Happy Hungary's neighbour heads off incendiary madness (9)

I believe the answer is:

pyromania

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'happy hungary's neighbour heads off' is the definition.
I can't judge whether this defines the answer.

'incendiary madness' is the wordplay.
'incendiary' becomes 'pyro' (I can't explain this - if you can you should believe this answer much more).
'madness' becomes 'mania' (I've seen this before).
'pyro'+'mania'='PYROMANIA'

Can you help me to learn more?

(Other definitions for pyromania that I've seen before include "Flaming madness!" , "Pay Marion (anag.)" , "Obsessive interest in fire" , "Obsession with burning things" , "criminal tendency" .)

I've seen this clue in the Sydney Morning Herald.

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