What message The Others 2001 movie gives?

The scary movie lovers can't live without watching the amazing movie The Others 2001 ever created in the history of horror genre.I watched it after 7 years after downloading it.
The reason is that whenever I have downloaded or watched any movie,I have always checked the reviews on various forums and it's reviews were superb and astonishing.After watching the whole movie,I was stunned that it was not only masterpiece of horror but also possess a very strange theme.I noticed that that all the family pictured in the house were souls and they were living in mist as punishment because of suicide they commit.
Anybody can tell me that what is the main theme of the movie?