How do you get paranoia?

I know a women suffering from paranoia. She is my friends wife. her husband is an state govt employee. after a repeated request application given to the govt for govt quarter , finally he got the quarter. two months of their happy family life in the flat one day their neighbour women ask her to yesterday there was a sound of feet at nine thirty in the neight. who was he, my friend was at night duty on that day he was no t available at that night. this question was confussed her. why she ask a question to me. i am a innocent i love my husband very well as an Indian she never do such thing in the whole life. then after her thinking is increased day by day and cause paranoia. they press her husband to report a petion to the police. her husband file a petion a petion to police and police enquire done on that day when police gone after the qnquiry that women try to suicide. but somebody escaped. then after her relatives came the flat and feared my wife. now a days she very well in the home but whenever she going out side she told her husband some body is follow me some vvip car is is also follow me in the home she is quite ok but problems came only going out side not only the same place but long distance when she travel with his relatives then also told that some body follow me it is therefore i think that neighbpouring wpomen question is the cause by kacko my email is alexanderkacko@yahoo.com please reply me as soon as possible