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This paper presentsÂ a literature reviewÂ to determine whether precipitating factors of depersonalization (DP) and derealization (DR) are best described by two dimensions of affective phenomena-valence and arousal. DP/DR precipitators are reviewed and classified in relation to the valence and arousal dimensions representing each of the four quadrants of the circumplex model of emotion. The findings indicate that the valence and arousal variables were significant predictors of emotions expressed in DP/DR triggers. Implications are discussed with respect to the multifaceted nature of DP/DR, clarifying normal and abnormal DP/DR, and identifying needed areas of research.
Keywords: affect, arousal, circumplex model of emotion, depersonalization, derealization
Depersonalization/derealization disorder (DP/DR-D) involves recurrent or persistent episodes of deperÂsonalization and/or derealization, states that are characterized by a distortion in self-awareness. Depersonalization (DP) often includes an altered, detached, or estranged subjective experience of one's self, one's mental processes, and one's body during which people feel that they are robots or that they are in a dream. This is often accompanied by derealization (DR) in which the external world also appears strange or unreal (DSM-IV, American Psychiatric Association, 1994; ICD-10, World Health Organization, 1992). Sufferers often report feeling as if they were observing a play in which they are participating or as if they were watching themselves from a distance. They may feel that they are not in control of their actions and fear that they are going crazy. However, their capacity forÂ realityÂ testing reÂmains intact (e.g., knowing that one is not literally a robot). In addition to these core diagnostic criteria, sufferers often report marked distress or impairment in social, occupational, or other functioning. Recent studies suggest the prevalence of chronic pathological DP/DR is within the range of 1-2% (Hunter et al., 2004; Johnson et al., 2006; Michal et al., 2009).
Epidemiological surveys have found that mild and transient symptoms of DP/DR are common in the general population, with a lifetime prevalence rate of between 30-70% (Dixon, 1963; Sedman, 1966, 1970; Trueman, 1984). The symptoms of DP/DR occur in association with a wide range of circumstances such as stress, hypnosis (Wineburg & Straker, 1973), hypnogogic and hypnopompic states, sleep deprivation (Bliss et al. 1959), fatigue, sensory deprivation (Reed & Sedman, 1964), hyperventilation (Cohen, 1988), and or drug or alcohol use (Good, 1989). The relatively high rates of reporting of these symptoms, in combination with the diverse range of precipitants, increase the need for clarification of the spectrum of DP/DR from general, normal experiences to disabling, pathognomic episodes. In other words, if transient DP/DR is such a frequentÂ occurrence, why are the symptoms perpetuated in some people but not in others?
A recent cognitive-behavioural conceptualization of DP/DR-D (Hunter, Phillips, Chalder, Sierra, & David, 2003) proposes that the chronic condition of DP/DR-D results from catastrophic misinterpretations of the common, but normally transient, symptoms of DP/DR. According to this view, most people experience temporary DP/DR but most people attribute it to situational stressors and pay little attention to it, thus leading to the decrease in symptoms as the situational factors alleviate. On the other hand, people who develop the chronic condition may catastrophically misinterpret the transient symptoms of DP/DR, for example, taking them as indicative of serious mental illness and/or brain dysfunction. This kind of thinking is suggested to lead to anxiety, which in turn fuels the continuation and worsening of symptoms.
This account,Â however, appearsÂ to oversimplify the nature of pathological DP/DR. The cognitive-behavioural model (Hunter et al., 2003) rests on the premiseÂ that pathological DP/DR is onlyÂ a variation of the same underlying symptoms as those experienced in transient episodes: "The symptoms of depersonalisation disorder are the same as those experienced in transient episodes, except that in DPD the symptoms are experienced chronically, cause significant distress and result in functional impairment" (p. 1453). Yet the problem for researchers is thatÂ while the "symptoms" of depersonalization/derealization disorder may be the same as those experienced in transient episodes (e.g., feelings of unreality), the "quality" of the DP/DR may differ (Steinberg, 1994). In this author's view, then, the relationship between pathological DP/DR and transient episodes requires further explication.
Working from the premise that pathological depersonalization has key distinguishing features-and involves processes that are qualitatively distinct from transient episodes-Steinberg (1994) suggested that depersonalization precipitants vary along the normal/abnormal continuum. According to Steinberg, brief episodes of "common-mild depersonalization," defined as an isolated event or "one or few episodes," lasting "seconds to minutes," would typically be triggered by extreme fatigue, sensory deprivation, drug or alcohol intoxication, sleep deprivation, and stress. These triggers,Â however,Â would not seem sufficient to explain pathological depersonalization/derealization, and, although stressful events may precipitate the condition, it can become chronic even without any identifiable stress (Steinberg, 1994).
To better understand the variation of DP/DR precipitants along the normal/abnormal continuum, it is importantÂ to consider two dimensions of affective phenomena: valence and arousal (Russell, 1980; Barrett & Russell, 1998; Russell & Barrett, 1999). Valence refers to the hedonic quality (pleasure or displeasure) associated with affective phenomena. Arousal (or activation) refers to felt activation associated with affective phenomena. All human emotional experience (i.e., emotions such as anger, sadness and fear, as well as non-emotional affective states like fatigue, sleepiness and relaxation) can be defined as combinations of these two independent dimensions. The valence/arousal circumplex model has a long history in affective psychology and researchers advocate use of the circumplex model particularly for a systematic arrangement of conscious emotional experience (see Fabrigar, Visser & Browne, 1997; Russell & Barett, 1999 for recent reviews).
The purpose of the present article is to review the research literature for evidence that precipitating factors of depersonalization and derealization could be fitted to the circumplex structure of emotion. Since there is an extensive catalogue of factors reported to provoke depersonalization and/or derealization, and little or no theoretical basis for bringing them under scrutiny, the taxonomy of a circumplex model will not only offer a parsimonious way of conceptualizing the multifaceted nature of DP/DR symptoms, but in so doing, will also help to clarify interrelationships along the normal/abnormal continuum.
To test the hypothesis that the emotion circumplex structure generalizes to the DP/DR spectrum, a comprehensive review ofÂ theÂ literature was conducted. BasedÂ onÂ a comprehensive review ofÂ theÂ literature, 16 DP/DR precipitators were identified that have received consistent support in reviews on the topic. Figure 1 depicts the 16 precipitators in the two-dimensional Euclidean space. As predicted, the 16 DP/DR precipitators appeared to fit the circumplex structure. The vertical axis describes the arousal dimension from low (bottom) to high (top). At the high end of the vertical arousal dimension, depersonalization or derealization precipitators such as "sports" and "overwhelming joy" can be seen. Precipitators such as "fatigue" and "hypnopomic states" can be seen at the low end. The horizontal dimension describes the valence property of the behaviors from negative (left) to positive (right). Negative precipitators are items such as "stress/crisis" and "loss of self-agency," whereas positive precipitators are items such as "overwhelming joy" and "hypnotic induction."
[See Figure 1]
Figure 1. Graphical representation of circumplex structure of depersonalization/derealization.
Note: TheÂ horizontal axis indicates the valence (left = negative valence, right = positive valence), and vertical axis indicates the arousal level (top = high arousal, bottom = low arousal).
An inspection of Figure 1 shows the covariation pattern among the 16 DP/DR precipitators. Adjacent precipitators are likely to be expressed at the same time. In contrast, distant precipitators are less likely to be expressed at the same time. For example, the precipitators "extreme threat" and "hyperventilation" are closely aligned on the negative side of the circumplex. Thus, "extreme threat" is much more likely to accompany "hyperventilation" than by ''overwhelming joy" (which is located on the polar opposite location). Having provided an overview of the circular ordering of the DP/DR spectrum, the next task will be to review evidence for the various precipitators found to be consistent with the four quadrants of the circumplex.
Overwhelming Joy. Almost without exception, discussions of dissociative experiences have converged in thinking that these experiences are restricted to witnessing or being the victim of a traumatic event (e.g., Herman, 1996; Marmar et al., 1994; Putnam, 1995; Spiegel et al., 2000; Foa & Hearst-Ikeda, 1996, see Van der Kolk, Van der Hart, & Marmar, 1996 for review). However, dissociation during positive events has been found to occur (Pica & Beere, 1995). According to Beere's (1995a; 1995b; 2009; Pica & Beere, 1995) perceptual theory of dissociation, an event does not need to be subjectively traumatic or unpleasant to invoke dissociative characteristics. Rather, it is the overwhelming or "captivating" nature of the stimulus that triggers dissociative reactions. It is posited that in such circumstances, because perception becomes "captivated by a particular aspect of the lived situation" consequently, "different components of the perceptual background become lost, resulting in the dissociative reaction" (Beere, 1995b, p. 243). By surveying undergraduates about positive dissociative experiences, Pica and Beere, (1995) showed that this is not only certainly possible, but relatively common. In fact, their study reported that 36.7% of the participants endorsed dissociative symptomology in regards to positive experiences, most commonly in experiences involving sports, sex, prayer, nature, favorable news, acting, hobbies, and music.
Sports. AlteredÂ states of consciousness resembling DP/DR experiences are common in sports. Using interview techniques, Ravizza (1977) researched the personal experiences of athletes involved in various sports such as golf, swimming, track and field, jogging, surfing, and skiing. Several of the athletes' descriptions of their experiences revealed similarities to DP/DR. They reported experiencing totalÂ absorptionÂ in the task or activity, time and space disorientation, Godlike feelings, ego loss and feeling at one with the universe. Further evidence of dissociation during sporting events comes from Sterlini & Bryant's (2002) investigation of dissociation in novice sky-divers. In their study, they found that during their first skydive about 30% of the participants experienced distortions of time and derealization. As in cases of overwhelming joy sports related dissociation seems to result from the narrowing of perception that isolates background components.
Positive Drug Experiences. Use of alcohol and other drugs is often motivated by the desire to produce positive or pleasurable moods. Many drugs, besides inducing an emotional state of well-being or euphoria, can alter the sense of self and induce depersonalization and/or derealization (Mathew et al., 1999; Raimo et al., 1999; Vollenweider et al., 1998; Vollenweider et al., 1999). One reason many people might find alterations in the sense of self following drug use subjectively pleasant is a reduction of self-awareness. Often, the state of self-awareness is aversive, and thus, people may seek to escape or minimize it (Duval & Wicklund, 1972). According to the self-awareness reduction model (Hull, 1987) part of the appeal of consuming alcohol or drugs is that it reduces self-awareness, thereby enabling people to forget their troubles. Baumeister (1991) has further observed that certain forms of bliss seem to be facilitated by a loss of self-awareness, and so a loss of self-awareness may be an intrinsically pleasant, desirable state. Indeed, the term ecstasy meansÂ literally to "stand outside oneself".
Meditation. Depersonalization is a common accompaniment of meditation. There is general consensus the subjective experience of the meditative trance transcends time and space and is associated with bliss (Kasamatsu & Hirai, 1969; Anand, Chinna, & Singh, 1969; Mathew, 2001). Most meditation practioners look forward to the depersonalization experience and find it pleasurable (Good, 1989; Castillo 1990).
Sensory deprivation. Sensory deprivation refers to any major reduction in the amount or intensityÂ of sensory stimulation. When faced with sensory deprivation, people sometimes experience DP/DR symptoms (Reed & Sedman, 1964). Intense or prolonged sensory deprivation is stressful and disorienting. Yet, brief periods of restricted sensation may have beneficial effects by inducing deep relaxation (Suedfeld & Borrie, 1999). Like meditation, people who undergo mild sensory deprivation often look forward to the depersonalization and associated sense of peace.
Hypnotic induction. Treatment using hypnosis, especially self-hypnosis, may help a person learn to deflect depersonalization symptoms by replacing them with pleasant imagery. The experience of dissociation, which is a feature of the hypnotic trance, may be used to "demonstrate to such patients how to control dissociation and to begin a process of communication which, in the context of well structured psychotherapy, can eventually lead to a reduction in such spontaneous dissociative symptoms" (Spiegel 1988, p. 911). Other relaxation techniques (e.g., biofeedback) may also be helpful.
Hypnogogic and Hypnopomic states. Hypnogogic and hypnopompicÂ states refer, respectively, to the states just before falling asleep and just before waking up. It is common for people who are in the transition zone between sleep and wakefulness to experience a general increase in depersonalization (Steinberg, 1994). Most people commonly report some discomfort associated with this depersonalization.
Fatigue and sleep deprivation. Prolonged fatigueÂ andÂ sleep deprivationÂ are additional factors that may cause DP/DR (Bliss et al. 1959). Most sleep deprivation subjects experience a general rise in irritability and cognitive impairment. More dramaticÂ effectsÂ occur with prolonged and severe sleep disturbance,Â such as disorientation, perceptual hallucinations, paranoia, and distortions in perception ofÂ time and self (Oswald, 1970). Sleep deprivationÂ produces marked impairments of "temporal memory" (memory for when events occur) (Harrison & Horne, 2000; Morris, Williams, & Lubin, 1960). In general,Â dissociations in memory for temporal order could have a significant impact on the sense of self by impairing the capacity to represent the self as continuing through time, whose past experiences are seen as belonging to its present self (Klein, 2001). It follows that impairments in self-continuity should produce, to varying degrees, impairments in the sense of personal agency.
Loss of agency feelings. The experience of lacking a sense of agency (i.e., the belief that you are the cause of your thoughts and actions) occupies a central role in the phenomenology of depersonalization (Mellor, 1988; Saperstein, 1949; Sierra, 2009). The low arousal placement of "loss of self-agency" is arguably problematic because fear typically accompanies the sense of not being in control of one's actions and fear is a moderate to high arousal affective state. The position on the circumplex, however, intends to bring together the joint association of "passivity," which is a low arousal emotion concept that clinically relates to an abnormal sense of agency. Thus, while "fear" is a high arousal emotion concept often co-occurring with the loss of self-agency it may be that fear manifests only when crossing critical thresholds in the sense of losing control. More commonly, the loss of self-agency is associated with "numbed passivity".
Self-focus. One of the many metaphors used by depersonalized people is that they are outside their bodies, viewing themselves from a distance. Depersonalization involves an unpleasant hyperawareness of one's self resulting from a split between the observing and experiencing self. Sass (e.g., Sass, 1994) explored this split when discussing an abnormal intensification of self-focus or "hyperreflexivity". Due to a continual self-observation and compulsive self-analysis, the normal integrated whole of our experiences can be split apart. The resulting predicament involves an erosion of practical connectedness to the world, a fragmentation and loss of experienced functionality, an alienation from one's own body and a retreat to a somewhat solipsistic experiential realm, far removed from the social reality that we normally presuppose as a backdrop to our lives. As Parnass and Sass (2001, p. 105) put it, "the patient does not feel being fully existing or alive, fully awake or conscious, or fully present and affected". Her perception is "not lived but is more like a mechanical, purely receptive sensory process, unaccompanied by its affective feeling-tone". It is against the backdrop of this altered experiential realm that depersonalization/derealization is cultured.
Stress and Crisis. Stressful live events or continuing stressors in one's life may lead to the transient symptoms of DP/DR. Indeed, stress is one of the most commonly cited triggers of DP/DR (Aderibigbe, Bloch, and Walker, 2001). Why does stress increase DP/DR? One reason is that psychologicalÂ stressÂ regularly results in heightenedÂ self-focus. In stressful environments, self-focus tends to directÂ attentionÂ towardÂ discrepancy between preferred and actual self-standards (Wells & Matthews, 1995). The fact that stressÂ correlates with DP/DR may also be due to the consequences of disruptive life events on future-orientation. A fundamental component of one's sense of self is one's sense of subjective time (Melges, 1982). Because humans are basically goal-directed, a firm grip on the personal future-through a focus on approaching a desiredÂ or ideal state-provides a key anchoring point for the continuity of temporal perspective. Many life eventsÂ denoted "stressful" (e.g., death of a loved one, divorce, financial or job difficulties) are thoseÂ that cloud the personal future and the direction of temporal perspective, thereby undermining the sense of identity. Â
Altered Perceived Causality. The phenomenology of depersonalization/derealization has some resemblance to that of schizotypal personality disorder or schizophrenia (Simeon & Hamilton, 2008). This phenomenological similarity between DP/DR and schizotypy may be accounted for by magical thinking (i.e., deviations in cause-effect relationships). Content measures developed to assess magical thinking in schizotypy have long recognized the connection between magical thinking and unreality experiences (Gruzelier & Doig, 1996). Altered perceived causality is also markedly present in other types of "anomalous experiences" such as déjà vu and religious or spiritual experience (Main, 2007), both of which have been associated with reports of DP/DR (Myers & Grant, 1972; Trueman, 1984). The odd and intriguingÂ nature of anomalous experience tends to produce profound personal effects on the experiencer. These effects include distress, agitation, and even paranoia due to the presence of an unexplained experience (Freeman & Freeman, 2008; Kennedy and Kanthamani, 1995).
Extreme Threat. It is well established that fleeting experiences of DP/DR are commonplace among people facing life-threatening situations (Mayer-Gross et al., 1969; Noyes & Kletti, 1977). There are two explanations to explain the high prevalence of DP/DR during life-threatening situations. One of them suggests that depersonalization represents a preformed response of the brain to defend against threat. In this theory depersonalization is a detached state resulting from a "hard-wired" biological defense mechanism which evolved to minimize the potentially debilitating effects of extreme anxiety in threatening situations (Sierra & Berrios, 1998). A second view (Beere, 1995a, 1995b, 2009) contends that specific dissociative reactions (depersonalization, derealization, disembodiment, and detemporalization) can occur because when a trauma is startling, perception fixes to the startling figure. In this situation, even though perception focuses on the world, the world's background, according to this hypothesis, is lost since perception focuses narrowly on the threat. According to this view, DP/DR is a non-specific dissociative state devoid of any protective function. Indeed, as discussed earlier, contrary to the "protective" view of depersonalization the presence of acute dissociation also occurs in positive situations (Pica & Beere, 1995).
Hyperventilation. Hyperventilation is another manifestation of arousal and often occurs in combination with anxiety and panic. Hyperventilation is an incorrect way of breathing either too rapid or too deep. When you breathe too fast or too deep then necessary, your body will inhale too much oxygen and this will cause the carbon dioxide levels in the body to drop. As a response the body will narrow the blood vessels which will create symptoms such as headache, dizziness, confusion and increased heart rate. Hyperventilation can also cause a sense of depersonalization and derealization (Lickel, Nelson, Lickel, & Deacon, 2008). Overbreathing and hyperventilation are a normal and automatic response when we are anxious. They are protective devices signaling a threat. Hyperventilation may in part explain correlations between DP/DR and panic (Barlow & Craske, 1988).
Negative drug experiences. Drug use can cause a potentially negative feeling of DP/DR, particularly after large doses or during the first few exposures to the drug. Literature has not neglected this distressing impact. Empirical studies clearly document that cannabis heightens depersonalization (Mathew et al., 1999). Depersonalization induced by marijuana correlated with anger, tension, and confusion, suggesting the experience had negative components (Mathew et al., 1999). Although low "recreational" doses of THC may produce effects that are euphoric, in high doses THC can induce psychotomimetic effects that are similar to that of LSD, except there are less perceptual alterations with THC (Melges et al., 1974). These effects can be terrifying, especially if the person experiences feelings of loss of control. Melges and colleagues (1970a) were the first to report that THC induces "temporal disintegration," or a disorganization of sequential thought and impaired goal-directedness. This phenomenon stems partly from impaired immediate memory. Melges and colleagues (1970b) also showed that depersonalization is closely associated with the degree of temporal disintegration. Thus it appears thatÂ temporalÂ disintegrationÂ is fundamentally involved in the precipitation ofÂ depersonalization. People may experience disintegration of the temporal sequence of thought as aÂ lossÂ in theÂ sense of agencyÂ and a senseÂ ofÂ loss of control. These reactions generally involveÂ anxiety, paranoia, and panic.
In summary, overallÂ the literature review and visual inspection of the two-dimensional space in Figure 1 provide evidence that the valence and arousal dimensions describe two essential characteristics on which the 16 DP/DR precipitators vary. Except for one precipitator, loss of self-agency-which can theoretically relate to either high arousal (e.g., "panic") or low arousal (e.g., "passivity")-the organization of the DP/DR precipitators in the two-dimensional space appear properly placed and provide strong support for the validity of the obtained valence and arousal dimensions.
Implications of the Model
The present taxonomy serves several useful functions. Among these are its ability: (a) to capture the multifaceted nature of DP/DR, (b) to clarify normal and abnormal DP/DR, and (c) to identify needed areas of research and conceptual development.
The Multifaceted Nature of Depersonalization/Derealization
First and foremost, the present results suggest that feelings of unreality should not be construed as a unitary construct. It is an umbrella term for alterations of consciousness in various contexts. Specification of types of depersonalization/derealization is important because, as the review results indicate, the affective implications of DP/DR depend not only on the subjective intensity of DP/DR, but also, and maybe more importantly, on the type of DP/DR. The findings of this review suggest that people who experience similar symptom intensity may experience different emotional consequences. For example, when people depersonalize during overwhelming joy, they are more likely to experience positive affect, whereas when they depersonalize during extreme threat, they are more likely to experience anxiety. Thus, depersonalization has different affective implications depending on the context.
The fact that depersonalization/derealization experiences vary significantly across situations and contexts and that there is significant variability in the relationship of DP/DR to affect strongly supports the presence of severalÂ qualitatively distinct forms of depersonalization/derealization. Research (Simeon et al., 2008) on depersonalization symptom clusters has identified five distinct and interrelated symptoms clusters: (1) numbing; (2) unreality of self; (3) perceptual alterations; (4) unreality of surroundings; and (5) temporal disintegration. Although research into symptom clusters may allow for a better description of depersonalization, it is important to realize that these terms are still broadly basedÂ phenomenological descriptorsÂ that can cover an open-ended number ofÂ situations and framings. The circumplex structure of depersonalization/derealization depicted in Figure 1 thus improves on existing classification efforts by going beyond discussions of symptom clusters (Sierra et al., 2005; Simeon et al., 2008) to the underlying causes of the symptoms. In whatever fashion complaints and symptoms are grouped, attributing them to causes, wherever possible, is of critical importance. Evidently, understanding and being able to treat depersonalization/derealization disorder, as with other mental disorders, necessitates knowing its causes, contents, and consequences, including the causal links between these causes and the observed "symptoms."
In sum, considering depersonalization/derealization as a multifaceted construct necessitates a comprehensive examination of the intricate causal relationships and processes between DP/DR and affective, cognitive, and behavioral constructs. Several of the results of the review highlight the importance of specifying factors of DP/DR that moderate its relationship with negative affect. Given these findings, it is imperative that researchers take a multifaceted contextualized approach to the study of DP/DR.
Normal and Abnormal Depersonalization/Derealization
Second (and more important relative to the discussion), the taxonomy presented here allows for clarifying thinking about normal and pathological DP/DR. To return to the question posed at the beginning of this article: Why is the common occurrence of transient DP/DR perpetuated in some people but not in others? The results of this review suggest the question is, in some sense, invalid. Simply stated, it depends on the false assumption that the persistence of DP/DR relates to the same underlying "symptoms" as those experienced in transient episodes; that the "symptoms" of DP/DR in question (e.g., "unreality feelings") do not themselves essentially differ in their affectiveÂ (or, more generally,Â qualitative) dimension. In fact, however, DP/DR symptoms refer to a broad range of experiences reflecting an altered sense of self or consciousness. Thus, the divergences between normal and pathological DP/DR are not divergences at all, but simply arise from the fact that pathological DP/DR has key distinguishing features and involves processes that are qualitatively distinct from normal DP/DR. A more accurate question, then, is: What are the key distinguishing features and causal processes involved in pathological DP/DR?
Steinberg (1994) has noted that although some aspects of "normal" and "pathological" depersonalization are shared (i.e., feelings of unreality, detachment, strangeness), the quality of pathological depersonalization has key distinguishing features. Steinberg has noted the distinguishing feature of pathological depersonalization is a dissociation between an "observing" and "experiencing" self. Normal depersonalization, however, appears to be a transient alteration of consciousness with no dissociation between an observing and experiencing self. The experiencing self or "participating" self is composed of body, thoughts, feelings, memories, and emotions. The observing self is experienced as a separate, uninvolved "witness" of the experiencing self, with the perception that all of the normal aspects of personality are somehow unreal and do not belong to the observing self. There is the sense of being split off from one's experiencing self and "watching" that self behave. Steinberg's research suggests that it is both the persistence and the nature of depersonalization that differ from normal to abnormal subjects. Other authorsÂ have also proposed to distinguishÂ dissociation between an observing and experiencing self from other symptoms of depersonalization (Putnam, 1997; Van der Hart et al., 2004).
InÂ Figure 1, only twoÂ precipitators may refer to the dissociation between an observing and experiencing self: 1) self-focus, and 2) loss of agency feelings. Additionally, these two precipitators relate to one another as unique qualities of human self-awareness.Â First, the reflexivity of self-focus entails a split into an observing and experiencing self. Second, self-reflectiveness (i.e., a split into an observing and experiencing self) is a distinctly core human feature of agency, which means that people are not only agents of action but also engage in conscious self-examining of their own functioning. Agents have the metacognitive capacity to reflect on themselves and the adequacy of their thoughts and actions.
Table 1 is a modified versionÂ of a classification of depersonalization precipitants along the normal/abnormal continuum, which was presented by Steinberg (1994). As factors that uniquely predict dissociation between an observing and experiencing self, Table 1 identifies self-focus and loss of agency feelings as distinctive features of abnormal depersonalization.
Table 1: Comparison of normal and abnormal depersonalization
[See Table 1]
Note: Pathological depersonalization/derealization is not expected to correlate with the precipitating factors listed in Column 1. It may, however, be precipitated by factors listed in Column 2 (e.g., stressful live events, altered perceived causality).
Needed Areas of Research and Theory
The present taxonomy helps identify areas of theoretical and empirical deficiency. Most notable are questions stemming from the relationship between dissociation andÂ affect. Dissociation is believedÂ toÂ serve a protective function by allowing people to avoid experiencing the emotional impact of extreme threat. However, in their paper "Depersonalization Disorder:Â DissociationÂ and Affect,"Â Simeon et al. (2003) describe study results suggesting that dissociation does not serve a protective function as it sometimes does with other dissociative disorders. Patients with depersonalization/derealization disorderÂ (DP/DR-D) actuallyÂ suffered from chronic elevations in frequency and intensity ofÂ negative affect as compared to control participants. Alternatively, it may be argued that the correlation between DP/DR and chronic elevations of negative isÂ explained by self-focus. Patients with DP/DR-D can be characterized by a tendency to strongly introspect and reflect on their self, that is, an increased self-focus. Clinically, this increased self-focus has been implicated as a major cause of negative affect (Ingram, 1990).
Despite the well-known role self-focus plays in DP/DR-D, the underlying mechanisms remain unclear. Thus, a priority for future research should be the systematic examination of the self-focused attention process within DP/DR-D. Toward this end, much has been written about the necessity of understanding self-focused attention as part of an overall self-regulatory process (Carver & Scheier, 1998; Pyszczynski, Greenberg, et al., 1991). Carver and Scheier (e.g., 1986, 1990, 1998) suggested that self-focus plays a role in a self-regulatory cycle that helps people in the pursuit of goals. In this self-regulatory process, people compare their current standing with a particular salient self-standard and determine whether they are meeting this standard. If the current self matches the desired standard, the person terminates the regulatory process. If, on the other hand, progress toward the standard is slow or the discrepancy between the current self and the desired standard seems impossible to bridge, negative affect results. One context in which this discrepancy is particularly salient is negative life events such as failures and losses. Carver and Scheier (1998) also discussed the bidirectionality of the relationship between self-focused attention and negative affect and the role negative affect plays in drawing attention to the self.
The multifaceted nature of DP/DR has implications not only for affective processes but also for other behavioral and cognitive correlates and consequences. One might reasonably ask how DP/DR impacts cognition and behavior: Does DP/DR focus one's cognitions on existential concerns surrounding one's consciousness (e.g., likeÂ René Descartes' arguments for deception by dreaming or anÂ evil demon, or the popular brain-in-a-vat scenarios)? Are such cognitions more likely to form against the backdrop of behavioral disengagement or withdrawal? Are certain cognitive correlates of DP/DR associated with increased risk-taking (e.g., believing that one is immortal)? Similar to research on the affective correlates of DP/DR, research has largely ignored these behavioral and cognitive correlates.
Another topic needing moreÂ thorough attention is the relationship between DP/DR and altered perceived causality. Humans appear to have an innate biological need to seek out causality, with the brain functioning in such a way that it seeks to find possible causal relationships between events (D'Aquili & Newberg, 1998; Beitman, 2009). Yet the inability to filter out irrelevant causal relationships and sensory stimuli from the environment can lead to sensory overload and an array of psychotic symptoms as indicated by ideas of reference, odd beliefs, and magical thinking (McGhie & Chapman 1961; Venables 1964). It is possible thatÂ DP/DR during the prodromal and acute phase of schizophrenia (KlosterkÓ§tter et al., 2008) is related toÂ the similar, if not identical, character of altered perceived causality and unreality experiences, and this topic certainly deserves further exploration.
Finally, future research shouldÂ attempt to establish (causal) relationshipsÂ
among the more or less standard set of DP/DR precipitators. In other words, how do the different DP/DR precipitants interact? Various combinations of precipitators may have a synergetic effect, with one increasing the potential intensity of the other. In essence, the interacting variables need to be modeled for clearer theoretical interpretation. This points to the need for new treatment models that specifically address the processes engaged in DP/DR phenomena.
The terms "depersonalization" and "derealization" have been used to describe a wide range of psychological phenomena. The cognitive conception of depersonalization/derealization describes it as a unitary phenomenon, with only cognitive appraisals distinguishing between normal and abnormal DP/DR. However, the available evidence is more consistent with a model that identifies underlying differences between DP/DR experiences along the dimensions ofÂ valence and arousal. This paper supports the conception of abnormal DP/DR as having unique qualities, namely, a dissociation between an observing and experiencing self that is precipitated by intense self-focus and loss of self-agency. It is hoped that this review will contribute not only to a better understanding of depersonalization/derealization but also to the continued development of the understanding of normal and abnormal functioning.