Obtained some information from Google.

Norma's parents were abusive and neglectful.

Her childhood was unhappy, with an abusive alcoholic father and a mother who was "sedated all the time," and also incredibly abusive and manuplitive, much like herself. Maybe even worse than her father.

She's incredibly possessive and protective of her son, Norman Bates. This leads her to emotionally traumatize her son because she's so possessive and manuplitive and never lets him have the time of day.

She teaches that all women, except herself, are whres and flirts. She doesn't want anyone else to even make eye contact with her son.

Norma herself is very traumatized, and perhaps passes on the trauma to her son, and projects the same trauma and mental abuse.

Her and her son, Norman, from before run their motel together and even have a separate house there. Norman's father died, and she ended up stabbing someone to death.

Norman still goes to school, but he still is greatly traumatized from all of the blood and witnessing his mother brutally murder someone.. it is horrifying.