The Ultimate Guide To Schizophrenia: Causes, Symptoms and Treatments

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schizophrenia is a serious mental illness

Schizophrenia is a serious mental illness that affects an individual’s ability to think, to manage emotions and may also affect the behaviour of the person. This is often distressing for both the patient and their loved ones.  Although only 1% of the population worldwide is diagnosed with schizophrenia, the World Health Organization ranked schizophrenia as one of the top 10 disorders leading to the global burden of illness. 


Learn more about the causes, symptoms and possible intervention options for schizophrenia. 


What is schizophrenia?

Schizophrenia is a type of psychotic disorder.  According to the American Psychological Association, schizophrenia is a serious mental illness (SMI) characterized by unclear or irrational thoughts, unusual behavior and speech, and delusions or hallucinations.

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What are the causes of schizophrenia?

Even though the exact causes of schizophrenia are complex and not yet fully understood, scientists believe that schizophrenia can be caused by physical, genetic, social and environmental factors. 


Biological causes of schizophrenia

  • Genetic factors: family risk factors increase the chance of developing schizophrenia. Studies have shown that the risk of developing schizophrenia in someone who has parents or siblings affected is much higher than in someone who has no relatives affected.  
  • Brain structure abnormalities: dysfunction in brain pathways associated with communication increases the chance to develop schizophrenia.  
  • Abnormality in neurochemical activity: research suggests that schizophrenia is caused by high levels of dopamine or high sensitivity towards dopamine in the brain. Based on the association between dopamine levels and the onset of schizophrenia, antipsychotic drugs are often used to treat schizophrenia by reducing dopamine levels.
  • Substance abuse: alcohol or drug abuse are associated with schizophrenia and research argued that the use of substances might increase the biological vulnerability of an individual. People who frequently use ecstasy, methamphetamine, cocaine and cannabis (marijuana) are at higher risk of developing schizophrenia. 

Social causes of schizophrenia

  • Stress and trauma: occurrence of trauma, crisis and stressful life events are often linked to schizophrenia. For instance, a large proportion of schizophrenic patients reported experiencing child abuse in the past. 
  • Prenatal stressors: prenatal stressors increase the chance of developing schizophrenia as pregnancy is a vulnerable period of neurological development. Other conditions caused by prenatal stressors like viral infection, poor nutrition, hypoxia and toxins may also contribute to schizophrenic symptoms.  
  • Environmental stressors: individuals living in poverty or high-crime areas have a higher chance to develop schizophrenia.

What are the symptoms of schizophrenia?

Symptoms of schizophrenia can typically be described as positive and negative. Positive symptoms are additional behaviors that are only displayed in schizophrenic individuals, while negative symptoms refer to an absence of normal mental functions due to schizophrenia. Some common positive symptoms that schizophrenic patients experience are: 



Schizophrenic patients usually suffer from delusions known as fervent beliefs that have no basis in real-life situations. Common delusions include: 

  • Delusions of persecution (e.g. they are going to hurt me) 
  • Delusions of grandeur (e.g. I am destined to save the world)
  • Delusions of jealousy (e.g. my girlfriend is unfaithful to me)
  • Delusions of reference (e.g. everyone is gossiping about me)
  • Surreal beliefs (e.g. I can control your mind)
  • Catastrophic beliefs (e.g. the world is going to end)



Patients with schizophrenia may hallucinate and see, hear or feel sensations that do not exist in reality. There are four types of hallucinations:

  • Auditory hallucination: hearing voices 
  • Visual hallucination: viewing clear or vague images
  • Tactile hallucination: feeling tingling, burning or electric shock sensations
  • Somatic hallucination: experiencing physical sensations


Disorganized thinking and speech

Schizophrenia may reduce cognitive abilities in patients. Common cognitive symptoms include illogical, disconnected thought and speech patterns, thought alienation and derailment. 


On the contrary, schizophrenia can also disrupt normal mental functions and give rise to negative symptoms such as:

  • Lack of emotion
  • Inability to feel pleasure
  • Social withdrawal  
  • Unable to produce meaningful speech
  • Unable to initiate an action

Diagnosis of schizophrenia

Mental health professionals often employ the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) to diagnose patients susceptible to schizophrenia. The DSM-5 has made several modifications for the section named “Schizophrenia and Other Psychotic Disorders” to make the diagnosis more valid and reliable. 


Schizophrenia and DSM-5

According to the DSM-criteria for schizophrenia, individuals who show two of the following symptoms over one month may have schizophrenia:

  • Delusions 
  • Hallucinations
  • Disorganized speech
  • Disorganized behavior 
  • Negative symptoms 

At least one of the symptoms must be delusions, hallucinations or disorganized speech. 

Brain imaging

Since the onset of schizophrenia is sometimes associated with brain structure abnormalities, psychiatrists may order brain scans like magnetic resonance imaging (MRI) and computed tomography (CT) as part of the investigations.


Treatment options for schizophrenia

Biological treatments and psychological treatments are often combined to treat schizophrenia.


Biological treatments

Antipsychotic medications are used in the management of schizophrenia.  There are the older first-generation antipsychotic medications (FGAs) and the newer second-generation antipsychotics (SGAs or atypical).  Nowadays, SGAs are used more commonly as the first-line treatment in schizophrenia because they tend to have a more favorable side effect profile.  Examples of some common side effects include sedation, extrapyramidal side effects such as stiffness of joints, shuffling steps, dry mouth, blurred vision, weight gain, and less commonly tardive dyskinesia which are abnormal writhing movements.


Psychological treatments

Psychological treatments may be helpful as long-term support for patients with schizophrenia. There is good evidence to support the use of cognitive behavioral therapy for psychosis. 

  • Cognitive behavioral therapy (CBT) for psychosis aims to support patients to recognize how their thought patterns might contribute to their feelings and in turn, may affect their vulnerability to illness.

Whilst psychological treatments are generally safe with little to no side effects, most psychological treatments require extensive time and commitment from patients. Patients or their family members must evaluate the targets of each treatment with regard to their specific needs before selecting the intervention approach.

How to help someone who may have schizophrenia?


Educate yourself about schizophrenia

Researching schizophrenia may provide you with a more comprehensive idea about the difficult times your loved one is going through. Avoid joking and applying stereotypes to mental illnesses. 


Joining a support group

Joining a support group formed by relatives of schizophrenia patients may offer you first-hand experiences on how to support your loved one. Meeting others who share similar experiences may also reduce your stress and anxiety when supporting your friend or family member who has schizophrenia.  


Always be there for them

Although patients with schizophrenia may not be able to communicate with you effectively, being there for your loved one can still provide emotional support for them.

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Do you need help?

In case of need for immediate support, please do not hesitate to reach out for professional help. Below is a list of hotlines with 24-hour support.


Program dedicated to help patients with psychosis


Hospital Authority E.A.S.Y. Programme 
Hotline: 29 283 283
Available languages: Cantonese, English 


Suicide prevention hotlines


The Samaritans
Hotline: 2896 0000
Available languages: English, Cantonese, Mandarin


Suicide Prevention 
Hotline: 2382 0000
Available languages: Cantonese 


The Samaritan Befrienders Hong Kong 
Hotline: 2389 2222
Available languages: Cantonese


What might people with schizophrenia experience?

Patients with schizophrenia may see, hear, smell and feel objects or scenes that ordinary people do not experience, i.e. hallucinations.  They may also experience delusions that are untrue beliefs, such as being persecuted by aliens or that they have supernatural powers.

What can trigger schizophrenia?
What should patients with schizophrenia be careful with?

This article was independently written by Healthy Matters and is not sponsored. It is informative only and not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be relied upon for specific medical advice.

Dr. Frances Cheng
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