Oh no, how did I manage to lose me? Ahem. I don't know the origin of the phrase, but I'm sure they're doing it. The closest I could find is in “Pamela Cundall, who lived through the Great Depression, said ‘I'm afraid I lost me’ as she had come to the sad conclusion that there was no reason to live”. This could be why there are two different phrases used, to show how her life was changed. But still, no one wants to admit to losing their marbles (or indeed, finding them) and yet we have a phrase, “to lose me”, which tells us that people have lost their minds too. You can lose your mind from a direct hit to the head, or, as seems to be the case in the example, from a prolonged depression. The reason they are losing their minds is because there is no reason for them to. I don't know if this would work, though. Maybe it's a bad idea. Maybe it's just that they are all nuts. A: The phrase you're looking for is "losing one's marbles", which dates back to at least 1879: Marble game, a new form of game played with marbles, having gained a great vogue lately. —“New York Argus”, New York, NY, August 19, 1879 As shown here, the "marbles" referred to are not necessarily a round, hard-shelled type of object, but the original idea comes from the Spanish word for the game Jai alai, which literally means "hit the basket." Jai alai is the name of a game popular in Spain and many Spanish-speaking countries, especially Cuba and Puerto Rico. The game is said to have been brought to Spain by the Moors in the early 1600s. The word derives from the Latin ala for "wing" or "ribbon." — wiktionary.com You'll still find an occasional reference to "losing my marbles," but it is extremely rare today. A: Another related expression is "going off the deep end" (OED). "Deep End: noun the most remote or inaccessible part of the pool or swimming-pool" So when you're swimming and you dive straight to the bottom of the pool and don't resurface for a long time, you've gone (or might have gone) "off the deep end". A: To lose the plot. What was originally meant by this phrase? As with "I'm afraid I lost me", it is unclear to me, as Wikipedia only provides speculative explanations for the phrase's origin. Nevertheless, it seems to be a rather general idiom which I find in both British and American English and which means "to lose one's sense of proportion". The original Oxford English Dictionary entry has this under it's definition of lose the plot: U.S. (humorous) To lose one's reason; to go mad. Used typically of someone whose behaviour is irrational. [1940s+] The oldest citation is from the March 28, 1938 Washington Post. The reference is to the 1933 play The Man Who Came to Dinner (film 1939) and a passage from that show that goes as follows: Olivia. Mr. Burns, you're a very clever man. And you're right. I'm a most frightful little fool. But that's beside the point. You're here on a business mission and I have to do business with you. Burns. Madam, your language is offensive to your sex. Olivia. And it's offensive to mine. Burns. Oh you haven't lost the plot, have you, madam? I'd read about this expression before on the Internet, usually in relation to various other quotes in The Man Who Came to Dinner. The following two sites are fairly good, including what may be relevant quotes from Shakespeare and the bible. http://www.phrases.org.uk/bulletin_board/32/messages/1336.html http://www.thefreedictionary.com/plot It seems to me that the basic meaning is quite clear. Now why is this particular phrase used for "losing the plot"? One obvious explanation might be "losing one's wits" (although this definition would probably be better with off the rail or losing one's bearings or off one's rocker). In this situation, one's sense of what is normal and usual may become disordered, making it difficult to think straight. It could also be that it's "all over the place", like a plot in a movie or a book would be if it wasn't properly organized. The first quote I could find was in a paper written by M.F.K. Fisher. A brief passage from the paper follows: I am one of those who have lost the plot, not as many have done with the aim of recovering it but because, as once happened to a poet, they have gone off the deep end. And again it is mentioned in a dictionary entry on the term "Off the Rails", which might be appropriate here. As is mentioned above, it is possible to be "off the deep end" and still have a "normal" use of language. However, a person might slip between two more extreme and abnormal states: having lost the plot or gone mad. Although this is more a matter of idiom, the phrase "I'm off my rocker" meaning "completely mad" is probably closely related. See this related question on "off the crazy train". (Note that it's also in a novel The Nanny Diaries (1995), from which I took this quote.) A: A very early example of a person "losing the plot" was in a Shakespeare play: Olivia. Mr. Burns, you're a very clever man. And you're right. I'm a most frightful little fool. But that's beside the point. You're here on a business mission and I have to do business with you. Burns. Madam, your language is offensive to your sex. Olivia. And it's offensive to mine. Burns. Oh you haven't lost the plot, have you, madam? This particular instance is from the play The Man Who Came To Dinner (1933). Mr. Burns, you're a very clever man. And you're right. I'm a most frightful little fool. But that's beside the point. You're here on a business mission and I have to do business with you. Burns. Madam, your language is offensive to your sex. Olivia. And it's offensive to mine. Burns. Oh you haven't lost the plot, have you, madam?