Development of a Self-Administered Questionnaire to Detect Psychosis at High Altitude: The HAPSY Questionnaire.

Psychotic symptoms during exposure to high altitude (HA) have been linked to accidents or near accidents on the mountains. It is thus of great importance to directly identify psychotic symptoms in individuals who are exposed to HA quickly and reliably on the mountain, even in the absence of experienced medical personnel. Psychotic features at HA frequently include positive psychotic symptoms such as hallucinations, delusions, or disorganized thinking/speech. The aim of the current study was to develop the first self-administered questionnaire (High Altitude Psychosis [HAPSY] Questionnaire), which individuals may use in the future to self-assess altitude-related psychotic symptoms on the mountain. We utilized two existing self-rating questionnaires for psychotic symptoms (the Psychotomimetic States Inventory, PSI and the Cardiff Anomalous Perception Scale, CAPS) as the basis for a two-round Delphi process. As part of this process, additional statements were suggested by the 40 Delphi participants. Eleven self-administered statements-all of them related to positive psychotic symptoms-were identified to be most useful for the self-detection of HA-related psychotic symptoms on the mountain. This is the first self-administered questionnaire that allows the identification of HA-related psychotic symptoms on the mountain. A subsequent validation study is needed to address the psychometric properties of this questionnaire. Clinical validation will have to be performed in a field study.