Paraphrenia is a mental disorder characterized by an organized system of paranoid delusions with or without hallucinations (the positive symptoms of schizophrenia) and without deterioration of intellect or personality (its negative symptom). This disorder is also distinguished from schizophrenia by a lower hereditary occurrence, less premorbid maladjustment, and a slower rate of progression. Onset of symptoms generally occurs later in life, near the age of 60. The prevalence of the disorder among the elderly is between 0.1% and 4%.