Background: Schizophrenia is consistently associated with lower IQ compared to the IQ of control groups, or estimated premorbid IQ.
Individuals with schizophrenia showed decline in IQ as well as a range of different mental functions, particularly those tapping processing speed, learning, executive functioning, and motor functioning.
A robust interaction was seen between genetic liability to schizophrenia and IQ in predicting schizophrenia risk. Genetic susceptibility for schizophrenia had a much stronger impact on risk of illness for those with low than high intelligence.
Of 129 individuals with first-episode schizophrenia or schizoaffective disorder, 25% showed stable low IQ, 31% showed stable IQ in the average/high range, and 44% demonstrated intellectual deterioration by 10 points or more.
So while treatment with some antipsychotics seems to increase intelligence, others reduce symptoms without that effect. Other medications that are known to cause improved cognitive functioning had no effect when combined with those antipsychotics.
While schizophrenia typically causes hallucinations and delusions, many people with the disorder also have cognitive deficits, including problems with short- and long-term memory.
The cause of the IQ decline is due to environmental factors, and not genetics, said Ole Rogeburg, a senior research fellow at Ragnar Frisch Centre and co-author of the study on IQ scores, published in the Proceedings of the National Academy of Sciences journal.
What are the causes of mental subnormality? Mental retardation could occur due to genetic causes such as metabolic disorders, deficiency of metabolic enzymes, hypothyroidism, syndromes such as Down's syndrome, Fragile-X syndrome, Prader-Willi syndrome.
Even though the genetic susceptibility plays a crucial role on the IQ of the individual, various modifiable environmental factors like education, premature birth, nutrition, pollution, drug and alcohol abuse, mental illnesses, and diseases can have an influence on an individual's IQ.
Schizophrenia has been described as the “worst disease” to afflict mankind. It causes psychosis, which is an abnormal state of mind marked by hyperarousal, overactivation of brain circuits, and emotional distress. An untreated episode of psychosis can result in structural brain damage due to neurotoxicity.
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.
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.
Researchers have previously shown that a person's IQ is highly influenced by genetic factors, and have even identified certain genes that play a role. They've also shown that performance in school has genetic factors. But it's been unclear whether the same genes that influence IQ also influence grades and test scores.
We concluded that prolonged intensive training in creative problem-solving can lead to substantial and positive effects on intelligence during late adolescence (ages 18–19).
As I said, IQ almost certainly comes from a combination of genes and the environment. Both can explain why a child's IQ can be so different from his or her parents'. The environment makes sense.
Just as having a high IQ doesn't ensure success, having an average or low IQ doesn't ensure failure or mediocrity. Even if you have what is considered a low IQ, you may be smart in many other ways and have many other talents and abilities that aren't reflected on a single test.
However, the lowest IQ score possible is zero. Can someone actually get this low of a score? In theory, yes. But no one in recorded history has officially scored zero on an IQ test, even if that result is theoretically attainable.
The average child's IQ is not stable until around four years of age. It may be much later in children who were born early or who have significant health issues.
IQ peaks at around 20-years-old and later effort will not improve it much beyond this point, research finds. The complexity of people's jobs, higher education, socialising and reading all probably have little effect on peak cognitive ability.
Interestingly, although significant correlations between stress and EI and between EI and IQ were found, no significant correlation between stress and IQ was observed. We can infer that this result may be related to brain structure.
People in the lower IQ range are more likely to have lower-than-average incomes, the researchers explained. There is also a higher incidence of common mental disorders and suicidal behaviors among individuals with lower IQs.
The Brain In Schizophrenia
The fluid-filled spaces (the ventricles) in the interior of the temporal lobes are often enlarged and the temporal lobe tissue diminished. The greater the observed changes the greater the severity of the person's thought disorder and his or her auditory hallucinations.
Bipolar disorder.
Some people with severe bipolar disorder have delusions or hallucinations. That's why they may be misdiagnosed with schizophrenia.
Schizophrenia (SZ) is a severe psychiatric illness associated with an elevated risk for developing Alzheimer's disease (AD). Both SZ and AD have white matter abnormalities and cognitive deficits as core disease features.
Scientists don't know exactly what causes someone to be a genius. There is probably a genetic component to your level of intelligence. Certain types of genes influence how much intellectual power you have. Your child's genetic influences affect their motivation, confidence, and other traits.