I can confirm this with thunderbird 17.0.2 on a 12.10 Kubuntu Version.
The problem was resolved with deactivating the message synchronisation of an IMAP mail account.
My other accounts using POP-Servers don't generate the high CPU usage.
Removin
messages-db.sqlite and global-messages-db.sqlite-journal files.
before has not changed anything.
I can confirm this with thunderbird 17.0.2 on a 12.10 Kubuntu Version.
The problem was resolved with deactivating the message synchronisation of an IMAP mail account.
My other accounts using POP-Servers don't generate the high CPU usage.
Removin messages- db.sqlite- journal files.
messages-db.sqlite and global-
before has not changed anything.