But what happens when the problems aren't just related to 'festive' and new year celebrations booze, but spill over into the rest of the year? How much of a concern are these problems? What if any harder drugs are involved? And how should an employer tackle the issues involved?
The TUC estimates that between 3% and 5% of all work absences are due to alcohol, which costs the UK economy nearly £2 billion a year. Recent research from drug and alcohol screening provider Concateno reveals that one in 30 employees (3.23% of the 1.6 million UK employees it tested in 2011) has drugs in their system at any one time in the workplace. If that figure were extrapolated for the UK population, it would equate to 940,000 people. And a 2012 survey by law firm Blake Lapthorn found that most organisations think the use of alcohol (61%) and drugs (54%) by employees outside the office has an adverse effect on their work.
The effects don't stop at the costs of absenteeism, reduced productivity, errors and underperformance. They also encompass potentially disastrous health and safety issues - for the individual, their colleagues and the public - as well as the legal implications for the company. UK businesses can't just stick their heads in the sand: they need to address the issue or leave themselves vulnerable.
According to Dr Kostas Agath, medical director of specialist drug and alcohol treatment charity Addaction, treating the workplace as a place to tackle drug and alcohol misuse is an important preventative measure, and has been a long time coming. "The emphasis was always on extreme drug use," he says. "Services used to be targeted at places identified as being where people with a problem might be, such as hospitals, and the workplace was neglected."
But in the past decade the focus has changed, says Agath. The workplace is now viewed as a place where potential problems can be diagnosed as well as nipped in the bud, saving financial, social and emotional costs. However, he points out that attitudes, potential consequences and chances of detection still vary greatly between sectors.
"When you don't have strict supervision in place, a problem is much more likely to go undetected," he says. "Access to certain drugs and the ability to afford them, yes, these are important, but the single most important factor is the length of time you can stay under the radar. Pilots, even accountants, for example, would be picked up immediately; doctors or lawyers much less so."
He also points out that the difference in risk - both in danger and in career jeopardy - can also be a factor, as can work culture. The long-term career ramifications of a police officer taking an illegal substance are likely to be tougher than for someone working in the media, for example. And someone working in the advertising industry, with vestiges of a Mad Men-esque reputation for fast living still lingering, is likely to find colleagues less condemnatory than a heart surgeon.
These factors may explain why there is such a wide range in approach to drugs and alcohol. The most recent CIPD survey (in 2007, of 505 organisations employing a total of more than 1.1 million people) on the subject found that, overall, more than 40% of organisations had no declared rules in place about the possession of drugs and alcohol on the premises. A similar proportion had no specific policy on drug and alcohol problems. Those that did often communicated this solely via the staff handbook - all too easily consigned to a drawer after induction, never to be looked at again.
Again, there are differences between sectors. Almost three-quarters of safety-critical organisations, such as transport and logistics companies, did have health and safety policies that referred to drug and/or alcohol problems.
It's an approach that Fiona Martin, director and head of the employment department at law specialists Martin Searle Solicitors, recommends. "The starting point in dealing with the issues should really come as early as possible, with some sort of policy," she says. "The right approach is to have clear boundaries with a lot of support before you go near any disciplinary route."
Martin recommends a policy statement that promises commitment to providing a safe, healthy and productive working environment - but also indicates avenues of support. One that outlines clearly who is covered by the policy and what the policy is intended to deal with, as well as highlighting the purpose of increasing awareness of the effects of alcohol and drug misuse, staff responsibility and the procedure to follow.
Testing may be a part of this procedure, and this is far more likely with safety-critical organisations - more than half of the safety-critical companies in the CIPD survey already did this in 2007, with another 18% planning to introduce it. However, with its Big Brother overtones, it is a sensitive issue, with other employers seeing it as too heavy-handed and others not regarding drug and alcohol misuse as a serious problem for them.
Dr Claire George, Concateno's laboratory director, says the company, which conducts 10 million tests annually in a range of workplaces, has seen an increase in the number of businesses seeking assistance. The methods depend on what is being tested for, but usually swab or blood tests are the first options, with samples identified as 'non-negative' needing further investigation and a second - most likely urine - test.
But, she stresses, testing is only one of the tools that make up an effective kit. "Testing is really a very small component of the whole policy, which should be about education, awareness and support."
"The introduction of a balanced policy that includes an Employee Assistance Programme providing support and education, as well as drug testing, has been proven to reduce the level of substance misuse in the workplace over time," she says. "Managers need to know what signs and behavioural changes to look for when an individual is in need of help, as well as the treatment options available."
Signs that an employee has a problem with alcohol include the physical: the smell of alcohol, bloodshot eyes, tremors or sleepiness; the behavioural: frequent lateness, excessive, unauthorised absences and careless work; or the emotional: strained relationships with co-workers and a short temper - especially in the mornings. Drug use is harder to spot, but signs could include erratic behaviour, such as overreacting to real or imagined criticism.
Richard Berry, HRD of the Culina Logistics Group, says workplace cause testing across all of its 2,500 employees has had a noticeable deterrent effect since its rollout in 2008, with the already low number of positive tests decreasing year on year. However, he also says that a crucial part of the policy is encouraging any employee with a problem to seek help, indicated by the three- month amnesty period that preceded its introduction to each department.
He also points out that policies often need to be modified to fit changing operational demands. "For one thing, we depended completely on an outside agency, so waiting for results meant a loss of productivity," he said at a recent Acas conference. "It was also difficult to maintain internal consistency on what constituted the circumstances under which to test." A move to oral swab rather than urine tests meant the testing could be managed in-house, while training for all managers helped to standardise the criteria.
South West Trains does pre-employment drug testing for every role, as well as testing after an accident or when a manager has cause for suspicion. The company also does weekly random testing on all safety-critical staff - drivers and engineering and maintenance personnel - which totals about 10% of staff a year. "We want to demonstrate to public and staff that we take this seriously," says Barbara Davenport, head of employee wellbeing at South West Trains. "We could test everyone, but it's about justification."
Testing is unannounced and presents logistical challenges, as the company has 4,600 staff members spread across several train crew depots, five engineering depots and about 150 customer-service sites. Because it is totally random there's nothing to stop the same location and even the same person coming up every time, but according to Davenport, there are few complaints. "Every now and again someone will say: 'But I've been tested four times in the past 12 months'," she says. "But it just shows that the system is random. And it's so well-established in the company that there are few problems."
South West Trains' drugs and alcohol policy has evolved since 1994, and it is very well established, but bringing the East Midlands Trains franchise under the company umbrella five years ago offered new challenges. East Midlands Trains had previously only undertaken drug testing with a 48-hour pre-announcement, and it took discussion with unions and training for all managers to bring the franchise on board with random testing.
"Interestingly enough, the number of positive cause testing results spiked shortly after this, mainly because managers then knew how to spot the signs," says Davenport.
Employer support is a crucial element of effective policies on drug and alcohol misuse, and covers counselling services, referral to occupational health practitioners and possibly time off for attendance at support groups such as AA. Disciplinary procedures are a last resort and largely reserved for those 'caught' in workplace testing.
"If someone comes forward to admit a problem, we would do an occupational health assessment and then refer them to the Community Drug and Alcohol Service and be guided by their recommendations," says South West Trains' Davenport.
"If they are in a safety-critical role we'd take them off their duties and if they need to attend any form of rehabilitation, we will support them until therapists or similar say they can return to their jobs. However, if they do test positive in random or cause testing, without seeking help first, it is a disciplinary matter."
The good news is that evidence suggests that a thorough approach is effective. The CIPD survey revealed that 60% of the employees whose organisations had referred them to treatment or supported them through rehabilitation continued to work for the organisation after they had successfully managed their problem.
"What is important in the workplace is for employers to be alert to non-specific ongoing changes in professional behaviour, such as absenteeism, poor timekeeping or decreased performance," concludes Addaction's Dr Agath. "Those changes could be due to a myriad of reasons - but although a broken heart needs time to heal, drug and alcohol misuse needs treatment. And the earlier the intervention, the better the outcome."