PPI is an objective measure to assess pre-attentive processes that have already been tested before in the case of schizophrenia. The investigators aim to assess through this instrument two main characteristics, that the investigators assume are of relevance which are the duration of illness and the type of pharmaceutical treatment, patients receive.

The investigators believe these two main characteristics are critical to the ability of the patients in improvement of their PPI response to startle reflex.

It is common to relate changes of PPI to startle reflex to both negative and positive signs of schizophrenia. Results can both start to explain formations of delusions and hallucinations and the difficulty in processing information for surrounding. It was already tested and discussed in previous trials the relation between type of pharmaceutical treatment as affecting on PPI to startle reflex both causing changes, or improving previous results.

In previous trials as opposed to our planned trial, not much attention was paid for the relation on the changes found to the type of treatment and the duration of the illness. Plus, most trails had different methods of assessing it than our method.

The investigators assume that patients who are receiving typical antipsychotic treatment would have a reduced PPI response to startle reflex compared with those with atypical antipsychotic treatment and those with longer duration of illness would also have reduced PPI response to startle reflex in comparison to those with shorted duration of illness.

The investigators aim to enroll patients already diagnosed with schizophrenia that would be sent by their psychiatrist to the trial. In addition the investigators would enroll control group, not diagnosed with any psychiatric condition.

For both groups, the investigators would run PPI trials according to a unified protocol.

In addition the investigators would run several questionnaires for the group of the patients. Among the details asked of the patient are the duration of the illness and the type of antipsychotic medications they are on and the dosage. Data will then be analyzed.

Patients diagnosed with schizophrenia

Inclusion Criteria:

1. Patients diagnosed with schizophrenia or schizoaffective disorder according to Diagnostic and Statistical Manual (DSM) or International Classification of Diseases (ICD).
2. Patients on antipsychotic medications either typical or atypical
3. Patients older than 18 years old and younger than 90 years old
4. In psychiatric follow-up

Exclusion criteria:

1. Patients with earing problems
2. Patients who went through Invasive brain procedure
3. Patients diagnosed with mental retardation
4. Patients with psychoactive substances abuse
5. Pregnant women
6. Patients receiving or received electroconvulsive therapy
7. Patients who have had any medication's regimen changes in either type or dosage in the last month before trial
8. Patients on hormonal therapy

Healthy subjects:

Inclusion criteria:

1. Subjects with no known psychiatric condition
2. Subjects older than 18 years old and younger than 90 years old

Exclusion Criteria:

1. Subjects with earing problems
2. Subjects who went through Invasive brain procedure
3. Subjects diagnosed with mental retardation
4. Subjects with psychoactive substances abuse
5. Pregnant women
6. Subjects on hormonal therapy
7. Subjects with unstable physical status
8. Subjects on psychoactive drug
9. Subjects who have spent time abroad where there is at least 2 hours zone time difference from Israel