Schizophrenia: What are the Causes, Symptoms and Diagnosis

Schizophrenia: What are the Causes, Symptoms and Diagnosis


Schizophrenia definition:

Schizophrenia is a serious mental disorder that affects the patient deteriorating their abilities in various psychological aspects, such as thought, perception, emotions, or will.

It is a mental disorder characterized by the existence of loss of contact with reality (psychosis), hallucinations (usually consisting of hearing voices), false beliefs firmly held (delusions), alterations of thought and behavior, reduction in emotional expression, decreased motivation, deterioration of mental function (cognition) and problems to cope with daily life, including the deterioration of work, social relationships, and self-care.


Schizophrenia is a major global public health problem. The disorder usually affects young people at the age at which they begin to be independent and can produce disability and social stigma for life. In terms of personal and economic costs, schizophrenia is among the worst disorders that affect humanity.

Schizophrenia is a major cause of disability worldwide. It affects about 1% of the population, equally men than women. In the United States, schizophrenia involves approximately 1 in 5 days of sick leave and 2.5% of all health care expenses. Schizophrenia is more common than Alzheimer’s disease and then multiple sclerosis.

It is often difficult to determine when schizophrenia starts, as poor awareness of the symptoms can delay medical care for years. The average age of onset of the disease is between the beginning and the middle of the decade of twenty years in males, and somewhat later in women. The onset during childhood is rare. However, schizophrenia can begin during adolescence or at the end of life.

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The deterioration of social functioning can lead to drug addiction, indigence, and the loss of a reference home. The schizophrenic people without treatment can lose contact with their family and friends, and often they end up living in the streets of big cities.

Causes of Schizophrenia

The exact causes of schizophrenic disorder are unknown, although current research suggests a combination of hereditary and environmental factors. However, it is fundamentally a biological problem (involving brain alterations), not a result of poor parental care or an unhealthy environment in terms of mental health.

Schizophrenia annual rate of change in England

Schizophrenia annual rate of change in England

Among the factors that determine that some people have a greater predisposition to develop schizophrenia include the following:

Genetic predisposition

Previous, subsequent, or concurrent problems at the time of delivery, such as maternal infection with influenza virus during the second trimester of pregnancy, lack of oxygen during delivery, low birth weight, and incompatibility of blood group between mother and child son.

Brain infections

People who have a parent or sibling with schizophrenia have a risk close to 10% of developing this disorder, compared to a 1% risk in the general population. In identical twins, the risk of one developing the schizophrenic disorder is approximately 50% if the other person suffers. These statistics suggest the involvement of hereditary factors.

Symptoms of Schizophrenia

The schizophrenic disorder can appear suddenly, in the course of days or weeks or, on the contrary, gradually, developing over a period of years. Although the severity and characteristics of the symptoms vary among different people suffering from schizophrenia, the symptoms are usually severe enough to interfere with work capacity, social interactions, and self-care.

However, the symptoms are sometimes mild at the beginning (the so-called prodrome). People may simply appear withdrawn, disorganized or suspicious. Doctors can identify these symptoms as the onset of schizophrenia, but sometimes they recognize them only retrospectively.

Schizophrenia is characterized by psychotic symptoms, including delusions, hallucinations, disorganized thinking and language, and strange and inappropriate behavior. Psychotic symptoms include a loss of contact with reality.

Healthy brain and schizophrenia brain

Healthy brain and schizophrenia brain

In some schizophrenic people, there is a decline in mental (cognitive) function, sometimes from the very beginning of the disease. This cognitive deterioration leads to problems in attention capacity, abstract thinking, and problem-solving. The severity of cognitive impairment largely determines the overall disability of schizophrenic people. Many people with schizophrenia are unemployed and have little or no contact with family members or other people.

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Symptoms can be triggered or worsened by stressful life events, such as losing a job or ending a romantic relationship. The use of drugs, including marijuana, can also trigger or worsen them.

In general, the symptoms of schizophrenia are grouped into four main categories:

  • Positive symptoms
  • Negative symptoms
  • Disorganization
  • Cognitive impairment

Those affected may have symptoms of any or all of these categories.

Positive symptoms

Positive symptoms involve an excess or distortion of normal functions. They are the following:

  • Deliriums are false beliefs that generally imply a misinterpretation of perceptions or experiences. In addition, people maintain these beliefs despite the evidence, which clearly contradicts them. There are many types of delusions. For example, people with schizophrenia may have delusions of persecution, believing that they are subject to surveillance, persecution, deceit, or torment. They may have delusions of reference and believe that certain passages of books, newspapers, or songs are addressed specifically to them. They may also have delusions of theft or thought insertion, believing that others are able to read their minds that their thoughts can be transmitted to other people, or that external forces impose thoughts or impulses on them. Delusions in schizophrenia can be strange or not. The strange delirious ideas are clearly implausible and do not derive from ordinary life experiences. For example, the person may believe that someone has removed their internal organs without leaving a scar. The non-strange delirious ideas refer to situations that could occur in real life, such as being persecuted or cheated by the spouse or partner.
  • The hallucinations involve hearing, seeing, tasting, or physically notice things that nobody else sees. Auditory hallucinations are by far the most common. People can hear voices within them that make critical and abusive comments about their behavior or that they talk to each other.

Negative symptoms

Negative symptoms involve a decrease or loss of normal functions. They are the following:

  • The reduced expression of emotions (affective dullness) implies a sample of little or no emotion. The face lacks mobility. People have little or no visual contact. They do not use their hands or their heads to give emotional emphasis while talking. The facts that usually produce laughter or tears do not provoke in them any response.
  • The poverty of speech refers to the existence of a decrease in the productivity of language. The answers to the questions can be laconic, of one or two words, giving the impression of reflecting an interior emptiness.
  • Anhedonia refers to a diminished ability to experience a pleasure. People show little interest in their previous activities and use time in others that lack purpose or purpose.
  • The lack of sociability is the lack of interest in relating to others.

These negative symptoms are often associated with a general loss of motivation, objectives, and sense of purpose.


  • Disorganization implies the existence of extravagant thinking and behavior disorders.
  • The thought disorder refers to disorganized thinking, manifested through language or inconsistency constant changes from one topic to another. The language can be slightly disorganized or totally incoherent and incomprehensible.
  • The extravagant behavior may take the form of nonsense, agitation or appearance, hygiene, or inappropriate behavior. A catatonia is an extreme form of extravagant behavior in which the person maintains a rigid posture and resists the force exerted by others to be moved or, on the contrary, moves suddenly in a random manner.

Cognitive impairment

Cognitive impairment refers to the difficulty of concentrating, remembering, organizing, planning, and solving problems. Some people are unable to concentrate enough to read, follow the thread of a movie or a television show, or follow instructions. Others are unable to ignore distractions or remain focused on a task. Therefore, tasks that involve attention to detail, the development of complicated procedures, and decision-making may be impossible to carry out.


Approximately 5% to 6% of people with schizophrenia commit suicide, about 20% try it and many more have significant thoughts of suicide. Suicide is the leading cause of premature death among schizophrenic peoples and is one of the main reasons why this disorder reduces the average life in 10 years.

Common metal disorders Suicide

Approximately 5% to 6% of people with schizophrenia commit suicide

The risk of suicide is higher in young men with schizophrenia, especially in the case of substance abuse. The risk is also higher when the person has depressive symptoms or feelings of hopelessness, is unemployed or has just suffered a psychotic episode, or has been discharged from the hospital.


The risk of suicide is higher in people who develop schizophrenia in later stages of their lives and who had normal functioning before the onset of the disease. These people retain the ability to suffer pain and anguish, so they are more likely to act in desperation because they are aware of the effects of their disorder. These people are also those who have a better recovery prognosis.

Diagnosis of schizophrenia

Evaluation of a doctor, based on specific criteria

Analysis and diagnostic tests by the image to rule out other disorders

There is no definitive test for the diagnosis of schizophrenia. The doctor establishes the diagnosis based on a comprehensive evaluation of the person’s history and symptoms.

Schizophrenia is diagnosed when the following two conditions are met:

Two or more of the characteristic symptoms (delusions, hallucinations, disorganized discourse, disorganized behavior, and negative symptoms) persist for at least 6 months.

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These symptoms cause a significant deterioration of functioning at work, school, or social relationships.

Information from relatives, friends, or teachers is usually important to establish the date of onset of the disorder.

Laboratory tests are often performed to rule out substance abuse or the existence of an underlying medical, neurological, or hormonal disorder that may have characteristics that coincide with those of psychosis. Examples of these disorders are brain tumors, temporal lobe epilepsy, thyroid disorders, autoimmune diseases, Huntington’s disease, liver disorders, and the side effects of some drugs. In some cases, drug tests are conducted to rule out substance abuse.

Diagnostic tests are performed by the brain image, such as computed tomography (CT) or nuclear magnetic resonance (NMR) to rule out a brain tumor. Although people with schizophrenia have brain alterations that can be visualized on computed tomography (CT) or a nuclear magnetic resonance (NMR), such abnormalities are not specific enough to help establish the diagnosis of schizophrenia.

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