid Type 53 Persecution [5] 5Grandiosity [4]

R.A. M 48 13 Bipolar Disorder I – Manic Episode, Severe WithPsychotic Features

64 Persecution [5] 4

L.C. F 47 8 Schizophrenia – Paranoid Type 41 Religious [5] 5Reference [5]

a SAPS Items 8–19 score specific contents of delusions and Item 20 indicates a Global rating of delusions. Score range for each item is 0 (none)–5 (severe).

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Collected dreams were transcribed on a word processing software and then edited by removing all specific identifiers such asthe proper names of people and places. Clear references to the dreamer’s gender were also neutralized given the potentialinfluence on dream classification (Domhoff & Schneider, 2008; Schredl, Becker, & Feldman, 2010). Enrolment of participantswas completed when 10 subjects had reported at least 4 dreams longer than 40 words each. Forty reports belonging to 10subjects (4 dreams per patient) were then randomly assigned cardinal numbers (1–40).

2.4. Judge selection and procedure

2.4.1. Study stage I16 judges were chosen and divided into four groups (A–D) on the basis of their cultural and professional background and

their acquaintance with the patients. All judges had an education mounting to 19 years. Group A included 4 female board-certified psychiatrists who were working on the ward at the time of data collection (mean age = 35 years); Group B included2 male and 2 female professional nurses who worked on the ward at close daily contact with the patients (mean age = 37.8);Group C included 2 male and 2 female board-certified psychiatrists who did not work on the same ward and consequentlyhad no contact with the patients (mean age = 48.8); Group D included 2 male and 2 female judges with a University-levelinstruction in different fields who had no direct experience with psychiatric disorders and had never met the patients (meanage = 49.5).

All judges were carefully instructed on the objectives of this study and were informed that the 40 dreams belonged to 10patients with the previously specified characteristics. In particular, psychiatrists in Groups A were the physicians who trea-ted the patients at the time of data collection. Obviously, not all were directly in charge of all participating patients. Nonthe-less, all judges belonging to this group were aware of the patients’ specific delusions given close contact on the ward anddaily participation in routine clinical meetings. These judges were clearly told that the dreams belonged to a restricted poolof psychotic patients they knew well and were aware of the previously specified inclusion and exclusion criteria. Likewise,nurses in Group B were rotating on the ward 24 h a day at the time of data collection and were given the same informationon the patients.

All judges were given the reports and asked to group them by author knowing that each patient had contributed 4dreams. Judges were also informed on their level of acquaintance with the participating subjects to test the hypothesis thatthose in Groups A and B would complete the assignment more easily by recognizing their patients’ delusional themes. Thisprocedure is largely based on a previously published scheme (Hobson & Kahn, 2007).

2.4.2. Study stage IIOne judge was chosen from our research group (M.C.) on the basis of her expertise in both dream scoring procedures and

the use of psychopathological rating scales. Blind to both the origin of the transcripts and the design of the study, she wasinstructed to score dream narratives according to SAPS Items 8–19. Each item of this scale reflects a specific delusional themewhich can be scored 0–5 according to the fixity of the patient’s delusion. In order to adapt this psychometric tool to dreamcontent, the judge was instructed to evaluate the presence of each specific theme (i.e. persecution, grandiosity, guilt) in thedream on a 0–5 scale.

2.5. Statistical analysis

2.5.1. Study stage IWhen all the judges had grouped the dreams by assigning each of the 40 reports to each of 10 authors, the data were

analyzed with the aid of a mathematician. An index (f, t) was developed to compare the groups of judges, where (f) indicatesthe number of correct groupings of 4 dreams per subject and (t) indicates the number of correct groupings of 3 dreams persubject. Table 2 shows the distribution of (f, t) indexes for each judge, extracted by the full table of possible results that can befound in Appendix A (Supplementary material). The following procedure was followed to assign each judge an (f, t) index:

– The probability p(f, t) was calculated for each (f, t) pair.– pairs were ranked on the basis of a decreasing p(f, t) from (10,0) to (0,0) where, for example, (5,4) ranks higher than

(6,2).– pct(f, t) was calculated on the ordered list and a preliminary index (f, t) was calculated as the logarithm of the percen-

tile function: �log10(pct(f, t)).– The final index (f, t) is the 0–1 normalized score obtained with the following formula:

Indexðf ; tÞ ¼ �log10ðpctðf ; tÞÞ�log10ðpctð10;0ÞÞ

According to the results table shown in Appendix A, p(0, 0) � 96%. Consequently, the result of at least one correct group-ing of 3 dreams per subject [index = (0, 1)] is statistically significant at the p = .05 level. Results obtained by judge Groups A toD were compared by One-way Analysis of Variance (ANOVA).

Table 2Indexes developed for judges belonging to groups A, B, C and D.

Judge Index

A1 0.111A2 0.452A3 0.111A4 0.153

B1 0.207B2 0.05B3 0.153B4 0.207

C1 0C2 0.153C3 0.05C4 0.111

D1 0.111D2 0.207D3 0.177D4 0.383

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2.5.2. Study stage IIOnce a score was assigned to each of the 40 dreams for all coded delusional themes, a mean score was calculated for each

subject on each of the evaluated SAPS items (see Appendix B – Supplementary material). Linear regression analyses wereperformed to assess the relationship between specific themes found in dreams and their homologues scored in wakefulness.All data analyses were performed with the Statistical Package for the Social Sciences version 19.0 (IBM SPSS Statistics Version19, 2010).

2.6. Results

2.6.1. Study stage IFig. 1 shows the mean Group indexes. Overall, judges’ grouping of dream reports was slightly above chance level. Their

scores varied from 0 to 0.45, with the mean and the median scores at 0.17 and 0.15 respectively. While 3 of the 12 judgesgrouped the reports at chance level or below, the other nine judges all scored slightly above chance level. The two most suc-cessful judges correctly grouped the four reports of two patients and three reports of another four and three patients respec-tively [Judge A2 Index (2,4) = 0.452; Judge D4 Index (2,3) = 0.383]. Interestingly, the highest average group score wasobtained by those who were neither formed in clinical psychiatry nor had ever met the patients (Group D, see Fig. 1). How-ever, this score was not found to be statistically different from that of the other three groups (ANOVA yielded no statisticallysignificant differences between the four groups [F(3,12) = 1.297; p = n.s.]).

2.6.2. Study stage IIRegression analyses yielded a positive linear relationship between dreams and wakefulness for Grandiosity and Religious

themes. Grandiose delusion scores predicted analogous themes in dreams (b = .71, t(9) = 2.49, p < .05) and also explained a

Fig. 1. Mean judge group indexes on the task of relating dream narratives to individual subjects belonging to a population of acutely delusional inpatients.

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significant proportion of variance in grandiose dream content scores [F(1,8) = 8.119, p < .05]. Likewise, Religious delusionscores predicted the same themes in dreams (b = .71, t(9) = 2.49, p < .05) and also explained a significant proportion of var-iance in religious dream content scores [F(1,8) = 8.119, p < .05]. None of the other six analyzed delusional themes predicteddream content scores (Persecution, Mind Reading, Control, Thought Insertion, Thought Withdrawal, Reference).

3. Discussion

3.1. General observations

Several observations can be made on the basis of these results. Patients enrolled in this study had a severe disorder ofthought content, with a fixed and persistent delusion which had recurred several times over the previous years, and inone case for almost 20 years. Despite the obvious recurrence of common themes (Table 1), each patient presented with ahighly specific content. For example, persecution could be by one’s neighbours or by extraterrestrial forces and grandiositycould relate to being a famous scientist or a divine authority. Delusions are considered irrational and persistent beliefs thatcannot be modified by experience. Indeed, deluded subjects are unable to use new information to constrain and remodel theexisting belief and reactivation of the delusion tends to reconsolidate and strengthen it (Corlett, Krystal, Taylor, & Fletcher,2009). During an acute psychotic break, the aberrant belief shifts to the core of patients’ waking thoughts and tends to deter-mine most of his/her behaviour. Dreams of acutely psychotic inpatients have been shown by our group to be continuous withtheir waking cognition in terms of bizarreness, possibly implying a common formal organization of the two types of men-tation (Limosani, D’Agostino, Manzone, & Scarone, 2011; Scarone et al., 2008). One previous study suggested a continuityacross delusions and dreams in terms of affective form rather than content in schizophrenic patients: threat anxieties werefound to be significantly more present in the dreams of patients with waking delusions of persecution compared to controls(Stompe et al., 2003). However, the extent to which dreams reflect specific delusional contents during acute psychotic breakshad never previously been investigated.

3.2. Relationship with previous research

It has been observed that given the broad range of memories, thoughts, and concerns any human being has during wake-fulness, brief dream reports from one individual are unlikely to be similar enough to be distinguished from similar sets ofreports of other individuals with equally diverse and complex thought patterns (Domhoff & Schneider, 2008). In the chosenpopulation, we expected the relative narrowing of waking thought contents would easily guide judges towards a correctgrouping of the reports to confirm the inclusion of delusional fragments within the dreams. Unlike previous findings inhealthy subjects (Hobson & Kahn, 2007), most of the judges completed their assignment slightly above chance level. Theseresults were neither influenced by the judges’ knowledge of typical delusional themes in general nor by their level ofacquaintance with the delusional patients. Furthermore, the objective scoring of dreams for typical delusional contents con-firmed a continuity for some themes. Although Fig. 1 clearly shows that group means were only marginally above chance, itseems reasonable to conclude that some delusional themes can be traced in the dream mentation of subjects whose wakingexperience is strongly influenced by specific delusions. These findings are in line with previous authors who suggested thatdreams are influenced by the dreamer’s waking concerns (Cartwright, Agargun, Kirkby, & Friedman, 2006; Mancia, 2004;Nielsen & Levin, 2007). In a recent Commentary, Valdas Noreika proposed several different ways to approach the (dis)con-tinuity hypotheses in Schizophrenia (Noreika, 2011). Our findings seem to support the statistical prediction of a positive cor-relation between waking experiences and dream content. Some studies have correlated impaired sleep-dependent memoryconsolidation mechanisms to the neuropsychological abnormalities that are typically described in Schizophrenia (Diekel-mann, Wilhelm, & Born, 2009). Sleep spindles, a putative neurophysiological marker of the memory consolidation dialoguebetween the hippocampus and the neocortex (Fogel & Smith, 2011), have been found to be reduced in this population (Fer-rarelli et al., 2007). Dysfunctional memory reconsolidation processes have been hypothesized to underlie delusion formationand stabilization (Corlett et al., 2009). Future studies will need to clarify whether impaired sleep-dependent consolidation ofdeclarative memories somehow contributes to the continuous reconsolidation of delusionalbeliefs.

3.3. Limitations of the study

Several limitations must be taken into account. First of all, both schizophrenic and manic subjects were on treatment withpsychoactive drugs at the time of data collection, which might have interfered with both dream mentation and dream recall.Overall, antipsychotic molecules, taken by all patients who joined our study, tend to normalize sleep architecture (Maixneret al., 1998), whereas no significant effects have been found for the anticonvulsant valproate which two of the patients wereadministered (Nofzinger & Keshavan, 2002). Whereas previous studies have shown that most antidepressants decreasedream recall frequency and could intensify the affective component of dreams (for a review, see Tribl, Wetter, & Schredl,2012), only few studies directly assessed the influence of antipsychotics and mood stabilizers on dream content and recallfrequency. To the best of our knowledge only one study clearly showed that sulpiride, a preferential blocker of dopaminereceptors, decreases the number (not the intensity) of dream recalls containing emotional aggressive and sexual contents

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(Gaillard & Moneme, 1977). Second, all participants shared a common waking context, i.e. the same psychiatric ward withthe same staff and daily routine, that has been hypothesized to influence dream content in previous studies on schizophrenicinpatients (Schredl, 2011). Third, as we did not use EEG to monitor sleep stages in our patients, we did not correlate dreamnarratives to a particular stage of sleep. Spontaneously reported dreams are generally thought to derive from REM sleepmore frequently (Nielsen, 2000), but given the frequent disruptions of sleep patterns in recently hospitalized psychotic pa-tients, no conclusions can be drawn on the basis of our experimental design. Finally, the number of dreams collected for eachpatient was small, and an increase in the number of dream reports has been shown to improve reliability when measuringinter individual differences (Schredl, 1998).

3.4. Conclusion

Some delusional themes tend to recur across dreams and wakefulness in acutely psychotic inpatients. Whether or not theincorporation of delusional themes within dreams can be related to ongoing processes of consolidation of waking experi-ences will have to be assessed in future studies.

Acknowledgments

The authors would like to thank all the patients and the many judges who volunteered for this study.

Appendix A. Supplementary material

Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.concog.2013.04.006.

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