The age-old belief goes that alcohol helps people drown their sorrows, but in truth the bottle only makes bad memories linger, a Japanese study said Friday.
Researchers at the University of Tokyo concluded that ethanol -- an intoxicating agent in alcohol -- does not cause memory to decrease, as widely believed, but instead locks it in place.
The researchers, led by pharmacology professor Norio Matsuki, gave mild shocks to lab rats to condition them to fear. As a result, the rats would freeze in terror and curl up the moment they were put in their cages.
Researchers then immediately injected the rats with ethanol or saline.
The researchers found that rats with alcohol in their veins froze up for longer, with the fear on average lasting two weeks, compared with rats that did not receive injections.
"If we apply this study to humans, the memories they are trying to get rid of will remain strongly, even if they drink alcohol to try to forget an event they dislike and be in a merry mood for the moment," the study said.
"The following day, they won't remember the merriness that they felt," it said.
Matsuki said the findings offered lessons for people living with bad memories.
"To forget something you dislike, it's best to overwrite the negative memory with a positive memory at an early stage and leave out drinking alcohol," Matsuki advised.
The study was published in the US academic journal Neuropsychopharmacology.