14 DAY TRIAL // University of Zürich scientists found a series of tantalizing evidence in a new study, suggesting that smoking cigarettes may constitute a risk factor for the development of schizophrenia in patients.
Schizophrenia is a condition characterized by auditory hallucinations, paranoid and bizarre delusions, disorganized speech and thinking, poor emotional responsiveness, and a breakdown in common thought processes, and can lead to severe social impairment.
In the study, investigators found that people who smoke, those with certain genetic factors, as well as those who display difficulties in processing auditory stimuli, are more likely to develop the condition.
For several years now, researchers have hypothesized that schizophrenia can be caused by hereditary transmission from parents to offspring (in some cases). However, despite their best efforts, they have been unable to find the gene that underlies this transfer.
Rather than comparing the genetic makeup of schizophrenia patients, as opposed to that of healthy individuals, scientists in Switzerland took a different approach – they asked test subjects to listen to sequences of similar clicks (simple acoustic stimuli).
As this was happening, the team was recording participants' brain activity with a technique called EEG (electroencephalography), which analyzes brain wave patterns. Scientists suspected that patients suffering from schizophrenia are unable to filter out other stimuli while processing the sounds.
In healthy individuals, if the brain is asked to process a certain stimulus, it tends to ignore other stimuli that may run in parallel, therefore allowing that person to focus on the task at hand. If this filtration mechanism is damaged, then the brain may simply receive too much information at any given time.
The group also looked at how the presence of an altered form of the transcription factor 4 (TCF4) gene and smoking affected participants' ability to process simple acoustic stimuli. The team found that people who smoke a lot display an impaired ability to handle these stimuli, PsychCentral reports.
“Smoking alters the impact of the TCF4 gene on acoustic stimulus filtering. Therefore, smoking might also increase the impact of particular genes on the risk of schizophrenia,” University of Zürich psychiatrist Boris Quednow, PhD, explains.
“Smoking should also be considered as an important cofactor for the risk of schizophrenia in future studies,” the investigator concludes.