is patient 96404 ever prescribed senna during the previous year?
select count(*)>0 from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 96404 ) and prescriptions.drug = 'senna' and datetime(prescriptions.startdate,'start of year') = datetime(current_time,'start of year','-1 year')