Previously, schizophrenia was categorized into five subtypes: paranoid, catatonic, disorganized, residual, and undifferentiated [1]. In the most recent publication of the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM-5) [2], these five subtypes have been removed, due to concerns relating to the validity and stability of these diagnoses [3].

As such, paranoid schizophrenia is no longer a specific diagnosis, but the symptoms of paranoid schizophrenia and other types of schizophrenia are still used by physicians to form a diagnosis, based on the severity of the presenting symptoms.

What is paranoid schizophrenia?

Schizophrenia can present as a variety of symptoms, including:

  • Positive symptoms: such as hallucinations, delusions, and thought disorders
  • Negative symptoms: such as social withdrawal, loss of motivation, catatonia, and blunted emotions
  • Cognitive symptoms: such as abnormal or disorganized speech and behavior, includingincoherent sentences, difficulty following a train of thought, and odd or repeated movements.

According to the DSM-IV [1], for a diagnosis of paranoid schizophrenia, one or more delusions and/or hallucinations must be present. The person will be very focused on at least one specific delusion, which will typically be persecutory in nature, causing a belief that someone or something will do them harm.

The DSM-IV further states that there must be no persistent negative symptoms, or disorganized speech and behavior for a diagnosis of paranoid schizophrenia. Therefore, paranoid schizophrenia presents solely with positive symptoms.

Symptoms of paranoid schizophrenia

Symptoms of paranoid schizophrenia involve one or more hallucinations and/or delusions.

Although visual and auditory hallucinations are most common, hallucinations can involve any of the five senses [4]:

  • Visual hallucinations: seeing things that are not there, such as people, lights, and shapes
  • Auditory hallucinations: hearing things, such as voices talking to you or about you, or an ongoing commentary of your actions
  • Olfactory hallucinations: smelling things that are not there
  • Tactile hallucinations: feeling things that are not there, such as bugs on your skin or someone touching you
  • Gustatory hallucinations: tasting things that are not there

Delusions involve having a strong belief in something with no evidence, or that is clearly incorrect. Examples of delusions may include [4]:

  • Perception: a normal occurrence is given an abnormal meaning, for example, a bird flies overhead and this means that an alien spaceship is going to land, or a song comes on the radio and that means the radio is communicating a special message to you.
  • Idea: a current belief, such as the idea that the CIA are listening to your phone calls, or that someone is trying to kill you.
  • Thoughts: thought insertion, broadcast, or withdrawal, which means that you feel you are not in control of your thoughts in some way. You may believe that other people can hear your thoughts, put thoughts into your head, or take them out.

Often within paranoid schizophrenia, these hallucinations and delusions will be persecutory in nature, meaning that the person will believe someone, or something, is trying to harm them in some way. Because of this consistent fear of persecution, symptoms of paranoid schizophrenia can also include [5][6]:

  • Social withdrawal
  • Inability to trust others or form friendships
  • Anger, hostility, or aggression
  • Hearing voices telling you to harm others
  • Hearing voices that make derogatory or nasty remarks about you
  • Believing that people are trying to poison you, that people are following you, or that your home or phone are being watched or listened to
  • Difficulty concentrating or focusing
  • Using illicit substances
  • Suicidal thoughts
  • Treatment noncompliance, such as forgetting or choosing not to take medication, or declining to attend appointments with professionals
  • Poor level of self-care

Causes of paranoid schizophrenia

Brain structure and function

Research suggests that schizophrenia may be caused by changes in neurotransmitter levels, particularly dopamine and glutamate [7].

There is also evidence to suggest that people with schizophrenia have differences in their brain structure, including a decreased amount of gray matter, suggesting that it could be caused by impaired development of the brain [8].

Similarly, traumatic brain injury could cause an onset of psychosis or schizophrenia, also suggesting that brain structure can contribute to the development of the condition [9].


Schizophrenia is more common in those with a parent or close relative with the condition, than in those without. However, a family history of schizophrenia does not definitely mean that the condition will develop in offspring [7].

Social and environmental influences

Schizophrenia may be triggered by various social or environmental factors, such as stress, childhood trauma and abuse, social isolation, socioeconomic class, and complications during pregnancy and childbirth. These factors have been found, alone or in combination with others, to increase the risk of psychosis and schizophrenia [10][11].

Alcohol and drugs

Substance use, in particular the use of cannabis, has been found to increase the risk of psychosis. This risk is higher in those who use cannabis from a younger age, in large doses, and of a high frequency and regularity [11][12].

Similarly, some research suggests that cocaine, amphetamines, and alcohol can contribute to an increased risk of psychosis [11].

Treatment of paranoid schizophrenia


Antipsychotic medication is typically used in the treatment of all types of schizophrenia and can help alleviate most symptoms. Your doctor will initially prescribe a second-generation antipsychotic medication, such as olanzapine, aripiprazole, or risperidone.

People respond to medications differently, so what works for one person may not work for another. You may need to try more than one medication, or a combination of medications, before you find an effective treatment.

If you have had limited success with two or more antipsychotic medications, you might be prescribed clozapine. It is a very effective medication for the treatment of schizophrenia, but it can have severe side effects and risks.  This is why it is not a first choice of medication, and it requires careful monitoring, including regular blood tests [8].

Many antipsychotic medications can cause side effects of varying severity, which is one of the reasons that some people don’t take their medication regularly. Also, people with schizophrenia sometimes lack insight, meaning that they do not think they are unwell, so don’t think they require medication. Medication noncompliance can cause a relapse of symptoms [6].

It is important that you take your medication exactly as prescribed, as taking too much, missing doses, or suddenly stopping your medication can cause adverse effects and can worsen your condition.


There are various types of therapy that can be useful for the treatment of schizophrenia. However, people who experience paranoia may be reluctant to attend therapy, so this may not be an appropriate treatment for all.

Cognitive behavioral therapy (CBT) can be helpful for adapting negative thoughts and behaviors, gaining insight about your condition, and preventing relapse [8].

Family therapy can be useful for some people, as it can help the family to better understand and manage their loved one’s condition, symptoms, and behavior [13].

Psychosocial treatments can help you to learn social skills, manage your condition, understand the importance of your medication, and find support in others who have coped with similar experiences [7].


  • Avoid drugs and alcohol: Drugs and alcohol can have detrimental effects on your mental health, potentially causing a relapse. They may also interact with your medication, which could cause serious side effects and risks to your physical health [10].
  • Attend all appointments: Ensure you attend all arranged appointments with your doctor, mental health nurse, and anyone else involved in your treatment, so that you continue to receive the proper care and treatment that is required for your recovery, and to ensure that they are aware of any changes or improvements in your mental and physical health.
  • Get enough sleep: Sleep is very important in improving or maintaining good physical and mental health, and a lack of sleep can contribute to a worsening of your symptoms. Try to develop a good routine for bedtime and get around 8 hours each night.
  • Be active: Do things that you enjoy, as this can help prevent symptoms from worsening. Helpful activities include exercise, meditation, walking, reading, games, and spending time with friends.

Other types of schizophrenia

Schizophrenia is no longer diagnosed as one of five specific subtypes, but the symptoms of each subtype are still used in formulating diagnoses. Along with paranoid schizophrenia, the other four previously used subtypes of schizophrenia were [1]:

Catatonic schizophrenia

Catatonic schizophrenia involves abnormal psychomotor function. This can be an inability to move, excessive or hyperactive moments, or odd and unusual movements or postures [1].

A common symptom of catatonic schizophrenia is immobility, or stupor, which means that the person appears frozen in place, sometimes for hours or days, and can be in odd positions for long periods of time.

Other common symptoms are echolalia and echopraxia, which respectively mean mimicking other people’s words or mimicking other people’s actions [14].

Disorganized schizophrenia

For a diagnosis of disorganized schizophrenia, hallucinations and delusions may be present, but the primary symptoms would be disorganized speech and behavior [1]. This could include saying bizarre things, quickly changing topics during conversation, repetition of words and phrases, or feeling often confused about things.

Another common symptom of disorganized schizophrenia is flat affect, meaning that the person will be expressionless and show inappropriate, or unusual responses.

Residual schizophrenia

People with a diagnosis of residual schizophrenia would have no prominent examples of positive symptoms, such as hallucinations, delusions, and disorganized speech, but there would be a clear disturbance in their cognition. They may experience negative symptoms and odd beliefs.

Undifferentiated schizophrenia

Undifferentiated schizophrenia was diagnosed when symptoms of schizophrenia were present, but the criteria for any of the other subtypes was not clearly met.


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  6. Krzystanek, M., Krysta, K., & Skałacka, K. (2017). Treatment compliance in the long-term paranoid schizophrenia telemedicine study. Journal of Technology in Behavioral Science, 2, 84–87.
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  12. Marconi, A., Di Forti, M., Lewis, C.M., Murray, R.M., & Vassos, E. (2016). Meta-analysis of the association between the level of cannabis use and risk of psychosis. Schizophrenia Bulletin, 42(5), 1262–1269.
  13. Patel, K.R., Cherian, J., Gohil, K., & Atkinson, D. (2014). Schizophrenia: overview and treatment options. P & T: A Peer-Reviewed Journal for Formulary Management, 39(9), 638–645. Retrieved from
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