Rick gets into records with unknown disorder (8)
I believe the answer is:
epilepsy
'disorder' is the definition.
(epilepsy is a kind of disorder)
'rick gets into records with unknown' is the wordplay.
'rick' becomes 'pile' (rick can mean a pile or stack of hay).
'gets into' means one lot of letters goes inside another.
'records' becomes 'EPs' (EP is a type of record).
'with' says to put letters next to each other.
'unknown' becomes 'y' (algebra).
'pile' going inside 'eps' is 'epileps'.
'epileps'+'y'='EPILEPSY'
(Other definitions for epilepsy that I've seen before include "Disease of nervous system" , "Nervous disorder causing convulsions and fainting" , "affliction" , "Convulsive disorder of the central nervous system" , "Disorder marked by convulsions" .)