Like blood elves, high elves can use arcane magic, but most do not because most high elves are not spellcasters. Whether or not they are spellcasters, all high elves are suffering acute pangs of withdrawal in the absence of the Sunwell's energies. A few high elves here and there have realized the cause of their distress; others have not.
[...]
Such a low rate of attrition might be considered an argument in favor of simply forgoing magic and suffering through the consequences. Indeed, a few high elves are said to have succeeded in taking this route through sheer willpower: they survived the process, however unpleasant. Apparently certain magical artifacts also ameliorate the symptoms of withdrawal and might, if sufficiently powerful, be able to suppress them altogether. (
WC Encyclopedia)