Nicotine can normalise brain connections that are disrupted in schizophrenia, new research finds.
It could help to explain why those with schizophrenia frequently smoke so heavily.
Around 90% of those suffering from schizophrenia are smokers.
This compares to a rate of around 20% of the general population and around 50% for those with mental health problems.
Many speculated that they could be self-medicating.
The research could eventually lead to a new treatment for schizophrenia that is non-addictive.
Dr Jerry Stitzel, one of the study’s authors, said:
“Our study provides compelling biological evidence that a specific genetic variant contributes to risk for schizophrenia, defines the mechanism responsible for the effect and validates that nicotine improves that deficit.”
The study was carried out on mice genetically engineered to have schizophrenic characteristics.
Giving them nicotine increased their brain activity to normal levels over the period of a week.
Dr Stitzel said:
“Basically the nicotine is compensating for a genetically determined impairment.
No one has ever shown that before.”
At the heart schizophrenia is believed to be a phenomenon known as hypofrontality.
This is the abnormally low firing rate of neurons in the prefrontal cortex.
This likely leads to the main psychological problems for those with schizophrenia, including:
- problems making decisions,
- difficulty paying attention,
- and memory problems.
Nicotine bring this firing rate back to normal — in mice at least.
Studies on people with schizophrenia, though, have suggested that nicotine works in a similar way on the human brain.
Uta Waterhouse, a PhD student, has studied the effects of smoking on those with schizophrenia.
“In pre-clinical studies, I found that nicotine improved the cognitive deficits associated with schizophrenia.
[they] clearly showed that nicotine has a positive effect on the problematic changes to brain function that come with schizophrenia.
This explains why so many patients with schizophrenia are smokers: It’s a way of self-medicating,”
ADHD and other disorders
Not only is hypofrontality linked to schizophrenia, it is also important in ADHD, bipolar disorder, addiction and other mental health problems.
The development of nicotine-based treatments could help these other conditions as well.
The new study was published in the journal Nature Medicine (Koukouli et al., 2017).
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