Etiology of schizophrenia:
The cause of this disorder is un known until now but huge study that have been made about this subject in the last century led to many theories.However it had been found that this disorder has biological and environmental factors (social and psychological causes) so schizophrenia is biopsychosocial in origin.
This means that the biological causes are essential and must be present as basis and the environmental causes either precipitate or maintain the disorder. In fact life changes like marriage ,entrance into college, going to new house ,have a profound effect in precipitating the psychotic disorder or maintain it .
I-Biological causes:
Hereditary, biological, birth& pregnancy,medical disease,organicFirst: Hereditary causes (genetics)
Three types of study had made on schizophrenia to confirm that the disorder has genetic basis.
1-family study 2nd 3rd degree relatives 2-5%
2-twin study (identical 45%-non identical 12%)
3-adopted children studies.
In family studies, it had been found that 2nd and 3rd degree relatives have 2.5% more possibility than the general population to be affected by this disorder(5 in every 200 are affected). While the children of one schizophrenic parents have 12% more possibility and if both parents affected; then 25% of their children will be affected {if the parents are schizophrenic and have 4 children so one is affected}.
It is not clear if the presence of one schizophrenic patient in the family will affect the other members or relatives by genetic base or environmental one because the presence of this patient in the family may have an effect on rearing up the another member of family or relatives.
Twin studies:
Identical and non-identical; in fact the study of identical twins gave more accurate information about the genetic role toward this disorder.
It had been found that 45% of identical twins share the disorder that is to say if 100 patient have schizophrenia then 45 of their identical twin will also have the disease.
While 12%of non-identical share the disease and in this condition the two have weaker link.
Note /genetics has a role in the etiology of the disease but the environmental causes must be present to complete the final picture of it (genetics does not have 100% role in it).
Adopted children
It has been found that the children of schizophrenic parents (we depend mainly on mother because the father of child may not known) if they are adopted and taken to live in a place which is different and far away from that of their parents they will acquire schizophrenia in their adulthood.
The study of adopted children confirm the genetic basis of the disorder far away from the environment factors but still the environment has its effect on completing the pictures.
Conclusion: genetics has its role in etiology of the disorder but not transmitted to children in Mendelian way but it is multifactorial.
Second: biochemical causes
The etiology may be related to neurotransmitters of the brain. It has been found to have a relationship with the disorder. The neurotransmitters that can be found in brain are (dopamine-acetylcholine-adrenalin-histamine-serotonin-prostaglandins…etc).
1- the vesicles contain neurotransmitters
2-the electrical messages in brain are actually thoughts, emotions, of ourselves and these messages pass through neurons by synapses.
3-the neurotransmitter dopamine is closely related to the etiology of schizophrenia by either its exaggerating effect due to excess amount or its imbalance in relation to other neurotransmitters.
4-the dopamine found in following places:
-mesolimbic system between midbrain and limbic system responsible for schizophrenia
-mesocortical between midbrain and cortex
-between hypothalamus and anterior pituitary in which dopamine is the prolactin inhibitory hormone which is released in the hypothalamus and works on anterior pituitary gland.
-between the substania nigra and stria body within the basal ganglia which responsible for Parkinsonism
5-social stress causes imbalance or excess of dopamine according to a study had made.
*so the drugs that antagonize the effect of dopamine will reduce the symptom of schizophrenia(neuroleptic drugs e.g. Chlorpromazine).
However the biomechanical theory in etiology of schizophrenia has become weak recently because:
a-The appearance of drugs which act on receptors rather than dopamine receptor which reduce the psychotic symptoms.
b-These drugs (dopamine antagonists) work within one hour but the therapeutic effect appears after two weeks.
Third: birth and pregnancy
It had been found that winter borne babies are more susceptible to be affected by schizophrenia but this may be due to hidden factors. In common (viral infections, diet, birth complication)may lead to schizophrenia in later life (adolescence, adulthood,)
Note/a weak study said that atrophic changes in schizophrenia may be due to slowly progressive viral infection.
Fourth: Medical illnesses
Schizophrenia like symptoms may occur with association with certain medical illnesses like:
-Carcinoma of lung
-SLE
-sarcoidosis
-stroke
-immune multisystem disease
But the mode of action by which the symptoms of schizophrenia are stimulated to appear is unknown.
Five organic brain disorder
Radiological investigation by CT, MRI have revealed the following; certain changes like structural and functional may be associated with etiology of schizophrenia:
1-dilation of the ventricular system
2-atrophy of brain tissue especially temporal lobe and its medial part (hippocampus)
3-weight decrease of brain becoming less than normal
4-decrease of frontal lobe blood supply leading to frontal lobe hypoplasia
5-decreas glucose metabolism in frontal lobe lead to disrupting its function.
6-defect in the functional connection between different part of brain tissue
II- Environmental factors:-
As mentioned previously, schizophrenia appears to be a complex disturbance occurring at many levels in which biological factors are essential and environmental factors are necessary to precipitate or maintain the disorder .
Any how , the environmental factors can be divided into :
1_Social causes , which divided into
a-Early life event (rearing up)
b-Recent onset.
2-Psychological causes.
1-Social causes:-
A_ Early life events:-
If the father or especially the mother have schizoid traits, there may be considerable effect (directly or indirectly) on their child and his personality.
The following situation can be a good example:-
If the parents punish their child for every large and small mistake(even the trivial one) , then the child may expect punishment whatever he does , more over he may expect punishment if he makes no choice and no action . Here, the child will learn to avoid punishment by doing meaning less remarks and the child begins to become abnormal in behavior and personality.
B _Recent life events:-
It had been found that the disorder (schizophrenia) can be triggered off by a variety of life events such as moving to a new house, loss of the job, illness , operations , accidents , marriage , joining the army, etc…
Note\ These life events precipitate either the onset of the first schizophrenic syndrome or relapse of the disorder on remission (rarely) of schizophrenia.
Scientists who made study about the effects of life events:-
Steinburg & Durral (in America):-
They studied the soldiers after joining the army and found that relapse of schizophrenia occur in the first month after army joining. so life events have an effect in triggering this psychotic disorder.
Brown & Birely (1968):-
They studied the (12 weeks) period before the onset of schizophrenia of 50 patients and found that stressful life events where present in 3 weeks period before the episode (onset of schizophrenia). So life event especially recent onset has their effect in the etiology of the disorder.
Brown (1972):-
He studied the causes of relapse of schizophrenia in recent cases by observation of the patients after remission from the acute face for 12 months .
He found that relapse rate was high in families making critical comments on the patient's behavior (eg. family member who make these comments are the father, the mother, the wife, etc…)
Note\ the families whith excess critical comments are called high expressed emotional families.
He found also that relapse rate decreases by applying the following:-
1- Drug therapy
2-The contact of the patient with the critical relative must not exceed 35 hours per week (5 hours daily).
The relapse rate according to Brown's study was 58% in high expressed emotional families and only 16% in families who do not comment on patient's behavior. He found also that relapse rate decrease more by antipsychotic drugs.
Beblinton:-
This scientist studied high number of schizophrenics (1250 cases) and found that relapse rate was 50% in high expressed emotional families and only 21% in low expressed emotional families.
2_Psychological causes:-
There are theories to explain the psychology of the schizophrenic patients:-
Filter theory of sensory input or overload:-
In ordinary state, we perceive only the wanted information and neglect the unwanted information.
But the schizophrenic patient is opened to all events of environment and react with the events and conversations he sees and hears in a manner as to be related to him.
Frith theory :-
The negative symptoms of the schizophrenic patient is due to inability of having spontaneous action (will) and some of the positive symptoms like hallucination are due to the inability of the patient to take intention of voluntary action (passivity delusion of action , emotion , thinking( .
He also does not know the intention of other people acts and think that these acts are done to hurt him (against him), but actually these acts are carried out by others in no relationship with the patient, so the paranoid delusion develop.
Summary:-
It had been found from the genetic, neuropathological, and epidemiological finding that schizophrenia is a neurodevelopmental disorder.
The architecture of temporal lobe and hippocampus are abnormal and the connections (as a whole or especially with temporal lobe) are also abnormal.
The developmental disorders are either due to genetic factors (genetically determined) or due to injury of developing brain intrauterine (at the time of pregnancy) or at the birth.
This explain enlargement of the ventricular system , and other changes like abnormal behavior during childhood.
The question is ((why does it appear in adulthood?))
Answer is: this is due to maturation changes (demyelination of neurons, modification of synaptic regions) until adulthood .
Ex: if a small monkey is traumatized in the frontal lobe , the symptoms appear only at adulthood but not immediately.
So the social, psychological factors , etc… precipitate the illness by the presence of a biological basis.
Note \ At one day , we may be able to prevent or treat the disorder accurately by knowing the exact etiology of it.
The course of schizophrenia:-
Most of patients have a relapsing remission course and full recovery is rare after the first episode.
Other patients may enter the chronic phase and about (80_90)% of patients previously enter the chronic phase due to delay diagnosis , absence of effective treatment (drugs and psychotherapy ). But nowadays, the picture is different … only (5_10)% enter the chronic phase because of early diagnosis and successful treatment which prevent the chronicity to be established.
Prognosis:-
Previously, most of schizophrenic patients were hebephrenic in type (bad sign) but now a day, most of them are paranoid schizophrenics (better sign) because their personality is better developed.
Good prognosis is suspected when the following signs are present:-
1_Delayed onset .
2_ Acute illness.
3_Marriage.
4_No schizoid personality.
5_The patient completed his academic study before disorder onset.
6_Early diagnosis and treatment.
Bad prognosis is suspected when the followings are present:-
1_Early onset .2_Insedious (with prodromal period).
3_No marriage.
4_Schizoid personality.
5_The patient didn't complete his academic study.
6_Late diagnosis and treatment.
7_Simple schizophrenia
8-Hebephrenic schizophrenia is worse prognosis than paranoid schizophrenia.
Treatment of schizophrenia :-
In acute cases, admission to the hospital is necessary followed by taking thorough history and then assessment is done for need of any particular type of treatment.1_Physical treatment:-
A _ Drugs.
B _ Electroconvulsive therapy.
2_Psychotherapy.
3_Social support.
The drugs are called (neuroleptics or antipsychotic or antischizophrenic drugs) and they act to control dopamine excess (typical drugs) or by another mechanism (atypical drugs).
The typical drugs:-
A-Phenothiazine group :
1_ Chlorpromazine.
2_ Thioridazine.
3_ Trifluoperazine.
4_ Eluphenazine.
B-Butyrophenone group:
Haloperidole.The most commonly used drug is chlorpromazine with a dose of 3oo mg\day (could be 600mg\day but not more than 900mg\day) with a sedative effect at the beginning and the therapeutic effect after two weeks.
The dose may be increase or decrease accordingly.
The treatment is usually for (6_8) weeks after which the schizophrenic symptoms disappear. After that, maintenance drug therapy is continued with the patient (to at least 1 year)
Note\ we can shift to another drug when the patient become good and quite which is the fluperazine (5mg (3 times)\daily) but without a sedative effect.
Important Notes:
The first rank symptoms of Schneider concerning the psychiatric disorder (schizophrenia) are :-
1_Voice repeating the person's thought aloud (thought echo).
2_Running commentary on the person's action .
3_Third person.
4_Delusion concerning the possession of thought (insertion).
5_Delusion concerning the possession of thought (withdrawal or deprivation).
6_Delusion concerning the possession of thought (broad casting).
7-Delusion perception (primary delusion).
8_Somatic passivity.
9_Primary delusion (sudden delusion ideas coming without preceding events …eg.. hallucination etc…)
10_Outside agencies causing the person's feeling (emotion).
11_Outside agencies causing the person's action (acts).
The prognostic sign
What are the good prognostic sign?
1_Acute onset (not insidious).
2_The prescence of stressful life events leading to the onset of symptoms.
3_Delayed onset.
4_ The patientis married (before appearance of the illness).
5_The patient has complete his academic study before appearing of the disorder.
6_No schizoid personality (normal premorbid personality).
7_No family history of schizophrenia.
8_A family history of depression.
9_Marked affective disturbance.
10_Confusion.
11_Early diagnosis and treatment.
12_Paranoid schizophrenic patients have a better developed personality than hebephrenic schizophrenic patients.
13_Average or above average intelligence.
14_Others.
What are the bad prognostic signs?
1_Early onset (not delayed)
2_Insidious onset (not sudden)
3_The patient is not married.
4_No present of stressful life events.
5_Schizoid personality (abnormal premorbid personality).
6_The patient didn't complete his academic study.
7_Late diagnosis and treatment.
8_Subnormal intelligence.
9_Prescence of flattening of symptoms.
10_Enlarge ventricles on (CT\MRI) scanning.
11_Poor insight.
12_High expressed emotional families.
13_Long episode.
14_Prescence of negative symptoms.
15_Hebephrenic &simple schizophrenia are of worse prognosis than paranoid.
16_Family history of schizophrenia.