Explain why enduring personality change after a catastrophic experience is described as producing two different characteristic pictures depending on its trigger.

Following a catastrophic external experience, the picture is usually one of social withdrawal, combined with a hostile or mistrustful attitude to the world, alongside feelings of hopelessness, estrangement, and a chronic sense of being constantly on edge or under threat. Following a severe episode of psychiatric illness instead, the picture is more often one of dependency, a demanding attitude toward others, reduced interests, passivity, and persistent claims of illness, together with low mood and impaired occupational and social functioning. These two pictures differ because the underlying process is thought to differ: a direct, threat-related response to external catastrophe produces a defensive, mistrustful stance toward the world, while the experience of severe illness itself, with its associated dependency on others and disruption to functioning, produces a more passive, illness-focused, dependent pattern instead, even though both are grouped under the same diagnostic entry because they share the core feature of a genuine, lasting post-event change in character.