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PeerJ. 2018 Apr 3;6:e4569. doi: 10.7717/peerj.4569. eCollection 2018.

No tears in heaven: did the media create the pseudo-phenomenon "altitude-adjusted lachrymosity syndrome (AALS)"?

Author information

PatientsLikeMe, Cambridge, MA, United States of America.
Cohen Veterans Bioscience, Cambridge, MA, United States of America.



In the media, numerous public figures have reported involuntary emotional outbursts arising from watching films on planes, resembling neurological phenomena such as pseudobulbar affect. Putative risk factors put forward include altitude, mild hypoxia, or alcohol. Our objective was to determine whether watching a film on an airplane is really more likely to induce involuntary, uncontrollable, or surprising crying than watching one on the ground, described in some social media as "altitude-adjusted lachrymosity syndrome" (AALS), or whether this is a pseudo-phenomena.


Amazon Mechanical Turk survey participants (N = 1,084) living in the United States who had watched a film on a plane in the past 12 months were invited to complete an online survey. The main outcome measures were likelihood of crying in a logistic regression model including location of viewing, age, gender, genre of film, subjective film rating, annual household income, watching a "guilty pleasure" film, drinking alcohol, feeling tired or jetlagged, or having a recent emotional life event.


About one in four films induced crying. Watching a film on a plane per se does not appear to induce involuntary crying. Significant predictors of crying included dramas or family films, a recent life event, watching a "guilty pleasure", high film ratings, and female gender. Medical conditions, age, income, alcohol use, and feeling tired or jetlagged were not significant.


People reporting the pseudo-phenomena of AALS are most likely experiencing "dramatically heightened exposure", watching as many films on a plane in a week's return trip as they would in a year at the cinema. Such perceptions are probably magnified by confirmation bias and further mentions in social media.


Aeronautic medicine; Crying; Emotion; Internet; Overdiagnosis; Pseudobulbar affect; Social media

Conflict of interest statement

PW is an employee of PatientsLikeMe and holds stock options in the company. LL is an employee of Cohens Veterans Biosciences. PW is an associate editor at the Journal of Medical Internet Research and is on the Editorial Boards of The BMJ, BMC Medicine, and Digital Biomarkers. The PatientsLikeMe Research Team has received research funding (including conference support and consulting fees) from Abbvie, Accorda, Actelion, Alexion, Amgen, AstraZeneca, Avanir, Biogen, Boehringer Ingelheim, Celgene, EMD, Genentech, Genzyme, Janssen, Johnson & Johnson, Merck, Neuraltus, Novartis, Otsuka, Permobil, Pfizer, Sanofi, Shire, Takeda, Teva, and UCB. The PatientsLikeMe R&D team has received research grant funding from Kaiser Permanente, the Robert Wood Johnson Foundation, Sage Bionetworks, The AKU Society, and the University of Maryland. PW has received speaker fees from Bayer and honoraria from Roche, ARISLA, AMIA, IMI, PSI, and the BMJ.

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