Marilyn is depressed a great deal of the time and seeks from a doctor. she is diagnosed as having a mental illness caused by a chemical imbalance. marilyn is most likely being treated by a person who adheres to the of psychological disorders.

marilyn is most likely being treated by a person who adheres to the Medical model of psychological disorders.
The medical model of psychological disorders will make the assumption that any form of psychological disorders is a direct result of physical problems (such as chemical imbalances or the damage in your brain).

This is true! hope this : ))