Schizophrenia is a mental disorder mainly characterized by abnormalities in the perception or expression of reality, usually manifesting itself in hallucinations, “voices”, paranoid delusions or disorganized speech and thinking, often with significant social or occupational dysfunction. It does not necessarily imply the “split mind” of dissociative identity disorder (also known as multiple personality disorder or split personality), but schizophrenia sufferers can experience severe difficulty in distinguishing what is real from what is not. “Noise” in the brains of schizophrenics also results in cognitive impairment, memory loss and attention deficits, resulting in difficulties in day to day functioning and learning.
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|A study of schizophrenic patients showed that, when given two different sound tones, they were unable to match two tones after a very short delay time (300 milliseconds), but were able to correctly match when there was no delay between the tones.|
This suggests that schizophrenia affects the brain regions which control echoic or auditory sensory memory outside the prefrontal cortex.
Both schizophrenia and multiple personality disorder chiefly affect biographical or episodic memory, leaving semantic and procedural memory largely accessible (to all of the person’s identities). The disorder is believed to develop as a defence mechanism against childhood deprivation or abuse or some other kind of psychic trauma. Elderly schizophrenia patients often also suffer from Alzheimer’s disease, or some other form of dementia, in varying levels of severity.
Schizophrenics often have difficulty encoding, storing and recalling words, although recent advances in the understanding of neuroplasticity have led to some promising new treatments. It has been shown that schizophrenic symptoms can be improved by stimulation, particularly through the regular repetition of some simple (although progressively more challenging) auditory and visual exercises. As brains change physically through neuroplasticity, many of the abnormal patterns in the brain which characterize schizophrenia are removed. In addition, levels of the protein BDNF (brain-derived neurotrophic factor), which is lower than normal in schizophrenics, are also increased to near-normal levels. Similar treatments may even be used to prevent the onset of schizophrenia in people exhibiting early warning signs of the disorder.
Studies have shown that schizophrenic patients not currently taking related medication have smaller putamen (part of the striatum that plays a very important role in procedural memory), as well as improper communication from the basal ganglia part of the brain. Although it is thought that functional problems in the striatum of schizophrenic patients are not significant enough to seriously impair procedural memory, the impairment may be significant enough to cause problems in the improvement of performance on a task between practice intervals.