These symptoms were seen in mice when they were exposed to low-dose radiation for six months.
With a round trip to Mars expected to take up to two years to complete, if similar behavioural traits were recorded in astronauts it could cause significant problems.
The research team included scientists from the University of California, Irvine, Stanford University, Colorado State University and the Eastern Virginia School of Medicine.
They said that their results highlight the pressing need to develop safety measures to protect the brain from radiation during deep space missions.
Radiation is already known to disrupt signalling among other processes in the brain. However, previous experiments used short-term, higher dose-rate exposures of radiation, which does not accurately reflect the conditions in space.
It was discovered that the mice experienced impaired cellular signalling in the hippocampus and prefrontal cortex, resulting in learning and memory impairments. They also observed increased anxiety behaviours, indicating that the radiation also impacted the amygdala.
The researchers predict that during a deep space mission approximately one in five astronauts would experience anxiety-like behaviour and one in three would experience certain levels of memory impairments. Additionally, the astronauts may struggle with decision-making.
“Simulating the space radiation environment to date has been limited by available technology and restricted by the practicalities of implementing protracted terrestrial-based exposures,” the scientists said in the journal eNeuro.
“Now through the use of a new neutron irradiation facility, capable of simulating the realistic low dose rates found in deep space, we have uncovered striking neurobehavioral and electrophysiological defects in rodents subjected to continuous (six-month) low dose rate (1 mGy/day) neutron exposures.”
US President Donald Trump is reportedly very keen to send astronauts to Mars and offered Nasa “all the money you could ever need” to achieve the feat.