What is it called when you make up stories in your head and believing them?

What is it called when you make up stories in your head and believing them? Confabulation is a symptom of various memory disorders in which made-up stories fill in any gaps in memory. German psychiatrist Karl Bonhoeffer coined the term “confabulation” in 1900.

Confabulation is a symptom of various memory disorders in which made-up stories fill in any gaps in memory. German psychiatrist Karl Bonhoeffer coined the term “confabulation” in 1900.