Based on the assumption that the human mental model of reality is grounded in a dichotomy between a self-model and a world-model, four basic classes of exceptional phenomena (ExP) can be postulated. In terms of their location, ExP may appear as internal phenomena within the self-model or as external phenomena within the world-model. Regarding their relational nature, ExP can manifest as coincidence phenomena, representing unusual connections between elements of the self-model and the world-model, or as dissociation phenomena, representing unusual separations. In principle, all exceptional experiences (ExE) can be traced back to ExP belonging to one or more of these four basic classes. Derived from this theoretical framework, the “Questionnaire on the Phenomenology of Exceptional Experiences” (PExE) was developed and has been used in its revised form (PExE-R) in counseling settings since 2011. It assesses the frequency of ExP within the four basic classes, their temporal occurrence, situational context, and sociodemographic data.

In 2017, a comparative study was conducted using six samples: ExE clients, university students, the Swiss general population, individuals with near-death experiences, meditators, and a sample from the United States (Fach, 2024). Results showed that the frequency of ExP among clients was roughly twice as high as in the general population. Even higher frequencies were reported by individuals with near-death experiences and by meditators.

Figure 1 shows the mean values for each basic ExP class on a five-point frequency scale ranging from “never” (0) to “very often” (4). On average, ExP frequency among clients was about 50% higher than in the general population. Those seeking advice also rated their ExE as significantly more meaningful for their lives and described them more often as both “positive and enriching” and “negative and distressing”— an ambivalence not observed in the general population. Across all groups, the external circumstances showed minimal differences: the reported phenomena occurred primarily during waking consciousness and spontaneously. The fact that ExE occur not only among help-seeking individuals, but also—albeit less frequently—in the general population, supports the notion that ExE are generally widespread and continuously distributed in terms of frequency and intensity. Only at higher levels do ExE become associated with psychological distress or mental health issues. That near-death experiencers and meditators, despite reporting even more frequent ExE, typically rate them positively and experience little or no distress, speaks against equating ExE with psychopathology. Clearly, other factors come into play for clients (see Clinical Parapsychology).

Although the frequency of ExE varies across different samples, the relative proportions of the four basic ExP classes are consistently similar: coincidence phenomena are the most frequent, followed by internal and external phenomena (roughly equal in occurrence), while dissociation phenomena are the least common. The U.S. sample provides initial evidence that findings from the German-speaking countries may be transferable to non-European contexts. The fact that ExP, despite varying frequencies across populations, retain consistent proportional distributions across the basic classes suggests a universal dimensionality of ExE.

Based on the comparative sample, the PExE-R was validated and subsequently revised. The updated PExE-II includes a reduced item set and introduces a global ExE scale, comprising the four subscales externality, internality, coincidence, and dissociation, each consisting of five items. The response format uses a newly adjusted five-point frequency scale from “never” (0) to “often” (4). Item and scale analyses show psychometric properties and reliability coefficients that meet standard criteria in psychological test diagnostics. The construct validity has since been confirmed by additional international studies. In collaborative efforts, the PExE-II has been translated into English (Christine Simmonds-Moore, University of West Georgia), French (Renaud Evrard, University of Lorraine), Italian (Patrizio Tressoldi, University of Padua), and Spanish (Yolanda Alonso, University of Almería). The dimensionality of the four ExP basic classes was replicated across all samples. Figure 2 presents the mean scores from the PExE-II studies. Notably higher values in France and Italy compared to German samples are attributed to participant recruitment via ExE-affiliated online forums. Regardless of frequency differences, the familiar pattern of ExP class distribution was observed. An exception was the sleep paralysis sample, in which dissociative ExP occurred more frequently, as expected. Future studies will need to examine whether the proportional structure of ExP classes applies beyond European and Western cultures.