Recreational drugs can wreak havoc on anyone’s life. But for those with mental illness, smoking pot could lead to aggressive behavior—and put their loved ones at risk.

According to a new study published in September in Frontiers in Psychiatry, adults who persistently smoke marijuana following a psychiatric hospitalization are 2½ times more likely to commit violent acts, including assault, battery, or threats with a weapon, than those who do not use the drug.

The study included 1,136 patients from ages 18 to 40 who received five follow-up appointments within a year after discharge from a psychiatric hospital. Not only did the researchers find that cannabis use put these patients at an increased risk for violent behavior, but they also discovered the risk is greater than for those using other mood-altering substances. “An interesting feature of our results is that the association between persistent cannabis use and violence is stronger than that associated with alcohol or cocaine,” Alexandre Dumais, the lead researcher, said in a statement.

The results support neuroimaging studies that show chronic marijuana users develop deficits in the prefrontal cortex, an area of the brain involved in inhibiting impulsive behavior, the researchers said. Problems with the prefrontal cortex have been correlated with antisocial personality and psychopathic traits.

The National Institute on Drug Abuse reviewed numerous studies on the adverse effects of cannabis use. They found that short-term effects may include impaired memory, decreased problem-solving ability, hallucinations, and delusions. Possible long-term effects include breathing problems, increased heart rate (which may raise the risk of a heart attack), onset or worsening symptoms of mental illness, depression, anxiety, and brain and behavioral problems for unborn and nursing babies whose mothers use the drug.

On a restricted diet

In Florida’s Everglades, Burmese pythons are exploding in number and decimating native wildlife. Pythons, which experts believe first arrived in the Everglades as exotic pets, reproduce quickly and feast on raccoons, marsh rabbits, opossums, and birds. In fact, Everglades pythons have feasted so well that mosquitoes are now forced to get their blood dinners mostly from the cotton rat, a species known to carry a mosquito-borne virus that can cause fever, headache, and in rare cases encephalitis in humans.

In a study published in the October issue of Biology Letters, researchers sampled the gut DNA of mosquitoes and compared the results with data from a similar 1979 study—conducted long before the Burmese python invaded the Everglades. They found that in 1979 mosquitoes took only 15 percent of their blood meals from the cotton rat, compared with 77 percent in 2016. Researcher Nathan Burkett-Cadena warned that the mosquitoes’ changing diet could mean an increase of the spread of the Everglades virus. —J.B.

Gold boom

Astronomers have detected for the first time gravitational waves produced by the collision of two neutron stars.

When the neutron stars crashed into each other on Aug. 17 (as seen from Earth), they created heavy elements such as gold and platinum and hurled them into space. Daniel Kasen, a theoretical astrophysicist at the University of California, Berkeley, told NPR this star collision produced around 200 Earth masses of pure gold and 300 Earth masses of platinum.

The matter in a neutron star, formed when the core of a massive star collapses, is so dense that a sugar-cube-sized piece would weigh more than a billion tons. —J.B.