• alcohol;
  • illicit drugs;
  • mindfulness;
  • polydrug use;
  • relapse;
  • treatment outcomes

The systematic review by Staiger and colleagues [1] casts the spotlight on alcohol use as a potential impediment to recovery from illicit drug dependence. They argue, justifiably, that treatment outcome research needs to place greater emphasis on assessing the extent of alcohol use to establish whether drug substitution is occurring and to determine whether alcohol use increases the risk of relapse to primary drug use. The question of whether treatment services are giving enough specific attention to alcohol use is also raised.

One of the many challenges facing treatment outcome research is how best to measure treatment success or failure given the complexity of drug dependence. It is well recognized that drug dependence is often a chronic relapsing condition, associated with polydrug use, comorbid psychopathology, physical health problems, poorer social functioning, high levels of unemployment and legal problems. How, then, do researchers determine what to assess and what to forgo in balancing the need for information about treatment outcomes, with the burden placed on study participants?

A common method for outcome studies to streamline the information collected is to classify participants according to the primary drug for which they are seeking treatment. This approach has appeal, as drug classes differ in their neurophysiological and psychological effects, and framing studies of illicit drug use in this way aids the interpretation of analyses based on drug use typologies [2]. Unfortunately, as found by Staiger et al., the data reported about other drug use are often fairly limited, making the impact of specific patterns of polydrug use on treatment outcome hard to determine.

Reassuringly, a recent analysis of 10-year trajectories for heroin, cocaine and methamphetamine users demonstrates that group descriptions do appear to present valid information about drug use patterns [2]. Using growth modelling, the study found declining primary drug levels for heroin and methamphetamine users and fairly consistent levels over 10 years for cocaine users. Non-primary drug use remained at consistently low levels or reduced in parallel with the primary drug. The study lends support to the validity of longitudinal analyses based on primary drug classifications but, as the authors suggest, a focus on individuals who deviate from the general patterns may be beneficial in identifying strategies for prevention or intervention.

There are many reasons why alcohol use warrants more detailed attention, both from a research and treatment perspective. First, alcohol's legal status and common usage in most western societies may cause illicit drug users to underestimate the risks associated with alcohol use. This is certainly implied by the high levels of alcohol use seen among treatment entrants [3, 4]. Alcohol use is also strongly associated with an increased risk of fatal and non-fatal heroin overdose [5], suicide [6] and motor vehicle accidents [7]. Given the high rates of hepatitis B and C seen among injecting drug users, alcohol use is also problematic in that it exacerbates the progression of liver disease [8]. Illicit drug users who use alcohol are also more likely to be victims of physical violence [9]. Indeed, the harms associated with alcohol use among illicit drug users are so pervasive it could be argued that drug users should be educated about these, irrespective of their current alcohol use patterns.

In attempting to address the question of whether or not alcohol use post-treatment leads to relapse to illicit drug use, Staiger and colleagues [1] give no consideration to the psychiatric comorbidity that could be driving this drug use behaviour. This would clearly need to be explored in future studies attempting to understand the mechanisms involved in alcohol use triggering relapse to illicit drug use.

The complex nature of drug dependence, with its high levels of polydrug use and psychiatric comorbidity, is a challenge to treatment providers and researchers world-wide. The use of relapse prevention strategies, tailored for the individual to reduce the likelihood and severity of relapse, has been an important cornerstone of drug treatment for decades [10]. Research that improves our understanding of the processes involved in relapse is to be encouraged. An interesting development in recent times has been the introduction of mindfulness-based relapse prevention. Mindfulness is a trans-diagnostic approach that may be very well suited to illicit drug users, given their high levels of comorbidity. In addition to improving the focus on alcohol use, perhaps future treatment outcome studies should assess factors such as distress tolerance and emotion regulation skills, which cut across diagnostic boundaries and have implications for treatment.

Declaration of interests



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