The cost of binge drinking Attacking anxiety

Could the damage done by long-term alcohol abuse be reversed? The latest work by Christina Perry offers promising results for those wanting to break the cycle of addiction.

Dr Christina Perry paid her way through university by working behind the bar at a Sydney pub. Night after night, she would see locals come in and drink large quantities of beer and spirits. Over the next decade, years after she had finished working at the pub but still lived nearby, she saw the rapid ageing and deterioration of young men who were now hardened drinkers.

Fast-forward to her lab bench at the Florey in Parkville, and Christina is not only trying to determine exactly how much cognitive deterioration binge drinking may cause, but whether such damage is repairable.

By exposing rats to high levels of alcohol three times a week, she has replicated the kind of harmful binge drinking found in many cultures, including Australia. Rats and humans share a very similar limbic system, the part of our brain supporting emotional behaviour, motivation and long-term memory. Because our limbic systems are similar, results of experiments on rats are particularly relevant to humans, providing a very useful insight into alcohol’s damage to the human brain. Rats are assessed for cognitive flexibility as they perform tasks on touch screens (think of an iPad for rats). Christina has found that alcohol-exposed rats find it more difficult to process changes and struggle to adjust their behaviour accordingly.

Christina joined the Florey in 2012 to work on addiction with Professor Andrew Lawrence, in the Behavioural Neuroscience division. After exploring why people became addicted to cocaine or alcohol, and studying how often and why they relapsed, she realised a longer term study could be significant.

“People with higher cognitive function are more likely to recover and not relapse, as they rationally know the harm they are doing themselves and their family,” she says.

“But long-term binge drinking also causes cognitive decline by affecting the parts of the brain in charge of rational thought and reasoning. Problem drinkers find it hard to abstain because they can’t think their way past a reflexive desire to drink.”

Simply walking past a hotel or seeing a beer label can be enough to trigger a problem drinker to break a period of abstinence. Significantly, the passing of time may actually weaken the drinker’s resolve as cravings become more intense.

So a question remains – how can our research help alcoholics overcome these triggers?

Christina’s research is now exploring whether neurological recovery is possible in the hippocampus and the pre-frontal cortex, once alcohol has done long-term damage.

Working with the rats, Christina is hoping to help people by investigating the effectiveness of exercise, combined with abstinence from alcohol, behavioural therapy and anti-craving drugs. This approach may help a person overcome their addiction and hasten the physical repair required to undo the cognitive damage.

“Exercise can lead to neuronal growth and also increase plasticity, which is the ability to learn new things and make new connections. Also in animals and humans, we know that exercise overcomes anhedonia – the inability to feel pleasure – associated with withdrawals. It also helps to deal with some of the mood effects associated with withdrawal and rehabilitation,” she says.

Most parents work out pretty quickly that their teenagers’ brains work very differently to their own. Adolescents are resistant to our wise advice and often seem to have a unique sense of logic.

While the inner life of a teen can be a mystery, researchers at the Florey are trying to work out the role of anxiety – a significant issue with 25 per cent of adolescents struggling with the problem. While we all experience anxiety, and sometimes it is an appropriate survival mechanism, new Florey research suggests adolescents are physically unable to turn off the emotion, or to work through it as an adult may.

It all comes down to something called ‘fear extinction’, according to Dr Despina Ganella, a post-doctoral fellow in Dr Jee Hyun Kim’s Developmental Psychobiology laboratory.

Fear extinction is a term used to describe the experience of learning that a previously fearful experience is not actually harmful. Repeated exposure helps the brain to match the potentially fearful stimuli with the fact that nothing bad has actually happened or is likely to happen again. In other words, we relax around the issue that once scared us because we realise the original perceived threat no longer exists.

Despina says that adolescents do not learn these new associations as well as adults. While exposure therapy remains the most effective treatment for debilitating anxiety – whether it’s being afraid of public speaking, walking into a party or entering a dark room – it is much less effective for adolescent brains.

“We are asking: ‘What’s different in an adolescent brain that makes a child so vulnerable to anxiety peaks and also so resistant to exposure therapy?’. “We’ve found that healthy adult and adolescent brains have differences in their activation patterns in brain regions that are important for effective fear extinction.”

From the age of 13, adolescents are going through a dynamic period of brain development with fundamental synaptic and structural changes occurring in the ventromedial prefrontal cortex. Despina has found that the prefrontal cortex is unable to calm down, or inhibit, the brain’s fear centre.

“Fear memories are really strong,” Despina says. “When they compete with safety memories, they can be very tough to beat. We want to understand the adolescent brain so we can design treatments and more effectively treat anxiety at that age.”

If we can treat the cause of anxiety when it occurs in a young person, he or she is more likely to leave it behind and live without the fear in adulthood. If left untreated, it can be very hard to remove.