A new study has confirmed a link between antipsychotic drugs and a slight, but measurable, decrease in brain volume in patients with schizophrenia.
Researchers noted they were also able to examine whether this decrease is harmful for cognitive function, reporting that over a nine-year follow-up, the decrease did not appear to have any effect.
As we age, our brains naturally lose some of their volume. Known as atrophy, this process usually begins in our 30s and continues into old age. Researchers have known for some time that patients with schizophrenia lose brain volume at a faster rate than healthy individuals, although the reason why is unclear.
For their study, researchers from the University of Oulu, Finland, and the University of Cambridge in England identified the rate of decrease in both healthy individuals and patients with schizophrenia. They also documented where in the brain schizophrenia patients have more atrophy. Finally, they examined the links between atrophy and antipsychotic medication.
Comparing the brain scans of 33 patients with schizophrenia with 71 healthy individuals over a nine-year period — from the ages of 34 to 43 — the researchers discovered that schizophrenia patients lost brain volume at a rate of 0.7 percent each year. The healthy participants lost brain volume at a rate of 0.5 percent per year, the researchers reported.
Speculation that antipsychotic medication used to treat schizophrenia may be linked to this decrease in brain volume was confirmed by the new study, which showed that the decrease was greater when the dose of medication was higher.
However, the researchers note that the mechanisms behind this — and whether it was, in fact, the medication that was causing this greater loss of tissue — are not clear.
There also has been some speculation that older antipsychotic medications might cause brain volume decreases, while newer antipsychotic medications actually protect against these decreases. The new study, however, found that both classes of antipsychotic medication are associated with similar declines in brain volume.
The researchers also looked at whether there was any link between the volume of brain loss and the severity of symptoms or loss of cognitive function, but found no effect.
“We all lose some brain tissue as we get older, but people with schizophrenia lose it at a faster rate,” said Dr. Juha Veijola from the Department of Psychiatry at the University of Oulu. “We’ve shown that this loss seems to be linked to the antipsychotic medication people are taking.
“Research like this where patients are studied for many years can help to develop guidelines about when clinicians can reduce the dosage of antipsychotic medication in the long term treatment of people with schizophrenia.”
“It’s important to stress that the loss of brain volume doesn’t appear to have any effect on people over the nine year follow-up we conducted, and patients should not stop their medication on the basis of this research,” said Dr. Graham Murray from the Behavioral and Clinical Neuroscience Institute and the Department of Psychiatry at University of Cambridge.
“A key question in (the) future will be to examine whether there is any effect of this loss of brain volume later in life. We need more research in larger studies with longer follow-ups to evaluate the significance of these brain changes.”
The research, supported by the Academy of Finland, Medical Research Council, Sigrid Jusélius Foundation, and the Brain and Behavior Research Foundation, was published in the open access journal PLOS ONE.
Source: University of Cambridge