Uncontrollable excitement breaking out this year? (8)
I believe the answer is:
hysteria
'uncontrollable excitement' is the definition.
(I've seen this before)
'breaking out this year?' is the wordplay.
'breaking out' is an anagram indicator.
'this'+'year'='thisyear'
'thisyear' is an anagram of 'HYSTERIA'.
(Other definitions for hysteria that I've seen before include "Problem of the uncontrolled" , "Uncontrolled emotion" , "Delirium - nervous disorder" , "display of wild emotion" , "Panic" .)