Schizophrenia is associated with changes in the structure and functioning of a number of key brain systems, including prefrontal and medial temporal lobe regions involved in working memory and declarative memory, respectively.
The most common theory about the cause of schizophrenia is that there are too many dopamine receptors in certain parts of the brain, specifically the mesolimbic pathway. 1 This causes an increase in mesolimbic activity which results in delusions, hallucinations, and other psychotic symptoms.
Some of the most interesting findings of structural MRI and fMRI studies with schizophrenic patients include decreased gray matter (frontal lobe) volume, and reduced brain activity and volume.
Studies show that certain brain chemicals that control thinking, behavior, and emotions are either too active or not active enough in people with schizophrenia. Doctors also believe the brain loses tissue over time.
The authors hypothesize that schizophrenia is characterized by abnormally low prefrontal dopamine activity (causing deficit symptoms) leading to excessive dopamine activity in mesolimbic dopamine neurons (causing positive symptoms).
Some studies have found abnormal levels of estrogens and testosterone in schizophrenia patients, but the results have been inconsistent and sometimes attributed to the hyperprolactinemia effect of antipsychotics, which may interfere with sex hormones production.
Research suggests schizophrenia may be caused by a change in the level of 2 neurotransmitters: dopamine and serotonin. Some studies indicate an imbalance between the 2 may be the basis of the problem.
Hippocampal function. The metabolism and blood flow of the hippocampus are increased at baseline in schizophrenia. Furthermore, hippocampal and parahippocampal rCBF is increased during the experience of psychotic symptoms and correlates with positive symptoms (delusions, hallucinations).
Highly stressful or life-changing events may sometimes trigger schizophrenia. These can include: being abused or harassed. losing someone close to you.
Brain imaging shows that people with schizophrenia have less gray matter volume, especially in the temporal and frontal lobes. These areas of the brain are important for thinking and judgment. What's more, gray matter loss continues over time.
Poor learning and retention of verbal information is a hallmark cognitive impairment in schizophrenia. Along with executive functioning deficits, impaired ability to encode and retain verbally presented information is one of the most consistent findings across research studies.
Background: Schizophrenia patients are typically found to have low IQ both pre- and post-onset, in comparison to the general population. However, a subgroup of patients displays above average IQ pre-onset. The nature of these patients' illness and its relationship to typical schizophrenia is not well understood.
Background: Schizophrenia is consistently associated with lower IQ compared to the IQ of control groups, or estimated premorbid IQ.
Compared with healthy subjects, schizophrenic patients may also have increased levels of serotonin and decreased levels of norepinephrine in the brain.
Bipolar disorder.
Some people with severe bipolar disorder have delusions or hallucinations. That's why they may be misdiagnosed with schizophrenia.
Moderate quality evidence also found a medium to large effect of reduced prefrontal serotonin 5-HT2A receptors in people with schizophrenia.
Some experts believe that sensitivity to wheat can be a factor in mental health conditions like schizophrenia. One study suggests some people with schizophrenia had their condition improve when they switched to a gluten-free diet. Gluten is a protein found in wheat and other grains.
Research suggests that schizophrenia occurs due to a combination of genetic and environmental factors, which can cause abnormal development in the brain. In people with these risk factors, severely stressful life events, trauma, abuse, or neglect may trigger the condition.
The dopamine hypothesis of schizophrenia postulates that hyperactivity of dopamine D2 receptor neurotransmission in subcortical and limbic brain regions contributes to positive symptoms of schizophrenia, whereas negative and cognitive symptoms of the disorder can be attributed to hypofunctionality of dopamine D1 ...
It is clear that some of the cognitive disturbances that are present in a person with schizophrenia are associated with serotonin deficiency. Abnormalities of the brain structure such as a decreased prefrontal and medial temporal lobe, as well as enlarged ventricles are also attributed to schizophrenia.
While schizophrenia typically causes hallucinations and delusions, many people with the disorder also have cognitive deficits, including problems with short- and long-term memory.
Compared to controls, patients with schizophrenia had significantly smaller gray matter intracranium and total brain volumes, increased 4th ventricle volumes, and greater temporal and occipital ADCs.
Compared to their healthy counterparts in the general population, individuals diagnosed with schizophrenia are 4 to 6 times more likely to commit a violent crime. In Western countries, 6% of the homicide perpetrators in the populations were labeled schizophrenic.
Previous studies have found that patients with full-blown schizophrenia lack self-awareness of illness (4, 10). About 46% of FEP patients showed poor insight (11) and insight impairment is associated with multiple cognitive deficits (12).