Is it permissible for a Muslim facing many insoluble problems to invoke death upon himself for relief?

It is disliked for a Muslim to wish for death due to worldly harm, because it deprives him of the good of obedience and the opportunity to repent. Also, a believer's life only increases him in goodness, and the harm might increase after death. Two cases are exceptions to this: fear of temptation (fitna) in one's religion, and seeking martyrdom in the way of Allah due to its immense virtue.