Critically assess the efficacy of treatment in changing addictive behaviour

University Degree Subjects allied to Medicine

In order to critically evaluate the efficacy of treatment in changing addictive behaviour, an analysis of several factors needs to be addressed. Within this essay key issues such as theories, models of behaviour change and the methadone programme will be summarised. Treatments such as Cognitive Behavioural Therapy, Motivational Interviewing, Motivational Enhancement Therapy and Twelve Step-Facilitation will be critically assessed before finally moving onto the concept of unassisted behaviour change and natural recovery.

Behaviour change is a complex and highly emotive subject with several competing theories as to ‘what’ and ’why’ it takes place. Many theories and models have been established in an attempt to answer these questions such as the Health Belief Model, Social Cognitive (Learning) Theory, the Theory of Reasoned Action, the Theory of Planned Behaviour and the Transtheoretical Model. Many of the theories share a number of factors such as intentions to behave, environmental constraints impeding the behaviour, skills, outcome expectancies, norms for the behaviour, self-standards, affect and self-confidence with respect to the behaviour. Efforts to change an individual’s behaviour via education and counselling must take these factors into account and address those deemed relevant to the individual and their particular need.

The Health Belief Model relates largely to the cognitive factors predisposing a person to healthy behaviour, concluding with a belief in one's self-efficacy for the behaviour. The model leaves much to be explained by factors enabling and reinforcing one's behaviour, and these factors become increasingly important when the model is used to explain and predict more complex lifestyle behaviours that are maintained over a lifetime (Becker, 1974).

The Social Cognitive Theory emphasizes the interaction between a person’s cognitions and their behaviour through cognitive constructs such as self-efficacy and outcome expectancies (or response efficacy).

Outcome expectancy refers to the expectancy that a positive outcome or consequence will occur as a function of the behaviour. Self-efficacy (or self-confidence specific to a behaviour) is a self-perception of having skills to perform the specific behaviour. The theory describes behaviour change as a three fold interaction of ‘person’, ‘behaviour’ and ‘environment’ interacting dynamically in a process called ‘reciprocal determinism’ (Bandura, 1989).

The Theory of Reasoned Action and the Theory of Planned Behaviour place relatively more emphasis on the concept of behavioural intention. The concept of behavioural intention can be predicted by the persons expectancies regarding the outcomes of a behaviour, attitudes toward the behaviour and normative beliefs the person has with respect to what influential’s would do in a specific situation. The Theory of Planned Behaviour extends beyond the original Theory of Reasoned Action to include the concept of perceived behavioural control which can influence intentions and behaviour. The addition of perceived behavioural control attempts to account for factors outside the individual’s control including the absence of resources or skills and impediments to behavioural performance. The perceived behavioural control construct is very similar to the concept of self-efficacy described by the Social Cognitive Theory however they are operationalised somewhat differently (Ajzen & Fishbein, 1980).

In the Transtheoretical Model or the Stages of Change Model the cognitive and behavioural change progresses as the individual moves through the following stages: pre-contemplation where the benefits of lifestyle change are not being considered, the contemplation stage where the individual is starting to consider change but has not yet begun to act this intention, the preparation stage where the individual is ready to change their behaviour and prepares to act, the action stage where the individual makes the initial steps towards behaviour change and finally the maintenance stage whereby the individual maintains the behaviour change whilst possibly experiencing relapses (Prochaska & DiClemente, 1983).

All of the above models can be utilised within a treatment centred environment by the individual to maximise understanding and potential for change whilst minimising potential relapse into previous negative behaviours. Treatment, however, usually implies some form of external management such as therapy, healing and more often then not medication. Although treatment will almost certainly utilise some or perhaps all of the models mentioned to some degree, medication, especially for rehabilitation of opiate users will probably play a fundamental role in the treatment. This is evident within the current methadone programmes for stabilising opiate dependant individuals.

Methadone was created by German scientists during World War II due to a shortage of morphine. Methadone is chemically unlike morphine or heroin but produces many of the same effects. It was first introduced into the United States in 1947 as an analgesic and is primarily used today for the treatment of opiate addiction. It is available in oral solutions, tablet form and injectable Schedule II formulations. Importantly, it is almost as effective when administered orally as it is by injection thus making it an ideal treatment for intravenous opiate drug users. Methadone’s effects can last up for up to 24 hours, thereby permitting once-a-day oral administration in heroin detoxification maintenance programmes. High-dose methadone can block both the physical and psychological effects of heroin, thereby discouraging its continued use by addicts. Adversely, chronic administration of methadone results in tolerance and dependence in the same way as heroin. However, the withdrawal syndrome develops more slowly and is less severe albeit more prolonged than that associated with heroin withdrawal.

Ironically, methadone used to control opiate addiction is frequently encountered on the black-market and has been associated with a number of overdose deaths ( cited 10/03/06). Methadone is the dominant therapy used for the treatment of opiate users within the USA, with over 115,000 American opiates users reliant on this treatment, and is fast becoming the prevailing treatment within Scotland. This is despite, most studies suggesting that the most important factors of behavioural change lie within the counselling that accompanies treatment (Farrell, Howes & Taylor, 1998)

Interventions based on the Theory of Planned Behaviour are of limited efficacy in changing behaviour (Hardeman, Johnston, Johnston, Bonetti, Wareham, & Kinmonth 2002). Several possible explanations have been presented in order to explain this. Primarily, targeted cognitions are confined to three types of beliefs. These being behavioural, normative and control beliefs, with these targeted cognitions being the most frequently reported as salient by a group rather than those most salient to the individual. Therefore, if the individual does not hold these beliefs in themselves this type of intervention will fail. Another intervention method under the umbrella of planned behaviour ...

This is a preview of the whole essay

The basis of CBT is empowering the individual with the skills to identify the thoughts or feelings that lead them to abuse either drugs or alcohol and to then challenge these negative thoughts. Once these negative thoughts are identified several coping mechanisms are utilised by the individual in order for them to be able to resist the urge to return to drugs or alcohol. However, as changing health behaviours is not the primary task of clinical psychologists, there has been limited research into the efficacy of these techniques in the context of behaviour change and little evidence of the efficacy of CBT in changing health behaviours. Moreover, a certain level of cognitive ability is required by the individual so CBT is therefore not suitable for those suffering from alcohol (e.g. Korsakoff’s) or drug related brain damage (Jarvis, Tebbutt, & Mattick1995)

An application of CBT is motivational interviewing. The concept of motivational interviewing evolved from experience in the treatment of problem drinkers, and was first described by Miller (1983) in an article published in Behavioural Psychotherapy. These fundamental concepts and approaches were later elaborated by Miller and Rollnick (1991) in a more detailed description of clinical procedures.

Miller and Rollnick state that Motivational interviewing is a directive; client centered counseling style for eliciting behavior change by helping clients to explore and resolve ambivalence. Compared with nondirective counseling, it is more focused and goal-directed with the examination and resolution of ambivalence as its central purpose, and the counselor is intentionally directive in pursuing this goal. Miller and Rollnick (2002) believe that it is vital to distinguish between the spirit of motivational interviewing and techniques that they have recommended to manifest that spirit. Further, they believe that clinicians and trainers who become too focused on matters of technique can lose sight of the spirit and style that are central to the approach.

The efficacy of Motivational interviewing is reviewed by Burke Burke, Arkowitz and Menchola (2003) who point out that the most widely used approach related to motivational interviewing is one in which the client (usually alcohol or drug-addicted) is given feedback based on individual results from standardized assessment measures, often the Drinker’s Check-Up (DCU; Miller, Sovereign & Krege, 1988) or a modification of it. The feedback is delivered in a motivational interviewing style and discussion of the problem may extend to one or more sessions that continue to embody the fundamental spirit and methods of motivational interviewing.

Motivational interviewing is an approach to treatment that has become extremely popular in the alcohol problems field over the last decade in many parts of the world, especially Britain. It is the most sought-after form of post-qualification training at a leading centre for training in the addictions (Leeds Addiction Unit, 1999) and is now widely used throughout the country, either as a form of treatment in its own right for clients with relatively less severe problems, or as a component of treatment for those with more severe difficulties. The principles of motivational interviewing are also consistent with recent theoretical formulations of the nature of the addictive process (Orford, 2000).

Motivational Enhancement Therapy is based on the principles of motivational interviewing (Miller & Rollnick, 1991), but includes feedback to the client of the results of assessments carried out prior to the first session of MET, as used in a form of brief intervention known as the Drinker's Check-up (Miller et al., 1988). The brevity and relatively low cost of MET is also fully in accord with the recent interest in brief interventions in the UK alcohol treatment field. In an influential health care bulletin, Freemantle, Gill, Godfrey, Long, Richards, Sheldon, Song and Webb (1993) concluded that evidence from clinical trials suggests that brief interventions (for alcohol problems) are as effective as more expensive specialist treatments.

In a situation of limited resources for healthcare provision and the increasing advocacy of briefer approaches to alcohol problems treatment, many purchasers of alcohol services are seeking to lower the costs of treatment in this service area. While some authors have warned that the available evidence did not justify the application of brief interventions to those with more severe problems (Chick, 1999; Heather, 1995). MATCH findings provide strong support for the hypothesis that briefer treatments, at least of the kind represented by MET, can be as effective as more intensive treatments among clients seen by alcohol specialist services. This integrated MET approach was delineated in a detailed therapist manual (Miller, Zweben, DiClemente, & Rychtarik, 1992) developed for Project MATCH, a multi-site trial of alcoholism treatments funded as a cooperative agreement by the National Institute on Alcohol Abuse and Alcoholism (NIAAA; Project MATCH Research Group, 1993).

The ‘Twelve Step-Facilitation Therapy’ has its roots in the Minnesota Model first described by Daniel J. Anderson in the early 1930’s and as implemented in most AA-oriented treatment programmes (e.g., the Hazelden Foundation, the Betty Ford Foundation, the Sierra Tucson Centre, and others).

These models assume addiction can be arrested but not cured, subscribe to the AA/NA philosophy, as described in AA/NA literature, that relies heavily on a combination of spirituality and pragmatism, and advocate peer support as the primary means for achieving sustained sobriety. Any approach that advocates controlled use of alcohol or other drugs (as compared with abstinence) is fundamentally dissimilar to Twelve Step-Facilitation with respect to basic treatment goals.

Cognitive-behavioral approaches that are based on the idea that problem drinking and other drug abuse stems primarily from inadequate stress management skills and that aim to enhance problem solving and coping skills differ from TSF with respect to the assumption of peer support as fundamental to recovery. Twelve Step-Facilitation therapies also assume that alcoholism and other drug addictions are primary diagnoses and not symptoms of another diagnosis (e.g. depression, antisocial personality).

Research investigating the effectiveness of AA and other Twelve-step group has been reported as inconclusive (Hopson, 1996) and opinion for some time has been mixed. It has been claimed that Twelve-Step methodology has not been effectively researched and that there is little independent objective evidence to support its effectiveness (Georgakis & Shepard, 1998). McCrady and Miller (1993) reviewed studies of the effectiveness of AA and found only two methodologically sound studies, neither of which indicated that AA was more effective than alternative treatments. The difficulty in being able to conduct research into the effectiveness of AA or other Twelve-Step programmes with scientific rigour may be in part due to difficulty in obtaining hard data. A further criticism includes the large percentage of alcoholics who drop out of AA (Galaif & Sussman, 1995).

A further difficulty involves the accessibility of the groups themselves as they are closed i.e. the groups are anonymous and do not allow non member entry. In spite of methodological problems aggravated by the anonymous, voluntary, self-selection of AA membership, it is also claimed that there is evidence which indicates that AA is a very useful approach for alcoholics.

Chappel (1993) states that there is evidence which suggests that many alcoholics who become involved in AA find something they can use to improve their lives on a long-term basis. Emricks’s (1987) review of survey and outcome evaluations of AA alone or AA as an adjunct to professional treatment indicated that 40- 50 percent of alcoholics who maintain longer, active membership in AA have several years of total abstinence while involved, 60-68 percent improve, drinking less or not at all during AA participation..

It is argued that treatment is not necessarily the only answer for recovery since the concept of unassisted behaviour change or natural recovery has came to light. However, the concept of natural recovery remains heavily debated. Since the mid 1970’s a growing number of studies on recovery from substance use problems without professional help have been published (Valliant 1982; Klingemann 1991; Sobell, Sobell & Tonneatto 1992; Tucker & Gladsjo 1993; Bischof et al 2000; Bischof et al 2001).

Historically, research on natural recovery focused on proving natural recovery to be a genuine phenomenon. Early research usually argued from a descriptive level without taking control groups into consideration (Tuchfield 1981 & Stall 1983). In the early 1990’s a second wave of research began to focus on differences between treated and untreated recoverers (Klingemann 1991; Sobell et al 1992; Tucker & Gladsjo 1993 & Blomquist 1999). However, most findings revealed only small differences between treated and untreated subjects. Although empirical evidence is still scarce the main topics in the literature on natural recovery are concepts such as social capital (Granfield & Cloud, 1996) and the severity of alcohol related problems (Cunningham 1999; Kingemann et al 2001). These resources are viewed as crucial for successful unassisted recoveries. Only one study revealed a substantial impact of problem severity on help-seeking and of social resources on natural recovery (Blomquist, 1999), however, these findings are restricted due to small sample sizes.

Concepts such as problem severity and social resources may interact reciprocally e.g. when problems are small, less social capital is necessary to overcome an addictive disorder without treatment, while in the more severe cases social capital might be a necessary prerequisite for recovery without specific treatment. Therefore a lack of empirical evidence for concepts such as social capital in natural recovery might be due to the compensation of different factors in heterogeneous populations.

Early studies on natural recovery based on qualitative data emphasised the varied nature of unassisted pathways of out addiction. For example, Klingmann’s 1991 groundbreaking study on natural recovery described a typology of motivation to stop on the grounds of qualitative data. This at first glance appears to go completely against bio-medical approaches such as the concept forwarded by Alcoholics Anonymous (AA), which is one based on a disease model of addiction. This model emphasises both the powerlessness of the individual and the progressive nature of the ‘disease’ implying an almost impossibility for any addicted individual to break the cycle of addiction without help from trained professionals and practitioners or self-help groups. The key transitionary stage for recovery is when the addict reaches the stage were he is, ‘hitting bottom’ which is characterised by physical, interactional and psychological collapse. This philosophy is also forwarded Schuckit (1998) the DSM IV and ICD 10 manuals. However, ‘hitting bottom’ may also be put into differing perspectives such as the group characterised by Klingemann as ‘cross-road types’, who act on the basis of a single crisis (such as health or psychological problems);

Secondly, a group which consists of ‘pressure-sensitive types’, who react positively to social pressure will then force them to choose between a life of conformity and a career of addiction. In contrast to this group, which can usually define a specific turning point, another group was characterised as slowly and harmoniously drifting out of addiction. Their motivation to quit is based on positive changes in their social environment.

Another group was described as having had esoteric or religious experiences as turning points. However, Klingemann’s typology is based on qualitative data from interviews of the limited number of 60 former addicts, of whom 30 were formerly alcohol dependent and 30 were formerly heroin-dependent. Broadly, the types generated by Klingemann differ on at least two dimensions: problem severity (including social pressure) and resources (social capital). Both of these dimensions could be viewed as systematic.

Most of the natural recovery studies with alcohol and drug abusers have shown methodologically weak. The majority of studies do not adequately describe respondents in terms of their demographic or substance use history backgrounds and features of their recoveries. Research in this area would be strengthened and also our understanding of natural recoveries by considering respondents’ demographic characteristics at the time of their recovery. Such information is useful in identifying variables common among naturally recovered substance abusers. Studies also need to obtain detailed descriptions of respondents’ pre-recovery substance abuse history in order to provide a clear picture of the pattern and severity of respondent’s substance use.

Drug and alcohol misuse treatments can be effective in reducing problem behaviours. This is shown by studies conducted over the past three decades. These studies have compared treatment to no treatment (or minimal treatment), and pre-treatment to post-treatment problem behaviours. Studies showing the effectiveness of drug misuse treatments have been conducted with clients with different types of drug problems, different treatment interventions, and in different treatment settings (Sorensen & Copeland, 2000; Hser, Evans & Huang, 2005)A comprehensive and detailed review concluded that drug misuse treatment is effective in terms of reduced substance use; improvements in personal health and social functioning; and reduced public health and safety risks (McLellan, Wood, Metzger, McKay & Alterman, 1997).

Although there are areas of treatment where evidence is available to guide decisions about treatment provision, in other areas the available research evidence is insufficiently strong for this and in yet other (often important) areas of treatment, research evidence is lacking. In the absence of research evidence, decisions about the provision of treatment must be made according to criteria other than those of empirical research. A principal aim of substance misuse treatment research is to provide evidence to improve the effectiveness of treatments for problem substance users. Relevant evidence that can be used to improve treatment and patient outcomes requires more than studies of efficacy for specific procedures. The therapeutic process consists of more than just a clinical intervention. Evidence is also required about the nature and severity of client problems, about the processes which occur during treatment, about the role of staff competence and skills, and about the organisation and provision of services. However, it must be kept in mind that no two addicts are the same and one form of treatment may work for one and not the other. Therefore whatever treatment works for a particular individual in the road to recovery and sobriety is a successful one.

References

Ajzen, I. & Fishbein, M. (1980), Understanding Attitudes and Predicting Social Behaviour, Englewood Cliffs, NJ: Prentice-Hall, Inc.

American Psychiatric Association (1995). Diagnostic and Statistical Manual of Mental Disorders, 4th Ed International version. Washington, DC: American Psychiatric Association.

Bandura, A. (1989). “Human agency in Social Cognitive Theory”. American Psychologist, 44, 1175-1184

Beck, A. T. (1963). “Thinking and depression”. Archives of General Psychiatry, 9, 324–333.

Becker, M. H. (Ed.). (1974). The Health Belief Model and Personal health Behaviour. Thorofare, NJ: Charles B. Slack.

Bischof, G., Rumpf, H. J., Hapke, U., Meyer, C. & John, U. (2000). “Maintenance factors of recovery from alcohol dependence in treated and untreated individuals”. Alcoholism: Clinical and Experimental Research, 24, 1773–1777.

Bischof, G., Rumpf, H. J., Hapke, U., Meyer, C. & John, U. (2001). “Factors influencing remission without formal help from alcohol dependence in a representative population sample”. Addiction, 96, 1327–1336.

Blomquist, J. (1999). “Treated and untreated recovery from alcohol misuse: environmental influences and perceived reasons for change”. Substance Use and Misuse, 34, 1371–1406.

Burke B. L., Arkowitz. H & Menchola. M. (2003). “The efficacy of motivational interviewing: A meta-analysis of controlled clinical trials”. Journal of Consulting and Clinical Psychology, 71, 843–861.

Chick, J. (1999) “Alcohol dependence, anxiety and mood disorders”. Current Opinion in Psychiatry, 12, 297–301.

Cunningham, J. A. (1999) “Resolving alcohol-related problems with and without treatment: the effects of different problem criteria”. Journal of Studies on Alcohol, 60, 463–466.

Ellis, A. (1962). Reason and emotion in psychotherapy. Secaucus, NJ: Lyle Stuart.

Emrick C D (1987). Alcoholics Anonymous and other Twelve- Step groups. In M Galanter & H D Kleber (Eds.), The American Psychiatric Press Textbook of Substance Abuse Treatment (2nd Ed.) (pp. 403-412). Washington, D.C.: American Psychiatric Press, Inc.

Farrell, M., Howes, S., Taylor, C.(1998) “Substance misuse and psychiatric comorbidity: an overview of the OPCS National Psychiatric Morbidity Survey”. Addictive

Behaviours, 23, 909–918.

Freemantle, N., Gill, P., Godfrey, C., Long, A., Richards, C., Sheldon, T., Song, F. and Webb, J. (1993) “Brief Interventions and Alcohol Use”. , Effective Health Care Bulletin #7. Nuffield Institute for Health, Leeds.

Galaif, E. R., & Sussman, S. (1995). “For whom does alcoholics anonymous work”? The International Journal of the Addictions, 30(2), 161-184.

Granfield, R. & Cloud, W. (1996) “The elephant that no one sees: natural recovery among middle-class addicts”. Journal of Drug Issues, 26, 45–61.

Hardeman, W., Johnston, M., Johnston, D. W., Bonetti, D., Wareham, N., & Kinmonth, A. L. (2002). “Application of the theory of planned behaviour in behaviour change interventions: A systematic review”. Psychology and Health, 17, 123–158.

Heather, N. (1995). “Treatment Approaches to Alcohol Problems”. World Health Organization Regional Publications: European Series 65. WHO Regional Office for Europe, Copenhagen.

Hopson, R. E., & Moses, M. J. (1996). “Theology of paradox: A Pauline contribution to the understanding and treatment of addictions”. Journal of Ministry in Addiction and Recovery, 3(1), 7-15.

Hser, Y. I, Evans, E & Huang, Y.C (2005). “Treatment outcomes among women and men methamphetamine abusers in California”. Journal of Substance Abuse Treatment, 28, 77-85.

Jarvis, T.J., Tebbutt, J. & Mattick, R.P. (1995) . Chichester, John Wiley.

Johnson, P.N., and Chappel, J.N., 1994. “Using AA and other 12-step programs more effectively”. Journal of Substance Abuse Treatment 11(2):37-142.

Klingemann, H. K. (1991) “The motivation for change from problem alcohol and heroin use”. British Journal of Addiction, 86, 727–744.

Klingemann, H., Sobell, L., Barker, J., Blomquist, J., Cloud, W., Ellinstead, T., Finfgeld, D., Granfield, R., Hodgings, D., Hunt, G., Junker, C., Moggi, F., Peele, S., Smart, R., Sobell, M. & Tucker, J. (2001) Promoting self-change from problem substance use: practical implications for policy, prevention and treatment. Dordrecht: Kluwer Academic Publishers.

Mahoney, M. J. (1974). Cognitive and behaviour modification. Cambridge, MA: Ballinger.

McCrady, B.S. & Miller, W.R. (1993). Research on Alcoholics Anonymous: Opportunities and Alternatives. New Brunswick, New Jersey: Rutgers University Press.

McLellan AT, Wood GE, Metzger DS, McKay J, Alterman AI (1997). Evaluating the effectiveness of addiction treatments: reasonable expectations, appropriate comparisons. In: J.A, Egerton, D.M. Fox, A.I. Leshner (Eds). Treating Drug Abusers Effectively. Oxford: Blackwell.

Meichenbaum, D. H. (1977). Cognitive-behaviour modification: An integrative approach. New York: Plenum Press.

Miller, W. R. (1983). “Motivational interviewing with problem drinkers”. Behavioural Psychotherapy, 11, 147-172.

Miller, W. R., Zweben, A., DiClemente, C. C., & Rychtarik, R. G. (1992). Motivational Enhancement Therapy manual: A clinical research guide for therapists treating individuals with alcohol abuse and dependence. Rockville, MD: National Institute on Alcohol Abuse and Alcoholism.

Miller, W. R., Sovereign, R. G., & Krege, B. (1988). “Motivational interviewing with problem drinkers: II. The Drinker's Check-up as a preventive intervention”. Behavioural Psychotherapy, 16, 251- 268.

Miller, W. R. & Rollnick, S. (1991) Motivational Interviewing. New York: Guilford Press.

Miller, W. R., & Rollnick, S. (2002). Motivational interviewing: Preparing people for change. New York: Guilford Press.

Orford J. (2001a) Excessive Appetites: A Psychological View of Addictions, 2nd edn.Chichester: Wiley.

Prochaska, J. O., & DiClemente, C. C. (1983). “Stages and processes of self-change of smoking: Toward an integrative model of change”. Journal of Consulting and Clinical Psychology, 51, 390-395.

Rumpf, H.-J., Meyer, C., Hapke, U., Bischof, G. & John, U. (2000) “Utilization of professional help of individuals with alcohol dependence or abuse: findings from the TACOS population study”. Sucht, 46, 9–17.

, M.A., (1998). “Biological, psychological, and environmental predictors of the alcoholism risk: A longitudinal study”. Journal of Studies on Alcohol 59, 485–494

Sobell, L. C., Cunningham, J. A., Sobell, M. & B. (1996) “Recovery from alcohol problems with and without treatment: prevalence in two population surveys”. American Journal of Public Health, 7, 966–972.

Sobell, L. C., Sobell, M. B. & Toneatto, T. (1992) Recovery from alcohol problems without treatment. In: Greeley, J., ed. Self Control and the Addictive Behaviours,. New York: Macmillan Publishing.

Sorensen, J. L & Copeland, A. L (2000). “Drug abuse treatment as an HIV prevention strategy: a review”. Drug Alcohol Dependence, 59, 17-31.

Stall, R. (1983) “An examination of spontaneous remission from problem drinking in the bluegrass region of Kentucky”. Journal of Drug Issues, 13, 191–206.

Tuchfeld, B. S. (1981) “Spontaneous remission in alcoholics: empirical observations and theoretical implications”. Journal of Studies on Alcohol, 42, 626–641.

Tucker, J. A. & Gladsjo, J. A. (1993) “Help-seeking and recovery by problem drinkers: characteristics of drinkers who attended Alcoholics Anonymous or formal treatment or who recovered without treatment”. Addictive Behaviours, 18, 529–542.

Vaillant, G. E. (1982) “Natural history of male alcoholism IV: paths to recovery”. Archives of General Psychiatry, 39, 127–133.