Skip Ribbon Commands
Skip to main content
Navigate Up
Schizophrenia: An Information Guide Centre for Addiction
and Mental Health

What is schizophrenia

Schizophrenia: An Information Guide

On this page:

“I thought space aliens were after me. I didn’t dare leave my room and covered all my windows with aluminum foil to keep them out. I refused to eat because I thought the food was poisoned.”

The young woman quoted above has schizophrenia. She truly believed her delusion. No one could convince her otherwise. Not all people with schizophrenia will have the same type of experience as this woman’s, but they will have some disturbances in thinking, feeling and relating to others.

At least one person in 100 can be expected to develop schizophrenia. Men and women are affected equally; however, men tend to experience their first episode in their late teens or early 20s.With women, the onset is usually a few years later.

How does schizophrenia begin and what is its course?

In most cases, schizophrenia can start so gradually that people experiencing symptoms, and their families, may not be aware of the illness for a long time. In some cases, however, the onset may be more rapid.

Phases of schizophrenia

There are three phases of schizophrenia — prodromal (or beginning), active, and residual. They tend to occur in sequence and appear in cycles throughout the course of the illness.

Prodromal phase

When symptoms develop gradually, people may begin to lose interest in their usual pursuits and to withdraw from friends and family members. They may become easily confused, have trouble concentrating, and feel listless and apathetic, preferring to spend most of their days alone. They may also become intensely preoccupied with religion or philosophy. Family and friends may be upset with this behaviour, believing the person is lazy rather than ill. Occasionally, these symptoms reach a plateau and do not develop further but, in most cases, an active phase of the illness follows. The prodromal period can last weeks or months.

Although the symptoms described above are typical of the prodromal phase of schizophrenia, they may also be due to other causes. If these symptoms are present, they should be discussed with a doctor.

Active phase

During schizophrenia’s active phase, people may experience delusions, hallucinations, marked distortions in thinking and disturbances in behaviour and feelings. This phase most often appears after a prodromal period. On occasion, these symptoms can appear suddenly.

Residual phase

After an active phase, people may be listless, have trouble concentrating and be withdrawn. The symptoms in this phase are similar to those outlined under the prodromal phase. If there have been no symptoms before the first episode, few or no symptoms may be experienced afterward. During a lifetime, people with schizophrenia may become actively ill once or twice, or have many more episodes. Unfortunately, residual symptoms may increase, while ability to function normally may decrease, after each active phase. It is therefore important to try to avoid relapses by following the prescribed treatment. Currently it is difficult to predict at the onset how fully a person will recover.

What are the symptoms of schizophrenia?

“When I first start becoming ill I lose my perspective on the things I hold important, such as courtesy toward my co-workers and roommate.”

“When I’m ill lights are brighter, halls are longer and narrower, walls look like paper and colours are much more vivid. I see faces in the patterns of the rug which begin to have special meaning for me. If I’m lucky and my medication is increased, the symptoms may end here.”

“Sometimes I feel like my arms and legs are disconnected from my body and that my body is disintegrating. I’m terrified to have a bath, because I’m afraid I will disintegrate and float down the drain. Sometimes I’m afraid that I’ll fall apart if I take my clothes off.”

— three first-hand accounts of various symptoms experienced by people with schizophrenia.

The symptoms of schizophrenia fall into two categories — “positive” and “negative” symptoms. The positive, or psychotic, symptoms most often associated with schizophrenia include delusions, hallucinations and grossly disorganized thought, mood and behaviour. Positive symptoms appear during active phases of the disorder. Negative symptoms — deficits in attention, memory, fluency of thought and language, emotional expression, judgment, decision-making and motivation — can be more persistent. These negative symptoms can lead to patterns of social withdrawal and alienation that may disrupt the person’s ability to work and function normally.

People with schizophrenia will likely have one or more of the symptoms mentioned below. However, some of these symptoms are not unique to schizophrenia. It is always necessary to see a doctor for diagnosis.

Positive symptoms

At some phase of the illness, schizophrenia always involves delusions, hallucinations, disturbances in thinking, or disorganized behaviour.


Delusions are fixed, false beliefs that are not consistent with the person’s culture, and have no basis in fact. Delusions may cause people to believe that their bodies or thoughts are being controlled by outside forces, that ordinary events have special meaning for them, that they are especially important or have unusual powers, or that their bodies have changed in some mysterious way. A common delusion experienced by people with schizophrenia is the belief that people are trying to harm them.


Hallucinations are disturbances in perception. If people hear, see, taste, smell or feel something that does not actually exist, they are hallucinating. The most common hallucinations are auditory; that is, people will hear voices talking about them or to them.

Thought disorder is when a person’s thoughts no longer connect in a way that makes it possible to communicate clearly with other people. Thoughts may be jumbled or they may seem to vanish temporarily. When talking, the person may jump from subject to subject and/or may have trouble communicating in a way that is clear and logical.

Disorganized behaviour

A person with schizophrenia may have trouble completing everyday tasks such as bathing, dressing appropriately and preparing simple meals. During the acute phase of the illness, people will likely be unable to plan their days and follow through with tasks that they had previously performed effortlessly.

The following symptoms may also be associated with schizophrenia:

Disturbances of feeling or affect (mood)

At times people with schizophrenia may find it hard to express their feelings. On the one hand, they may experience inappropriate or intense bursts of feeling that seem to come out of the blue. On the other hand, they may feel empty of any emotions.


Ambivalence means having conflicting ideas, wishes and feelings toward a person, thing or situation. It may be hard for people with schizophrenia to make up their minds about anything, even relatively common decisions such as what to wear in the morning. Often, even if they are able to make a decision, it may be hard to stick with.


One of the earliest symptoms in people with schizophrenia may be a change in their sensitivity toward others. They may become more sensitive and aware of other people, or they may withdraw and seem to pay no attention to others. They may become suspicious and worried that people are avoiding them, talking about them or feeling negatively toward them.

Negative symptoms

Physical symptoms

Physical activity may slow down in people with schizophrenia, sometimes to a point where they become motionless and stare into space. On rare occasions, they may become excited and overactive and experience strange body sensations.

Reduced motivation

People with schizophrenia may have problems finishing tasks or making and carrying out long-term plans. They may also have less energy and drive, both before and after an active phase of illness.

Social withdrawal

People with schizophrenia may feel safer and calmer being alone. They may also become so absorbed in their own thoughts and sensations that they lose interest in the feelings and lives of others.

Change in habits and ability to function

People with schizophrenia may become less concerned about the way they dress and lose interest in grooming and bathing. They may find it increasingly difficult to carry out daily activities such as shopping or going to work.

What causes the illness?

Schizophrenia is now recognized as a disease of the brain. No single cause has been found. Current thinking is that schizophrenia results when genetic programming is impaired. This disrupts the chemistry of the developing brain of the fetus. Research into the chemical and genetic basis of schizophrenia has provided clues in the search for better ways to diagnose and treat the illness.

CAMH Switchboard 416-535-8501
CAMH General Information Toronto: 416-595-6111 Toll Free: 1-800-463-6273
Connex Ontario Help Lines
Queen St.
1001 Queen St. W
Toronto, ON
M6J 1H4
Russell St.
33 Russell St.
Toronto, ON
M5S 2S1
College St.
250 College St.
Toronto, ON
M5T 1R8
Ten offices across Ontario