Paranoia generally refers to delusional disorders, also known as paranoid disorders, with a slow course and no strict clinical 10 precursors to paranoia. Delusional disorders are a group of psychiatric disorders that develop into one or more interrelated delusions and perceptual disturbances as the main manifestation. The etiology is not clear, the manifestations are diverse, there are mostly no obvious precursors, and the diagnosis is difficult, and this abnormal mental state usually lasts for 3 months and more. A family history of delusional disorder, specific personality traits, and social isolation are usually considered to be factors at high risk for the development of delusional disorder. Before the onset of paranoid disorder, some patients may exhibit sensitivity, suspicion, ego and stubbornness, jealousy, lack of trust with others, or may have difficulty falling asleep and decreased sleep quality. As the disease progresses, the abnormal manifestations gradually become obvious, and symptoms such as delusions of victimization, exaggerated delusions, and delusions of love may appear. If one or more delusions are present for a long period of time, lasting at least 3 months, and there is no significant impairment of somatic as well as thinking functions, no behavioral abnormalities or disorders, and the diagnostic criteria for schizophrenia and mood disorders are not met, a possible delusional disorder needs to be considered. In addition, those suspected of having the disease need to be examined in departments such as neurology and to exclude somatic diseases, such as central neurological diseases, hepatic encephalopathy, as well as delirium and dementia that cause delusional manifestations. If there is no organic damage, the whole spectrum of treatment, such as medication and psychological treatment, is required as a mental illness, and the specific treatment depends on the actual examination results and the doctor’s judgment.