Final answer:
The sentence should use the term 'diathesis-stress model' to accurately illustrate that both genetic predisposition and environmental stress contribute to the development of a disorder when an individual is faced with stress.
Step-by-step explanation:
The statement should be changed to reference the diathesis-stress model instead of the "stress model." The corrected sentence will read: "The diathesis-stress model suggests that people with a predisposition for a disorder are more likely to develop the disorder when faced with stress." The diathesis-stress model posits that a combination of genetic predisposition and environmental stress can result in the manifestation of psychological disorders.
According to the diathesis-stress model, individuals have certain vulnerabilities or predispositions (diatheses) for developing a disorder that may be activated under the right conditions of environmental or psychological stress. Not all individuals with a predisposition will develop a disorder; it is the interaction between the diathesis and stress that increases the risk.
Therefore, the appropriate change to the sentence to reflect the correct terminology and concept would be to include "diathesis-" in front of "stress model." This acknowledges that a predisposition for a disorder interacting with stress may trigger the development of that disorder.