It is known that the negative symptoms that can appear because of schizophrenia reflect lack of emotions, colorless speaking tones, diminishment of the self and a general loss of interest in life and the ability to experience pleasure. It was also seen that patients can display inappropriate reactions to an event.
In many cases, certain negative symptoms can appear in childhood, and be the first signs of schizophrenia. In many patients, negative symptoms occur only after positive symptoms, and in older patients, negative symptoms tend to be more common than positive symptoms, persisting even after positive symptoms have been treated.

It was seen that the most widely recognized manifestations of schizophrenia are delusions and hallucinations.
Those who have hallucinations experience seeing, hearing, tasting, smelling or feeling things that do not exist in reality. Auditory hallucinations, in which the patients hear voices others don't affects 70% of the people with schizophrenia.
Delusions are false beliefs, the patients think a lot of bizarre things, for example they can believe the aliens are here and will harm them.
After the initial event, psychotic symptoms appear episodically, and are interspersed with periods of remission.

Cognitive impairment, has symptoms that may occur before other symptoms of schizophrenia. We can mention a lack of attention, and an aberrant association between words and ideas, impaired information processing. There can appear memory impairments- a patient may recall and even feel a familiarity with a specific event but cannot remember anything about it.
There can also appear the backward masking dysfunction. This can be an important symptom and a marker of schizophrenia; a distraction causes a person to forget a preceding event. We can describe a test that is used to diagnose this trait: on a computer screen, the patient is given an item to look at, and then the screen goes blank and another image called the masking stimulus appears. After this, the patient is being asked about the first image.

As a conclusion, we can say that people with schizophrenia have problems when dealing with mental tasks requiring conscious awareness, such as verbal fluency, short-term and working memory, and processing speed. There are experts that believe impaired verbal memory in schizophrenia appears because of depression and slowness, and is not a result of the disease process.
Schizophrenia is a chronic, severe, and disabling brain disease, but there are made intense researches to discover more about this illness and its complex causes, and in the future there is hope for better treatments and even for a cure.