Caitie Keyes-Liley, 20, was used to hangovers - the headache, nausea, dry mouth, dizziness. But then a new symptom emerged. Panic.
The day after big drinking sessions she found herself replaying events of the night before, obsessing over gaps in her memory. She was paranoid she had done something badly wrong.
''I've [twice] had a panic attack when hung-over,'' says Keyes-Liley, who now works as a librarian. ''One was immediately when I woke up, whereas the other was in the middle of the day when I'd had more time to think about [the night before].''
Keyes-Liley says she didn't realise at first that her feelings of guilt and embarrassment were extreme. ''I sort of accepted that that's what a hangover was, that you'd feel quite horrible about yourself.''
Emerging international research suggests she is only one of many drinkers who face persistent, unwanted thoughts after a night of boozing.
A study of 1400 Dutch students aged 18 to 30, published in March in the journal Alcohol and Alcoholism, found 8 per cent suffered anxiety during hangovers. More than a third of participants reported disorientation and half said they felt agitated.
A co-author of the study, psychologist Dr Adele McKinney, says it is clear that alcohol continues affecting the brain even after it has left the body.
It's not the first study to report the correlation. In 2006, McKinney, a lecturer at the University of Ulster in Northern Ireland, found ''high levels of anxiety'' in 48 healthy but hungover students.
The heavier drinkers, who weren't more stressed than average at the beginning of the study, suffered worse emotional distress the day after drinking.
McKinney is concerned by a lack of public knowledge about the link between binge drinking and anxiety. ''An escalation of awareness needs to occur,'' she says.
The Australian Medical Association reports the majority of Australians drink alcohol at levels that involve a risk of harm. The problem is worst among the young - 80 per cent of the alcohol intake of 18- to-24-year-olds is consumed at risky levels.
Mental health awareness groups, such as Beyondblue and Headspace, say that those with mental illnesses are more likely to drink to overcome negative emotions. They also warn that long-term alcohol abuse can cause anxiety and depression.
But the findings of McKinney and others suggest short-term alcohol abuse can also have mental health consequences, even for those with no history of mental illness.
End-of-year celebrations that offer regular and sustained drinking opportunities, including schoolies and Christmas parties, may be hazardous in ways not previously acknowledged.
A psychiatrist and associate professor at Flinders University in Adelaide, Dr Michael Baigent, who is also a national clinical adviser to Beyondblue, says alcohol can have a ''rebound effect'', leaving people feeling on edge.
''As the alcohol wears off, you lose the sedating effect,'' Baigent says. He describes how the body metabolises alcohol into acetaldehyde, a chemical compound that produces ''very nasty symptoms'' such as a fast pulse and anxiety.
Law student Will (who did not wish to be identified by his real name) says being hung-over can mean hours of feeling upset and stressed. ''It's more than being hung-over or a little bit down,'' he says. ''It's like you're against yourself.''
Like Keyes-Liley, Will often fixates on events of the night before. ''I do become really worried and anxious,'' he says. ''It's happened a couple of times with me where I need to call and talk to people and apologise.
''But then it's not an issue with them. It's more my anxiety, my paranoia, that I've done something or offended someone.''
A US blogger who has a master's degree in psychology, Paul Dooley, tells how drinking precipitated his first panic attack.
''After a night of drinking with friends, my life changed forever,'' he writes on his mental health blog, anxietyguru.com. ''I remember reading a magazine and having nothing really on my mind, when I suddenly became overwhelmed with feelings of fear and confusion. After that night I stayed anxious for nearly six months straight.''
In online health forums, many people describe hangovers that involve overwhelming anxiety symptoms, such as difficulty breathing, racing heart rates and fears of insanity or death.
So what should drinkers do if they experience a panic attack? A Brisbane psychologist, Santo Russo, says sufferers should understand that anxiety during a hangover is a product of the alcohol. ''This is not you,'' Russo says. ''Affirm for yourself that this will pass. Calm yourself - focusing on breathing is one important option to look at.''
While most people when hung-over will want to lie in bed, curled up in the foetal position, Russo says a distraction can also be really helpful.
''You are better off trying to keep commitments, including work, the next day.''
Baigent says that while people should always seek help for mental problems, including recurrent anxiety after drinking, ''no psychiatric treatment will be better than reducing the alcohol you're drinking''.
''No amount of cognitive behavioural therapy or anti-depressants will make a difference if you're not cutting down,'' he says. Baigent worries that many people who enjoy alcohol to reduce inhibitions will dismiss the next day's woes, ''more enamoured by the help it gave them the night before''.
Russo is also concerned by the peer pressure associated with drinking. He says people who want to feel part of the group when drinking can succumb to pressure ''knowing that negative feelings the next day can be hidden''.
Instead, Russo says, people at risk of an anxious hangover need to have a plan and stick to it. ''Let your friends know, 'I'm only having two drinks.' When they say, 'Oh come on,' you have to feel strong enough to say, 'No, it's not worth it.'
''Very few groups will ostracise someone for not keeping up. And if they do, you have to ask yourself, 'Do I really want to be a part of this group?'''
Russo warns that drinking again the next morning is a ''huge trap''.
''Anyone who engages in that is setting themselves up for a problem. That's how alcoholism starts. If the whole pattern is persisting, it's important to actually seek help.''
Will admits he still drinks a lot. ''But I do cut it down after I've had an episode. It's pretty exhausting. On top of having a hangover you're mentally exhausted.''
But Keyes-Liley says after a bender earlier in the year she has drastically reduced her drinking. She can now resist the pressure to drink, even though ''it's such a social norm''.
''I haven't had a bad hangover in a really long time because I deliberately haven't had a big night. Now I can go out and not have a lot to drink.''
Weathering the storm
Try to remain calm
Reassure yourself that the anxiety is a product of the alcohol consumed and will pass.
Go to work and keep other commitments.
Drinking to reduce social anxiety can set you up for an anxious hangover; drinking to handle an anxiety hangover can set you up foralcoholism.
Ask peers for their support in not encouraging you to drink to risky levels; seek professional help for persistent heavy drinking and anxiety.