Schizophrenia definition , history , types , epidemiology , symptoms PDF



    In fact, schizophrenia is regarded as the heart island of the psychiatry and the core of its clinical practice while all other psychiatric disorder are regarded to be secondary. It’s a very grave disease because its prevalent more than the other psychiatric disorder and effect young people ( at the reproductive age) with economic complication. The pt. who’s affected by schizophrenia. Continues normally in his life consuming the same services of any other member in the society. In fact the pt. consumes without production (not giving any service or help for the society), in addition the patient causes also severe distress on the members of his family and other relatives or friends.

It had been found that 10% of the hospital beds in Great Britain were occupied by  schizophrenic. Another study was made on the Gross National Product of America, the result of this study was that about 2% of (GNP of America= 400 trillion $) goes to schizophrenic patients.

Notes about schizophrenia:

  • It occurs before the age 0f (45 years) and affects n mainly clever young people
  • The patient has an own inner life dominated by fantastic ideas, delusions, hallucinations… etc an he is usually cut off from his follows and from reality as whole.
  • The disorders develop gradually in the patients leading ultimately to fragmentation of personality.
  • Certain changes in life can precipitate schizophrenia.
  • Schizophrenia occurs in person who are susceptible to be affected (schizoid personality), seclusions, abnormal shyness, hypochondriasis, emotional coolness, etc… but it can occur in normal individuals.
  • The first psychiatrist who used the term ” schizophrenia” was Bleuler in 1912

History of Schizophrenia

         However writing about schizophrenia  began 19th century and the first one who talked about  schizophrenia was Morel 1856 at time which a young, clever, active and brilliant student with deterioration of personality came to him seeking for help (advise) …morel called that condition as ” dementia praecox”

  • Later on, Kalburn used catatonia for the first time
  • After that , Hecker used for the first time the term “hebephrnia”
  • While in 1896, Kraeplin used the term paranoid for the first time.

In fact Kraeplin believed that the condition ” schizophrenia” was organic in nature and occurs due to long term deterioration which leads to the disorder to personality (disintegration of personality). In addition to that, he regarded all types of this condition that had been described by other psychiatrist (catatonia, paranoid, hebephrenia, etc…) as one disease.

Note: Kraeplin described the condition and illustrated it under the name of dementia praecox and he divided psychoses into mania and dementia praecox

  • Then Bleuler came and he was the first who used the term

” schizophrenia”. This psychiatrist confirmed Freud in his believing and regarded the condition as a psychogenic illness… (a loose association and imbalance in psychic function like thinking, talking a decision, etc..)

The fundamental symptoms: (of Bleuler) 4 A’s

  1. association loosening
  2. affective incongruity or blunting
  3. autism: is a brain development disorder that impairs social interaction and communication, and causes restricted and repetitive behavior .
  4. ambivalence simultaneous of conflicting emotional attitudes toward a goal, object or person. While the secondary symptoms are:
  • delusion
  • hallucination
  • After Bleuler the psychiatrist came who was :Schneider” and

illustrated the followings are the rank symptoms that are pathognomic of schizophrenia  in the absence of organic brain disorder:

  • Thought echo: his thoughts are loudly felt by the patient
  • Running commentary: the patient hears one voice commenting continuously on his work and behavior
  • Third person hallucination: two voices are heard by the patient talking with each other about the patient behavior, in this condition the patient considered as the 3rd person
  • Delusions of control (insertion)
  • Delusions of control (withdrawal or deprivation)
  • Delusions of control (broadcasting)
  • Passivity delusions of emotion
  • Passivity delusions of thinking
  • Passivity delusions of action
  • Somatic passivity , his internal sensation are affected by external forces (nerves, stomach, ect…)
  • Delusional perception, the presence of the two memberedness is essential

 Types of schizophrenia

  • Simple schizophrenia : is poverty in activity, thinking, volition, . and this condition is sometimes confused with mental subnormality
  • Hebephrenia :this is seen in younger age group (disorganized schizophrenia)
  • Paranoind schizophrenia : it is seen in older age group and characterized by paranoid delusions
  • Catatonic schizophrenia
  • Residual schizophrenia
  • Undifferentiated schizophrenia : there are neither delusions nor hallucinations and the disease is not diagnosed well


  • The prevalence of schizophrenia is 1/100, the Iraqi people is about 25 million individuals (250.000 of  schizophrenia ) while in America they are 3 million in No.  and in China they are 20 million in  No.

Note:  the prevalence record (old + new) cases

  • The incidence of schizophrenia is 15/100.000 so if we have one million then the incidence is 150 new cases per year.
  • The onset of schizophrenia is usually insidious but may be acute in certain occasions.
  • Male/female ratio is equal but the mail usually affected (4-5) years earlier than female. If females are effected at 30 years of age the males will be at 25 of age.
  • It occurs usually more in low socioeconomic status and in the centre of cities more than the rural areas. It is more prevalent prevalent in emigrants.
  • The winter born infants are more liable (susceptible) to be affected by schizophrenia than others, but this relation ship between seasonal birth and the disease is not necessarily true, it may be due to hidden factors such as
  • Influenza
  • Poor diet
  • Viral infection
  • Birth trauma
  • Others
  • Schizophrenia are with low fertility


Before the demonstration of diagnostic of schizophrenia, there are certain notes that must be put in mind:

  • Understimulation :increases the negative symptoms such as poverty of speech, apathy, catatonia, etc….

While overstimulation induces positive symptoms such as hallucinations, delusions, restlessness, etc..

  • High expressed emotional families are considered as an

overstimulant leading to relapse and this is the cause that makes those persons prefer a hostel rather than their home

  • The prevalence of schizophrenia is higher than the incidence because some of the patients become chronic cases
  • Multifactorial inheritance is responsible for schizophrenia . This means that the disorder is or may be transmitted to children through the genetic material but needs certain environmental factors to be expressed.

It does not always appear especially when the environmental factors has been provided during the life of the person

  • Schneider rank symptoms :

The first rank symptoms are :

Thought echo, running commentary, 3rd person hallucination, disorders of possession ( insertion, withdrawal, broadcasting), passivity delusions of emotion, thinking and action, somatic passivity, delusion perception.

The second rank symptoms are: paranoid delusions, auditory hallucinations in the form of noises, 2nd person (here the voices talks directly with him rather than commenting on his behavior as in running commentary

  • It has been found that schizophrenia is more common among people born in the winter months. This can be explained by the greater risk of maternal virus infection in autumn and winter, with the probability that such an infection could interfere with the brain development of fetus. It’s not the winter itself responsible for that but the hidden factors.
  • Bleuler considered schizophrenia as a psychogenic disorder and said that the delusions and hallucination are 2ndary symptoms of this disorder but they are the primary and main symptoms of schizophrenia (and this was his mistake) the word “mistake” refer to the symptoms only.
  • While Kraeplin considered schizophrenia to be organic in nature (not psychogenic). So the differ from Freud and Bleuler who did not confirm the “organic nature of schizophrenia. Lastly, Schneider considered the hallucination and delusions as the main symptoms (more accurate)

 The diagnostic criteria of  schizophrenia:

         Depending on the DSM IV

I-characteristic symptom: primary  symptoms:

  • Delusions
  • Hallucinations
  • Disorganized behavior
  • Negative symptoms

Note : two (at least) or more must be found to say that the characteristic symptoms are present , but the presence of either 3rd person on running commentary or bizarre delusions is enough to say that the characteristic symptoms are present [according to Schneider]

II- social and occupational deterioration (dysfunction)

III- The symptoms of the patient must continue for six months or more

Note : If the symptoms last less than 6 months then the disorder may be either brief psychotic disorder (1 day- 1 month) or schizophreniform disorder (1-6 months)

IV- the disturbance is not due to effects of a substance (e.g. drug abuse, medication ) or a general medical condition.

V- relationships to pervasive developmental disorders  like autistic disorders . In which  addition diagnosis of   schizophrenia is made on if prominent hallucination and delusion are present.

The difference diagnosis of  schizophrenia is:Schizophrenia definition , history , types , epidemiology , symptoms

  1. Schizophreniform disorders
  2. Schizoaffective disorders
  3. Delusion disorders
  4. Brief psychotic disorders
  5. Shared psychotic disorders
  6. Substance induced psychoses
  7. Psychoses due to medical conditions
  8. Psychoses not otherwise specified

Etiology  of  schizophrenia:

  The cause of this disorder is unknown until now, but the huge studies that had been made about this subject in the last century led to many theories:

However, it had been found that  schizophrenia has biological basis plus environmental factors “social and psychological causes”  so schizophrenia is ” biopsychosocial in origin” which means that the biological causes are essential and must be present as a basis and the environmental causes either precipitate or maintain the disorder. In fact, life changes like marriage, entrance into college, going into a new house have a profound effect in precipitating the psychotic disorder or maintain it.

  • Biological causes
  • Environmental factors

1-Biological causes:

Hereoittary causes (Genetics):

Three types of studies had been made on schizophrenics to confirm that the disorder has a genetic basis (i. e. that is transmitted from parents to children by genetic factors) and that include:

  • Family studies
  • Twin studies
  • Adopted children studies

So in details:

  • In family studies, it had been found that the :
  • 2nd and 3rd degree relatives have a 2.5% more possibility than the general population to be affected by the disorder (5 in every 200 are affected).
  • In the children of one schizophrenic parent have 12% more possibility.
  • If both parents are schizophrenics, the 25% will be affected of their children (i.e. if the schizophrenic parents have 4 children then one of them will be affected).

It’s not clear if the presence of one schizophrenic patient in the family will affect the other members of the family or relative by a genetic basis or environmental one because the presence of this patient may have an effect on rearing  up of the other members of the family and relatives.

  • Twin studies:

The twins are either identical (the twin have the same genetic material) or non identical (the twins have different genetic material).

In fact, the study of identical twins gives more accurate information about the genetic role towards this disorder.

  • It has been that 45% of the identical twins share in the disorder (if patiens have schizophrena the 45 of their identical twins have also the disease)
  • While only 12% of non identical twins share the disease and in this condition, the two have a weaker link.

So genetics have a role in etiology of the disease, but the environmental factors must be present to complete the final picture of schizophrenia i.e. genetic has no 100% role in etiology

C-adopt children

It had been found that children of  schizophrenia parents (we depend mainly on the mother because the father may be not known) if they are adopted and taken into live in a place which different and far from their parents, they will acquire schizophrenia in their adulthood

The study of adopt children confirms the genetic basis of schizophrenia far away from the environmental factors, but still the environment has its effect in completing the picture.

Conclusion: genetics has its role in etiology of the disorder but its not transmitted from parents to children in mandelian way but its multifactorial

  1. biochemical causes

The etiology of schizophrenia may be rated to the neurotransmission of the brain. It has been found to have a relationship with the disorder. The neurotransmitters that can be found in the brain are numerous like dopamine, ACH, adrenaline, histamine, serotonin, and prostaglandins etc…


  • The vesicles contain neurotransmitters
  • The electrical messages in the brain are actually the thoughts, emotions, … etc. Of ourselves and these electrical messages pass usually across numerous neurons via the synapses
  • The neurotransmitter that is worthy to get our attention is the dopamine which is closely related to the etiology of schizophrenia. This is usually by either its exaggeration effect due to its exces amount or its imbalance with other neurotransmitters.
  • The dopamine neurotransmitter is found in the following places of the brain:
  • Mesolimbic system (between midbrain and limbic system)
  • Mescortical (between midbrain and cortex)
  • Between the hypothalamus and anterior pituitary in which the dopamine is the prolactin inhibitory hormone which is released in the hypothalamus and work on anterior pituitary gland.
  • Between the substantia nigra and the striate body ( the two are located within the basal ganglion) this connection between them is called the nigrostriatal tract (pathway).
  • Social stress (daily life events) causes imbalance or excess of dopamine according to the study that had been made. So the drugs that antagonize the effect of dopamine will reduce the symptoms of  schizophrenia and these drugs are called neuroleptic drugs like chlorpromazine, however the biochemical theory in etiology of  schizophrenia has become weak recently because of :
  1. The appearance of drugs that work on receptors rather than the dopamine receptors with reduction of psychotic symptoms
  2. The drug (dopamine antagonist) works within 1 hour but the effect (therapeutic effect) appears after 2 weeks

3- Birth and pregnancy :

It had been found that winter born babies are more susceptible to be affected by schizophrenia but this may be due to hidden factors as we mentioned previously.

In common (viral infection, dietary factors, birth complication) may lead to schizophrenia in later life (adolescent and adulthood).

Note: a weak study said that atrophic changes in schizophrenia may be due to slowly progressive viral infections

4-Medical illness:

Schizophrenia like symptoms may appear in association with certain medical illnesses like:

  • Carcinoma of lungs.
  • SLE
  • Sarcoidosis
  • Stroke
  • Immune multi systems disease
  • Syphilis
  • Thyrotoxicosis

But the mood of the action by which the symptoms of  schizophrenia are stimulated to appear is unknown.

Note: parkinsonism is not a cause of schizophrenia

5- Organic Brain Disorders:

Radiological investigation like CT scan, MRI have revealed the following (about schizophrenia)

Certain changes (structural and functional) may be associated with the etiology of  schizophrenia which are:

  • Dilation of ventricular systems
  • Atrophy of brain tissue specially the temporal lobe and its medical part which is called the hippocampus
  • Decrease weight of brain becoming less than normal
  • Decrease of blood supply to the frontal lobe leading to frontal hypoplasia
  • Decrease of glucose metabolism in the frontal lobe and disturbing its function.
  • Defect in the functional connection between the different parts of brain (between the lobes).
  • Environmental factors will be discussed in the next lecture