Seoul, Feb 12 (IANS): Abuse of the recreational drug methamphetamine decreases thickness in the gray matter of younger users' frontal cortex, the area of the brain believed to direct people's ability to organise, reason and remember things, says a study.

The researchers found that adolescents who chronically use methamphetamine suffer greater and more widespread alterations in their brain than adults.

The damage is particularly evident in a part of the brain believed to control the "executive function", the findings said.

"It is particularly unfortunate that meth appears to damage that part of the brain, which is still developing in young people and is critical for cognitive ability," said In Kyoon Lyoo from Ewha W. University in Seoul, South Korea.

For the study, the researchers scanned the brains of 111 South Korean adolescents and 114 adults.

Brain scans showed that the gray and white matter of chronic adult meth users showed far less damage than that of the adolescents.

The researchers found the evidence of damage to cortical thickness in the frontal cortex of adolescent users alarming.

"Damage to that part of the brain is especially problematic because adolescents' ability to control risky behaviour is less mature than that of adults," Lyoo said.

The results also indicate that it might take much less meth to cause greater damage in adolescent brains because youths typically use smaller amounts of the drug than adults.

Meth is the one of the most widely abused drugs in Asia.

The study appeared online in the journal Molecular Psychiatry.