Brain Function can Recover after a Year of Abstinence from Methamphetamine
“Recovery from meth abuse does not happen overnight,” said Ruth Salo, lead author of the study and a UC Davis assistant professor of psychiatry and behavioral sciences. “It may take a year—or even longer—for cognitive processes such as impulse control and attentional focus to improve,” she said. “Treatment programs need to consider this when monitoring recovering addicts’ progress during their early periods of abstinence.”
Salo said that methamphetamine addiction is particularly difficult to treat due to prolonged, intense cravings for the drug. Salo specializes in the behavioral, neuropsychiatric, and cognitive outcomes of methamphetamine addiction and has worked with hundreds of meth addicts.
"All of them want to know if there is hope," Salo said. "We used to think most, if not all, effects of meth addiction were permanent. This study adds to the growing evidence that this assumption is not true. I can confidently tell patients that the longer they stay in a structured rehabilitation program and remain drug free, the more likely it is that they will recover some important brain functions."
In the study, Salo used the computer-based Stroop attention test to measure the abilities of 65 recovering methamphetamine abusers to use cognitive control (or direct their attention to specific tasks while ignoring distractors). Participants had been abstinent from methamphetamine for a minimum of 3 weeks and a maximum of 10 years, and had previously used the drug for periods ranging from 24 months to 28 years. The data for the 65 individuals were compared to Stroop attention test data from 33 participants who had never used methamphetamine.
“The test taps into something people do in everyday life: make choices in the face of conflicting impulses that can promote a strong but detrimental tendency," Salo said. "For meth users, impairments in this decision-making ability might make them more likely to spend a paycheck on the immediate satisfaction of getting high rather than on the longer-term satisfaction gained by paying rent or buying groceries."
The researchers found that those who were recently abstinent (3 weeks to 6 months) performed significantly worse on the Stroop test than those who had been abstinent for one year or longer. There was no statistical difference between test results for those abstinent for at least one year and non-drug users. The longer the individual used meth, the worse the test scores were, but the longer the individual abstained from meth, the better the scores.
The new study mirrors previous MRI studies Salo and her colleagues published in 2005, which showed a partial normalization of chemicals in certain brain regions after one year of abstinence from methamphetamine.
"Together, the studies provide strong evidence that, eventually, meth abusers in recovery may be able to make better decisions and regain the impulse control that was lost during their drug use period," she said.
Salo plans to continue neuroimaging studies to further define the brain functions affected by the drug. Her ultimate goal is to provide information essential to refining treatment programs for methamphetamine users.
"Meth use worldwide is pandemic," she said, referring to the estimated 35 million people who have used methamphetamines or similar drugs. "Recovery is difficult, but possible. The point of my research is to better understand the neural and behavioral consequences of this toxic drug along with the brain and behavior changes that are possible with long-term abstinence."