(string) connection unexpectedly closed (timed out?)

Query: SELECT SUBSTRING_INDEX(GROUP_CONCAT(keyword), ',', 8) AS related_terms FROM search_popular WHERE (keyword LIKE 'pee panties%' OR keyword LIKE 'pee%' OR keyword LIKE 'panties%') AND keyword != 'pee panties' ORDER BY hits DESC LIMIT 8
Error Message: MySQL server has gone away
Error Number: 2006