P300 Findings in Schizophrenia Disorder

Şizofreni Hastalığında P300 Bulguları

Schizophrenia in General

Schizophrenia is a challenging, complex and serious psychiatric disorder that hurts people. Although the symptoms of schizophrenia vary from patient to patient, these symptoms generally include deteriorations in psychosocial functionality, disorganized behaviors, hallucinations, delusions, irregular affect. In the majority of the cases encountered, the disorder generally progresses sneakily. The aforementioned symptoms do not occur all at once, but slowly. While the lifelong prevalence of the disorder is 1%, it generally starts earlier in men, and it appears in the late adolescence/early adulthood periods at the latest.

What kind of a Disorder is Schizophrenia?

Schizophrenia is not a simple disorder that can be only associated with biology, or only with psycho-development process, nor with social sphere. As mentioned, although the symptoms differ from person to person, it would be suitable to describe schizophrenia as a bio-psychosocial disorder.

Schizophrenia and Brain Relationship

The symptoms of people with schizophrenia and the functional changes in their brains seem to be seriously connected. The developing brain imaging systems have enabled a progress in revealing the functional disorders of specific areas of the brain. Even so, it is hard to say that they are able to completely reveal the fundamental neuropathology of the disorder. Functional changes have been observed in specific areas of the brain between schizophrenics and non-schizophrenics through normal controls with the use of functional brain imaging methods for each symptom, which is observed in schizophrenia as specified in the beginning of the article.

Schizophrenia and Dopamine Relationship

Under the light of the studies carried in the 1960s, the most common theories and findings regarding the etiology of schizophrenia became associated with dopaminergic brain pathways.  Within the same period, it was observed that the dopamine-reducing drugs decreased the psychotic symptoms, while dopamine-increasing drugs increased the symptoms.

Schizophrenia and P300

Besides being a bio-psychosocial disorder, schizophrenia, as it has been observed up to this point, is a disorder that is closely associated with the pathways located in the brain. EEG, one of the methods to monitor and follow developing brain functions, gives us the opportunity to assess the functional level of the brain, or whether there is a deterioration. In addition to psychiatric disorders, changes have been observed in the amplitude and latencies in P300, which is most commonly preferred in the analysis of how the brain reacts to specific stimulants through EEG.

In many studies carried out with schizophrenic patients, researchers reported that there was a decrease in the P300 amplitude, while the latency was prolonged. In addition to its feature of being an identifier in diagnosing schizophrenia, P300 provides us with data to enable us to be more sensitive for the progressive degenerative course of the disorder. Furthermore, during the studies carried out with the twins and close relatives of people with schizophrenia, the P300 amplitude of these people were found surprisingly low, and it was specified that this low P300 amplitude is useful in terms of determining the transition of the disorder.

As seen, the P300 changes in patients with schizophrenia are significant endophenotypes in terms of guiding us with regards to the commencement, treatment and follow-up of the disorder.