Men who frequently watch porn often have less activity in regions of the brain associated with motivation.
Researchers are not sure if watching pornography leads to less brain activity and matter or if people with this brain type tend to watch more porn, Reuters reported.
"Unfortunately we cannot answer this question based on the results of the present study," Simone Kühn, the study's lead author from the Max Planck Institute for Human Development, told Reuters.
The researchers looked at 64 healthy men between the ages of 21 and 45. They asked them questions about their porn watching habits and took images of their brains.
"We found that the volume of the so-called striatum, a brain region that has been associated with reward processing and motivated behavior was smaller the more pornography consumption the participants reported," Kühn said.
"Moreover we found that another brain region, that is also part of the striatum that is active when people see sexual stimuli, shows less activation the more pornography participants consumed," she said.
The connection between the striatum and prefrontal cortex, which deals with decision making, also worsened with excessive porn watching.
The study cannot prove whether or not porn watching is actually harmful because they are not sure if it actually causes brain changes.
"Everything is going to be bad in excess and it's probably not terrible in moderation," Doctor Gregory Tau of the Columbia University and New York State Psychiatric Institute in New York told Reuters.
"It is possible that there are individuals with a certain kind of brain that are more susceptible to these kinds of behaviors," Tau said. "Or, it's possible it's the excessive use (of porn) that's perpetuating itself to causing brain changes. Or, it could be both."
Other behaviors such as frequent driving have been shown to cause brain changes in the past.
