Youmayknowthefeeling.It’sthelateafternoon,andyoustillhaven’tleftthehouse.You’vespentseveralhoursonyourphone,scrollingthroughyourFacebooknewsfeed,refreshingTwitterandwatchingYoutubevideos.Asmartphonemightfeellikeit’skeepingyouconnectedbutitcanalsobeawayofsecludingyourself. DatafromarecentstudyconductedbyresearchersatNorthwesternUniversity’sFeinbergSchoolofMedicinefoundthatthescenariodescribedabove—highvolumeofphoneuseandastaticgeographiclocation—couldbelinkedtodepression.ThestudypublishedinTheJournalofMedicalInternetResearch,alsofoundthatdepressedpeople,onaverage,spendmoretimeonthephonethannon-depressedpeople. “Peoplearelikely,whenontheirphones,toavoidthinkingaboutthingsthataretroublingpainfulfeelingsordifficultrelationships,”saidDavidMohr,oneofthestudy’sseniorauthorsandaprofessorofbehavioralpsychologyatNorthwestern,inastatement.“It’sanavoidancebehaviorweseeindepression.”Mohralsopointedoutthatdepressedpeopletendtowithdrawemotionallyandavoidgoingout—behaviorsthatarearguablyfacilitatedbytheconstantentertainmentstreamavailableonsmartphones. Thestudy’sparticipantsconsistedofamixofpeoplewithandwithoutpriordepression.Theycompletedaquestionnairedescribingtheirsymptomsbeforeagreeingtohavetheirphoneusemonitoredfortwoweeks.UsingGPS,theresearcherstrackedtheirlocationandtheamountoftimetheyspentonthephone.Theywerethenabletoidentifywhichparticipantsweredepressedusingtheaggregatedphonedata,with87percentaccuracy. SohrobSaeb,aresearchfellowatNorthwestern,saidinthereleasethatphonescouldbemorereliablefordiagnosingdepressionthantraditionalmethods.Instandardindustrypractice,patientsareoftenaskedtodescribetheirsymptomsbyindicatinghowsadtheyareonascaleof1to10.AccordingtoSaeb,thereleasereported,theseresponsescanberoteandunreliable.Incontrast,thestudyfound,asmartphonecanunobtrusively(不引人注目地)andaccuratelymeasureapatient’sdailyactivity,providingdatathatcouldtriggerahealthcareprovidertorecognizetheneedforanintervention. WhatcanbelearnedfromthestudyconductedbyresearchersatNorthwesternUniversity?