Dementia is acquired dementia, an intellectual disorder with a permanent decline in cognitive activity. It manifests in the loss of old skills and the inability to acquire new ones. More often, this form of dementia is observed in old age. Moreover, it often develops in the background of schizophrenic disorders. Let’s find out how and why dementia occurs in schizophrenia.

Dementia in Schizophrenia



Unlike mental retardation, when a person does not develop the psyche or certain aspects of it, dementia is characterized by the breakdown of mental functions that have already been formed. It is caused by diseases affecting the brain. Moreover, the list of pathologies in which dementia develops is pervasive.

According to the World Health Organization, there are more and more people with dementia every year, and in 2015 there were about 46 million of them; in 2017, there were already about 50 million patients registered worldwide. Approximately 7.7 million diagnoses are made each year.

These numbers will increase due to many factors, including increasing life expectancy. It is expected that by 2050 there will be more than 131.5 million people with dementia on our planet.


Relationship to schizophrenia

Must consider two aspects in disclosing the relationship between schizophrenia and dementia. The first is considered in the context of directly acquired dementia, which can develop due to various brain lesions. As practice shows, the risk of dementia in schizophrenia is higher than in people with a healthy mind.

The second aspect is related to schizophrenic dementia, a type of intellectual disability often seen in diseases of the schizophrenic spectrum. Such patients are characterized by dementia without significant organic changes.

It is also called transient dementia when a person has signs of intellectual disability for many years but suddenly finds a well-preserved memory and intellect. Not all specialists consider this kind of dementia to be dementia since the difference between normal dementia and schizophrenic dementia is quite large. Let’s take a brief look at both sides of the issue.


Dementia in schizophrenia: figures

Researchers conducted a hindsight study analyzing previously accumulated data related to dementia and schizophrenia. Researchers tried to find out whether mental illness increases the risk of developing dementia.

The analysis included patients without psychopathology and serious psychiatric pathologies – schizophrenia, bipolar disorder, and relapsing major depressive disorder.

Dementia is diagnosed more frequently in women. It is because they live longer than men, with the last years of their lives alone.

A total of more than 8 million people over the age of 66 were analyzed, of which 63.4% were women with an average age of 74. More than 74,000 had a schizophrenic diagnosis (57% were women).

The results were as follows:

  • At age 66, 27.9% of schizophrenic patients had dementia, while only 1.3% of healthy patients had dementia.
  • By age 80, the prevalence of dementia among mentally healthy people had risen to 11.3% and among schizophrenic patients to 70.2%.
  • The annual incidence per 1,000 people at age 66 was 52.5 among people with schizophrenia and 4.5 among comparison group subjects.
  • By age 80, the rate had risen to 216.2 (out of 1,000) among schizophrenics and 32.3 among healthy controls.

This study suggests that patients with schizophrenia have a higher risk of developing dementia than initially mentally healthy individuals.



The above data show the dependence of dementia on mental disorders, but the exact mechanism of its development against the background of schizophrenia is unknown. It has been suggested that patients with schizophrenic illnesses are vulnerable to drugs, heart failure, etc. These, in turn, can trigger the process of dementia.

Also, dementia and schizophrenia are similar because both result from brain damage. The third premise has to do with antipsychotic medications that are prescribed for psychiatric disorders. They could hypothetically also be a factor in the development of dementia.

However, these are all just hypotheses that have yet to be proven. Researchers have yet to find a link not just between schizophrenia and dementia but between the diseases that cause it directly. We are talking primarily about vascular dementia and Alzheimer’s disease.


Schizophrenic dementia

Schizophrenia is a mental pathology that affects thinking. There are many types of it, which differ in the number and intensity of symptoms. But most of them hurt cognitive functions. Schizophrenic disorder is not observed in every mental illness, but we cannot say it is rarely diagnosed.

That said, not all scholars agree on including the concept of “dementia” in the context of schizophrenia analysis. The fact is that many mental functions remain intact in the patient, and only some of them, such as memory, perception and speech, are affected. Some doctors call the schizophrenic’s brain a closet full of books, but to which the key is lost.

The pathogenesis of schizophrenic dementia is still unknown, as are the causes of schizophrenia. However, experts highlight several essential aspects that can consider symptoms of this syndrome:

  • Disorientation in time and space. The patient can find himself anywhere without knowing how he got there.
  • Loss of narrow skills. The patient may forget basic things, such as how to use a vacuum cleaner.
  • Strange behaviour, as if the person does not realize his age. He may behave like a small child who doesn’t know how to put on clothes or tie his shoelaces.
  • Speech disorders. Some patients are silent, while others try to reason, but their reasoning is strange, contradictory, and sometimes outright stupid, pseudo-philosophical.

These are just some signs that are not observed in every form of schizophrenia. But there is no variant of schizophrenia that does not affect the brain in one way or another. Memory, perception, or thinking are always affected. All three cognitive functions can be affected, depending on the type of illness and its course.


Clinical features

Schizophrenia is a very unpredictable illness which can escalate at any time for no apparent reason. However, it is still possible to describe an approximate picture of the development of a schizophrenic disorder. In this case, three aspects are essential – perception, thinking and memory.

The affection of the first is characterized by derealization and depersonalization, which negatively affect the intellect. The patient feels that the world is unreal. He loses touch with it and with his inner self. Even replacement of the real personality with an imaginary one is possible. A severe disease course leads to a complete breakdown of the personality.

Thinking in schizophrenic dementia is atactic. It is characterized by pretentiousness, affectation, formalism and symbolism. Often schizophasia is observed when the patient constructs sentences grammatically correct, but in fact, they are nonsense.

It is not uncommon to have a slipped-in conversation, where the person talks about one thing but is often interrupted and cannot finish the thought. Also, the schizophrenic person often inserts words he invented into his speech. In general, his speech is extraordinary and contradictory.

Memory in schizophrenic dementia persists for a long time. The patient can remember many details, including what he has read. But this largely depends on the general symptomatology. In most cases, the person does not lose basic skills. He can even solve mathematical problems or perform other complex thought operations. For this reason, schizophrenic dementia is not always considered dementia itself.



If a schizophrenic disorder develops, must start treatment as early as possible. Otherwise, there is a risk of the gradual disintegration of the personality.

As the primary method of therapy, in this case, medications are suitable. Nootropics are usually prescribed to increase intellectual activity by up to 90%. With the help of antidepressants, depression and other symptoms of schizophrenia are eliminated.

Schizophrenia is a chronic illness. Even after achieving sustained remission, the diagnosis remains lifelong.

In any case, treatment will be complex. Not only schizophrenic dementia is treated, but also the pathology. One of the main areas of therapy is group and individual psychotherapy sessions.



The prognosis is usually disappointing when dementia develops in the background of schizophrenia. The main task is to stop the progression of the underlying pathology. If schizophrenic dementia has already begun, it is difficult to reverse it. If it ever happens, it is rare and for unknown reasons.

The unfavourable outcome is associated with the growth of negative symptoms of schizophrenia when the patient falls into apathy and becomes feckless and autistic. An indifferent attitude to the surrounding world is observed. Catatonia, residual delirium and other complications are possible.

On the whole, the prognosis for life is favourable. However, everything is much more difficult if we discuss the ability to work. The person may have to be declared disabled of the first or second group and receive a pension. Very severe cases require constant observation and care for the patient.