A chronic and severe mental condition, schizophrenia is a disabling disorder that is characterized of psychotic features such as hallucinations and delusions. While the different types of schizophrenia may have varying signs and symptoms, studies show that all of them probably share the same biological causes.

Signs and Symptoms

A puzzling change in a person’s behavior is one of the first signs of schizophrenia. The person suspected of having schizophrenia may also experience other symptoms which are divided into three categories – positive, negative, and disorganized symptoms.

Positive Symptoms

Positive symptoms include the psychotic features of schizophrenia. These symptoms often render the patient unable to stay or connect with reality. The most common positive symptoms in schizophrenic patients are hallucinations. Hallucinations are changes in a person’s sensation (vision, hearing, smell, or touch) which are not experienced by healthy people. Out of all these senses, hearing voices is the most frequently occurring positive symptom in many schizophrenic patients. These voices may talk to the patient regarding his behavior or warn him of danger. Worse, the voices may order the patient to do things, including suicide or assault.  

Another positive symptom is delusion or false belief. For instance, the person may say, “I am the King of the world!”, which is called a delusion of grandeur. On the other hand, a paranoid delusion is a patient’s belief that someone is attempting to harm him. Specifically, false beliefs about others trying to poison, kill, or spy on them are called delusions of persecution.

Other positive symptoms include disorganized thinking (unable to connect thoughts logically), thought blocking (abruptly stops speaking), neologism (creating meaningless words), and movement disorders such as agitation, repetition or catatonia (the person does not move or respond).

Negative Symptoms

Negative symptoms include those symptoms featuring alterations in normal behaviors and emotions. These include lack of pleasure in daily life, flat affect, inability to begin or continue planned activities, and speaking little or compelled speech.

Disorganized Symptoms

These symptoms include poor ability to make decisions and comprehend information, inability to concentrate or lack of attention, and trouble in using information readily after being able to learn it (working memory).


Each type of schizophrenia has its own unique symptom. Paranoid schizophrenia are extremely anxious, argumentative and often angry. Disorganized ones have their cognitive symptoms more noticeable than the other symptoms of schizophrenia. They are usually childlike and have thinking and expression problems. Catatonic types usually do not move, or are underactive.  Undifferentiated schizophrenia has mixed symptoms of the other types. Residual types may experience some schizophrenic symptoms but not as severe as in full-blown schizophrenia.

Biological Basis

Heredity is one of the most widely known causes of schizophrenia. Studies reveal that schizophrenia emerges in 10% of people having a first-degree relative with this disorder. Identical twins also have 40 to 65% chance of developing schizophrenia if one of them has it. However, the specific gene/s that is associated with schizophrenia has yet to be identified.

Scientists are also conducting studies regarding the effect of neurotransmitters, particularly dopamine and glutamate, in developing schizophrenia. In addition, brain structure may also be a reason for this disorder. For instance, the ventricles of the brain of schizophrenic patients tend to be larger than those of healthy people.


Hospitalization is an essential part of the treatment for schizophrenia due to suicidal ideations and/or inability to perform basic personal hygiene. Antipsychotic medications and psychotherapeutic strategies are all important parts of the treatment process. 

Full reference: 

(Mar 31, 2013). Schizophrenia. Retrieved Jul 24, 2024 from

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