Physical factors
The development of paranoia and hallucinations in old age have been related to both auditory and visual impairment, and individuals with paraphrenia often present with one or both of these impairments. Hearing loss in paraphrenics is associated with early age of onset, long duration, and profound auditory loss. History
The term paraphrenia was originally popularized by Karl Ludwig Kahlbaum in 1863 to describe the tendency of certain psychiatric disorders to occur during certain  transitional periods in life (describing paraphrenia hebetica as the insanity of the adolescence and paraphrenia senilis as the insanity of the elders.The term was also used by Sigmund Freud for a short time starting in 1911 as an alternative to the terms schizophrenia and dementia praecox, which in his estimation did not correctly identify the underlying condition, and by Emil Kraepelin in 1912/3, who changed its meaning to describe paraphrenia as it is understood today, as a small group of individuals that have many of the symptoms of schizophrenia with a lack of deterioration and thought disorder. Kraepelins study was discredited by Wilhelm Mayer in 1921 when he conducted a follow-up study using Kraepelins data. His study suggested that there was little to no discrimination between schizophrenia and paraphrenia; given enough time, patients presenting with paraphrenia will merge into the schizophrenic pool. However, Meyers data are open to various interpretations. In 1952, Roth and Morrissey conducted a large study in which they surveyed the mental hospital admissions of older patients.
Recovery from the psychotic symptoms seems to be rare, and in most cases paraphrenia results in in-patient status for the remainder of the life of the patient. Patients experience a slow deterioration of cognitive functions and the disorder can lead to dementia in some cases, but this development is no greater than the normal population. Epidemiology
Studies suggest that the prevalence of paraphrenia in the elderly population is around 2–4%. Sex differences
While paraphrenia can occur in both men and women, it is more common in women, even after the difference has been adjusted for life expectancies. The ratio of women with paraphrenia to men with paraphrenia is anywhere from 3:1 to 45:2. Age
It is seen mainly in patients over the age of 60, but has been known to occur in patients in their 40s and 50s. Personality type and living situation
It is suggested that individuals who develop paraphrenia later in life have premorbid personalities, and can be described as “quarrelsome, religious, suspicious or sensitive, unsociable and cold-hearted.” Many patients were also described as being solitary, eccentric, isolated and difficult individuals; these characteristics were also long-standing rather than introduced by the disorder. Most of the traits recognized prior to the onset of paraphrenia in individuals can be grouped as either paranoid or schizoid. Patients presenting with paraphrenia were most often found to be living by themselves (either single, widowed, or divorced). There have also been reports of low marriage rate among paraphrenics and these individuals also have few or no children (possibly because of this premorbid personality).