SELECT 
n.nspname AS table_schema,
c.relname AS table_name,
at.attname AS column_name
FROM pg_attribute at INNER JOIN pg_class c ON at.attrelid=c.oid
INNER JOIN pg_namespace AS n ON n.oid=c.relnamespace
INNER JOIN pg_authid AS a ON n.nspowner=a.oid
INNER JOIN pg_type AS t ON at.atttypid=t.oid
LEFT JOIN pg_type AS dt ON t.typbasetype=dt.oid
WHERE (nspname='public' OR rolname<>'postgres')
AND (t.typname='citext' OR dt.typname='citext')
AND c.relkind='r' 
AND at.attisdropped='f'
AND at.attnum>0
ORDER BY table_schema, table_name, column_name;