Schizophrenia Age Onset: When Is It Most Common For People To Develop Schizophrenia?

Reviewed by Whitney White, MS CMHC, NCC., LPC

Published 10/12/2022

What Is Schizophrenia?

Schizophrenia is a chronic mental disorder with a challenging diagnosis process. It is a life-long mental illness that mainly affects a person’s thoughts, perception of reality and social and emotional activities. The most famous symptom of schizophrenia presented in popular culture are audio-visual hallucinations, however it is important to note that you can have schizophrenia without suffering from hallucinations. According to WHO (the world health organization), about 20 million people worldwide are affected by this brain disorder. The main cause of schizophrenia is still unknown with several genetic and environmental factors playing a role in its development. Persistent treatment can help in subsiding most of the symptoms and the patient can lead a fulfilling work life and personal life.

Schizophrenia is a condition that can be very stressful for the affected individuals as well as their families and friends. If you are an individual who suspects he or she has schizophrenia, or you are worried that a friend or family member may be suffering, here is a simple schizophrenia test to give yourself an idea whether you or a loved one requires further medical or psychiatric help. While this online test can be very informative and helpful, it is important to note that it cannot act as a substitute for an official diagnosis from a mental health professional. For any information regarding treatment or medical care, remember to seek a licensed mental health care providers’ advice.

What Are the Signs and Symptoms of Schizophrenia?

The symptoms of schizophrenia are categorized into three types: Positive, negative and cognitive symptoms. These signs and symptoms are the main focus of psychiatrists for schizophrenia diagnosis.

Positive Symptoms are usually the symptoms that are noticeable and turn out to be the center of the treatment. These may include:

  • Hallucinations: These include hearing voices and/or seeing things that are not real. The person may not be able to differentiate between real and unreal experiences. It is unclear what determines what a person’s hallucinations may be.
  • Delusions: These include having false beliefs that are not based on reality such as, having superpowers, while they may not include audio-visual hallucinations, an individual may believe that they have found signs in radio shows, songs, or numbers.
  • Confused Thinking: The thought process is disrupted and intermingled with several different thoughts. This also affects the ability to communicate as jumbled thoughts result in jumbled speech and often the individuals place unrelated sentences together. For this reason, it may be difficult to communicate with a symptomatic schizophrenic person.

Negative Symptoms: These are the symptoms that refer to the loss of normal functions. These symptoms can be observed very early in the disease, but they are most prominent after the positive symptoms have subsided due to treatment. These may include:

  • Lack of motivation and interest in everyday life
  • Reduced emotional expressions and speaking
  • Social withdrawal and inability to feel pleasure.

Cognitive Symptoms: These are psychological symptoms that may affect a person’s intellectual capabilities. These may include:

  • Difficulty in keeping up with conversations
  • Problems with memory and focus
  • Trouble processing new information

When Is Schizophrenia Diagnosed?

Research suggests that the onset of symptoms in schizophrenia is usually in late teenage to mid 20’s. The occurrence of schizophrenia in children is very rare. Even early onset of schizophrenia occurs before or near age 18 while diagnosis of schizophrenia before age 13 is extremely uncommon. However, there are chances that the symptoms of schizophrenia remain unnoticed and are therefore not diagnosed until two or three years after the onset of the disorder.

For men, research shows the symptoms of schizophrenia tend to become prominent in late teens to early 20’s while in women the onset of symptoms may be in their 20’s to early 30’s. Cognitive symptoms might be present earlier, such as unstable relationships with family, friends or/and co-workers, inadequate performance at school or work, reduced interest and lack of motivation in everyday life. For a person to be diagnosed with schizophrenia, the symptoms should initially develop in early 20’s and should continue for a period of at least six months.

What Are the Criteria For A Schizophrenia Diagnosis?

Psychiatrists and mental health professionals around the world follow the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) and/or the International Classification of Diseases (ICD-10) for schizophrenia diagnoses. Both the DSM and the ICD provide guidance for the proper diagnosis and treatment of several mental diseases.

Diagnostic and Statistical Manual of Mental Disorders (DSM-5):

The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) was put together by the American Psychiatric Association and it is suggested as a standard reference guideline for mental disease diagnosis. The sole focus of DSM-5 is on mental disorders and how they can be diagnosed. The clinical symptoms stated as guidelines for schizophrenia diagnostic criteria are as follows:

At least two of the following symptoms should be present for one month, maximum.

  • Delusions
  • Hallucinations
  • Disorganized Speech
  • Negative symptoms (social withdrawal, reduced emotional response)
  • Cognitive symptoms (social and emotional withdrawal).

Also, any of the signs of schizophrenia should persist for six months for a well-founded schizophrenia diagnosis.

International Classification of Diseases (ICD-10):

It was formulated by WHO and set as a standard for diagnostic purposes. It encompasses the diagnosis and treatment of all types of diseases whether related to the brain or any other body part. The schizophrenia diagnostic criteria according to this manual is:

“At least one positive symptom (Hallucinations, paranoia, delusions etc.) or at least two of the negative symptoms (social and emotional withdrawal, lack of motivation etc.) and cognitive symptoms (memory lapse, trouble focusing etc.) should be actively present for at least one month.”

How Do You Test for Schizophrenia?

To test and receive a proper diagnosis for schizophrenia, it’s important to consult a licensed mental health or medical professional. Although many advances have been made in the field of schizophrenia diagnostics, there are no definite schizophrenia tests to make a diagnosis on. However, there are other laboratory tests a doctor might conduct to analyze your symptoms and rule out other possibilities. Following tests might be ordered by a doctor if he/she suspects schizophrenia:

  • A urine or blood analysis to rule out the possibility of alcohol and/or any substance abuse such as methamphetamine (meth) or Lysergic acid diethylamide (LSD).
  • Brain and body scans such as, MRI (magnetic resonance imaging) and CT (computerized tomography) scans to rule out any possible tumors.
  • Cognitive tests such as personality tests, memory tests, mental status examinations, and detailed evaluative interviews, assess a person’s mental and intellectual capacities and rule out the possibility of any other brain disorder.

How Does A Doctor Diagnose Schizophrenia?

After the preliminary laboratory tests, if the medical doctor does not discover any physical cause of the symptoms (delusions, hallucinations, disorganized thought/ speech). They might then refer the person to a mental health professional for a thorough assessment of the signs and symptoms to be associated with schizophrenia.

A mental health professional like a therapist, psychologist, or psychiatrist might conduct several interviews and utilize specifically designed cognitive tests to assess the mental symptoms for a schizophrenia diagnosis. The diagnosis is mainly based on the personal history and observations of a person’s demeanor, performance at work/school personal beliefs, thoughts, moods and attitude towards family and friends.

The professional may then conform the criteria mentioned in DSM-5 for schizophrenia diagnosis by six-month persistence period of the tell-tale signs of schizophrenia.

How Do You Treat Schizophrenia?

At present, schizophrenia is a life-long condition with no cure. The most important aspects of navigating schizophrenia to have a full and fulfilling life are having a stable support group and the right type of treatment.

It is also important to note that just as schizophrenia varies from person to person, so will the treatment plans. When it comes to mental health, there is no “one size fits all,” which, again, makes it imperative that a professional assess your situation and design a plan that works for your specific needs. For all guidance regarding treatment, please consult a licensed mental health professional.


Schizophrenia can only be diagnosed by a licensed mental health or medical professional. However, there are resources like online schizophrenia symptomscreening that can offer some insight into the common symptoms typically associated with schizophrenia. Remember that these tests are not a replacement for an official diagnosis but can shed some light on some of the symptoms you or a loved one may be experiencing.

It is important to note that schizophrenia can be quite similar to other mental health disorders. That is why the diagnosis process will often start with ruling out other possibilities for delusions or schizophrenia symptoms.