What is a key characteristic of Delusional Disorder?

Delusional Disorder is characterized by the presence of nonbizarre delusions that persist for at least one month. Nonbizarre delusions are those that involve plausible situations, such as being followed, deceived, or having a fatal disease, which could occur in real life. This is distinct from bizarre delusions, which are implausible or impossible. The requirement for the delusions to last for at least one month helps differentiate Delusional Disorder from other conditions, such as Brief Psychotic Disorder or Schizophreniform Disorder where symptoms may be more transient.

In Delusional Disorder, the individual may continue to function relatively well outside of the impact of the delusional beliefs, differentiating it from disorders that cause significant functional impairment. While symptoms may lead to difficulties in certain situations, the overall functioning is not as severely impaired as seen in other psychotic disorders. This makes the duration and the nature of the delusions the cornerstone of diagnosing Delusional Disorder.