Azkaban has a reputation of evil and fear throughout the series. As mentioned at the start of the series, Azkaban is guarded by the Dementors, working under the Ministry of Magic. The large presence of Dementors renders the inmates incapable of happiness and forces them to relive their worst memories, as they become gradually helpless and often severely insane. According to Sirius, many inmates simply stop eating and eventually die of starvation. Sirius' reasoning for this is that "They simply lose their will to live". As Dementors are extremely difficult to injure – the only spell effective against them is the Patronus Charm – Azkaban was long considered impossible to escape from, until Sirius escaped (although Barty Crouch Jr had previously broken out with the help of his parents); however, Dumbledore claimed he could break out of Azkaban if he wished to do so.