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The Effect of Twelve Step Self-Help Group Attendance on One Year Post Treatment Abstinence and Quality of Life in Recovering Substance Abusers
It is important to research the factors influencing the recovery of those suffering from substance abuse. In the United States, the use of the twelve step program is widespread. Research suggests the twelve step program could function also as a tool for aftercare in the Netherlands.178 ex-clients from an addiction clinic performed surveys at two separate times, both written and by phone. A MANOVA was performed to see if the attendance at twelve step meetings had an effect on abstinence and quality of life. An effect on abstinence was found. No effect was found on the difference in QOL.
The Effect of Twelve Step Self-Help Group Attendance on One Year Post Treatment Abstinence and Quality of Life in Recovering Substance Abusers
Drug abuse is a very common problem in the world. In 2013 it was estimated that some 27 million people worldwide are suffering from drug use disorders or drug dependence (United Nations Office of Drugs and Crime, 2015). Of those 27 million, only about 4.5 million find treatment. Research suggests that drug use disorders and drug dependence should be viewed as a chronic condition, developed as a result of a complex multifactorial interaction between repeated exposure to drugs and biological and environmental factors (Dennis & Scott, 2007). Consequently, the health care costs of individuals with drug use disorders are nearly twice as high as those of individuals without drug use disorders, thereby contributing to the growing costs of health care (Boyd et al, 2005). As such, it is important to continue to research different factors that influence the recovery of individuals with drug use disorders, even after they have completed treatment. Gaining understanding in the recovery process may help to find means to reduce the costs of health care on society.
Most research on treatment methods for substance abuse was done in the United States of America. In the US the twelve step principles from Alcoholics Anonymous (AA) have been increasingly incorporated in treatment (Corveleyn & Van Limbergen, 2001). It is estimated that the AA alone has over 1.2 million members in the US and over 2 million worldwide (“Estimates of A.A. Groups and Members”, 2015). The aim of the twelve step model is to provide a change of lifestyle, focused on abstinence and the helping of others with alcohol or drug related problems (Wilson, 2015). Originally the steps were designed for alcoholism only. Later however, the same principles were applied to other substances and even several behavioral addictions, such as gambling or Sex and Love Addiction (e.g., [Homepage for Sex and Love Addicts Anonymous], n.d.). It provides a structure in the form of meetings of self-help groups that give substance abusers both a place and an organization to continually work on their recovery and that of others. Theoretically it could therefore function as a continuous means of maintaining abstinence.
Integration of the twelve steps with treatment has led to the development of what is known as Twelve Step Facilitation Therapy (TSF) (Kingree, 2013). An example of a TSF method is the Minnesota Model (Cook, 1988). The Minnesota Model aims to be more multidimensional in its approach to treat addiction, combining CBT (Cognitive Behavioral Therapy) by a trained psychologist with the practical, real life experience of recovering substance abusers and the twelve steps (Corveleyn & Van Limbergen, 2001). It is currently the most widely used clinical treatment method for substance abuse in the US and the UK, and is growing in European countries like Ireland, France, Switzerland and Sweden (Corveleyn & Van Limbergen, 2001). Research suggests that TSF proved about equally as effective as both CBT and MET (Motivational Enhancement Therapy) for treating alcoholism (Group, 1998).
Research in the US suggests that involvement in twelve step self-help groups can be a valuable addition to regular addiction treatment in maintaining abstinence (Montgomery, Miller & Tonigan, 1995; Fiorentine & Hillhouse, 2000; Kingree & Thompson, 2011; Witbrodt, Mertens & Kaskutas et al., 2012). It was found that subjects who took part both in treatment and in twelve step self-help groups had significantly higher rates of abstinence than subjects who partook in either treatment or twelve step self-help groups (Fiorentine & Hillhouse, 2000). In a more longitudinal study it was found that greater twelve step self-help group attendance lead to higher abstinence rates five and seven years after treatment (Witbrodt, Mertens & Kaskutas et al., 2012). Some studies did not find an effect of twelve step self-help group attendance on abstinence. However they did find that greater involvement in twelve step self-help groups (i.e., feeling a member of the group and having a sponsor) resulted in a greater probability of abstinence after six months, for alcohol (Montgomery, Miller & Tonigan,1995) and both alcohol and illicit drugs (Kingree & Thompson, 2011). Given the above research, many addiction specialists advocate twelve step self-help group involvement as a post treatment aftercare activity that is essential to long term abstinence (Troyer, Acampora, O’Connor & Berry, 1995; Morgenstern, Kahler, Frey & Labouvie, 1996).
In 2013 an estimate of 80.000 people applied for addiction care in the Netherlands, where the substance was either a primary or secondary problem (Van Laar, Van Ooyen-Houben, Meijer et al., 2013). Substances abused were alcohol (an estimated 34.000), cannabis (an estimated 15.000), cocaine (an estimated 14.000), opiates (an estimated 12.000), ecstasy and amphetamines (an estimated 2.500), sedatives and tranquilizers (an estimated 1.500) and GHB (an estimated 900). Between 2% (Opiates) and 34% (Cannabis) of the recipients of treatment were considered first time applicants for addiction care. Compared to the weighted average for members of the European Union, one year prevalence numbers in the Netherlands are ‘Low’ for opiates, ‘Average’ for cannabis and amphetamines, ‘Above average’ for cocaine and ecstasy and ‘unknown’ for GHB and tranquilizers (Van Laar, Van Ooyen-Houben, Meijer et al., 2013)
Currently, treatment of substance abuse is largely based on CBT and MET in the Netherlands (Van den Brink, 2005).In the Netherlands, twelve step self-help groups like the AA or NA are a lot less widespread than in the United States. About 5000 to 6000 people attend twelve step meetings regularly in the Netherlands (Geelen, 2003). This number includes members of specific twelve step meetings designed for relatives and/ or life partners of substance abusers. Most attendees of these meetings attend weekly for multiple years and the twelve step model becomes a part of their life (Geelen, 2003). The fact that the twelve step model becomes a part of their life further suggests that it can function as a means of maintaining abstinence after treatment. No research has been conducted to verify if the results found in the United States translate to the population of the Netherlands.
The World Health Organization (2014) gives the following definition of Health:” Health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity” (Page 1). It therefore follows that the quality of one’s life can and should be described in terms of both the absence of negatives as well as the presence of positives. It follows that abstinence – the absence of the abused substance and therefore the absence of negative effects of the abuse – should not be the only goal for treatment. Of equal importance should be the improvement of quality of life. There has been little research into the relationship between abstinence and quality of life. One way of looking at it can be to compare the quality of life for active substance abusers with the quality of life for recovering substance abusers.
Active substance abusers by definition can be seen as having no abstinence. What little empirical evidence exists suggests that for active substance abusers the overall quality of life is low and the level of stress is high (Laudet, Morgan & White, 2006). Some see alcohol and drug use as a form of self-medication for existential pain, suggesting substance abusers suffer from considerable stress (Ventegodt, Merrick, & Andersen, 2003). Alcohol and drug abuse can have negative consequences on many levels of life, including physical and mental health, financial situation, living situation (i.e., potentially cause homelessness) and social situation (i.e., leading to estrangement from family and friends) (Laudet, Morgan & White, 2006). To underscore the gravity of the impact of substance abuse on one’s life, one study found the quality of life was significantly lower for clients receiving addiction treatment, compared to patients awaiting cardiac surgery (Smith & Larson, 2003).
Recovering substance abusers can be seen as having high levels of abstinence. Very little research has been done to see what the effect is of these high levels of abstinence on quality of life (White, 2004). Research found that the amount of stress decreased and quality of life increased over time for recovering substance abusers, the longer they remained abstinent (Laudet, Morgan & White, 2006). For recovering substance abusers stress is considered an important trigger for relapse, suggesting that the stress levels for successful recovering substance abusers decrease over time (Titus, Dennis, White, Godley, Tims & Diamond, 2002). Areas considered important to recovering alcohol and drug abusers for quality of life were ‘social support’, ‘spirituality, religiousness and life meaning’ and ‘affiliation with twelve step fellowships’ (Laudet, Morgan & White, 2006).
The differences between active substance abusers and recovering substance abusers seem to suggest there is a relationship between abstinence and quality of life. It follows therefore that it is important to look at both abstinence and quality of life when researching the factors influencing recovery from substance abuse.
This study aims to research the possible effect of twelve step self-help group attendance on post treatment abstinence and quality of life in the Netherlands. Quality of life can be viewed from three perspectives: quality of life defined as the quality of one’s life conditions, quality of life defined as one’s satisfaction with life conditions and a combination of both (Borthwick-Duffy, 1992). It was suggested that it would be best to use the combination of an objective assessment of one’s life conditions combined with the subjective satisfaction of one’s life conditions (Felce & Perry, 1995). The time and resources available for the present study was insufficient to verify the actual life conditions of the participants. Therefore, only the subjective satisfaction of the participants life conditions was taken as a measure for quality of life. It is expected that people who will report higher rates of abstinence will also report a higher level of life satisfaction. Higher levels of pre-treatment life satisfaction are expected to be related to higher levels of post-treatment life satisfaction. Based on the research from the US it is expected that higher post treatment attendance of the twelve step self-help groups would be related to higher levels of abstinence and higher levels of life satisfaction approximately one year after treatment. Therefore it is expected that people who attend twelve step self-help groups more frequently after finishing treatment will have a higher rate of abstinence, as well as a higher level of life satisfaction. From these results it would follow that twelve step self-help groups could indeed function as a cost effective aid to maintaining abstinence and improving life satisfaction after treatment. It would mean that integrating the twelve step self-help program and psychological treatment could help achieve higher rates of abstinence and an increase in overall quality of life, thereby reducing both the individual strain and public cost of recovering from substance abuse.
The population consisted of 220 clients who completed treatment at Trubendorffer for substance abuse as a primary DSM-IV diagnosis. Behavioral addiction diagnoses were excluded from the study, as levels of abstinence were too complicated to determine. The list of participants was randomized before calling started. Due to time restraints, 178 of 220 clients were called, 66 could successfully be reached to conduct the phone interview (responsrate 37.1%). The other 112 clients could not be reached, had changed their phone number, or were unable or unwilling to participate. All participants completed their treatment approximately 12 months prior to this research (M = 12.89; SD = 2.68). The sample had a mean age of 38.59 years (SD = 10.54), 63.6 % of the participants was male. 45.5 % had alcohol as their problem substance, 27.3 % cocaine, 19.7 % cannabis and 7.6 % metamphetamine. GHB and opioids are not being treated at Trubendorffer as they require a clinical detox, so they are automatically excluded from the sample.
To measure abstinence, section 1 of the Measurements in the Addictions for Triage and Evaluation was used (Schippers, Broekman, Bucholz & Rutten, 2009). It charts the use of the problematic substance over the past 30 days. The score is the amount of days out of 30 that the subject used the problematic substance. To arrive at the current ‘abstinence’ score, the participants score was subtracted from 30, thereby effectively reversing it. As it is a simple self-report question over the past month, no validity or reliability scores are available for only section 1 of the MATE.
To assess the quality of life, overall satisfaction with different areas of life was measured using the Manchester Short Assessment of Quality of Life-12 (Priebe, Huxley, Knight & Evans, 1999), measured on a seven-point Likert Scale ranging from 1 = “couldn’t be worse” to 7 = “couldn’t be better”. The MANSA-12 was compared favorably to the LQLP, showing a concurrent validity, as well as a face and construct validity and sufficient reliability (Cronbachs Alpha = .74) (Priebe, Huxley, Knight & Evans, 1999). Reliability in the current study was high (Cronbachs Alpha = .83). To arrive at the total score, the sum of all scores was taken.
To measure twelve step self-help groups attendance a question was added to the questionnaire: “In estimation, how often have you visited the twelve step self-help groups from the end of your treatment until today?” Participants answered the question on a 7-point Likert scale: 1 = never, 2 = sparingly, 3 = less than once per month, but regularly 4 = once per month, 5 = more than once per month, but less than once per week, 6 = weekly, 7 = more than once per week.
All participants upon completing Trubendorffer’s treatment program (T1) digitally completed the MATE-1 and MANSA-12. Approximately one year after treatment (T2) the questionnaires were again completed, this time via telephone. In addition, twelve step self-help groups attendance was assessed. The participants were called by phone and asked if they had time for a brief interview (5 – 10 mins). In case a participant could not be reached, a maximum of three attempts was made to contact the participant. In case the participant was unable to take the interview at that particular time, the interview was rescheduled. Participation was voluntary at all times.
To estimate the effect of overall post treatment attendance on both abstinence and the change in life satisfaction from T1 to T2, first a differential score ‘Δ life satisfaction’ was calculated. Then a MANOVA was performed, with abstinence at T2 and Δ life satisfaction as the dependent variables and overall post-treatment attendance as the independent variable. The two dependent variables will be entered simultaneously, meaning both will control for the other. Having both control for each other makes the analysis more robust.
In table 1, the minimums, maximums, means and standard deviations can be found for age, time between T1 and T2, overall post-treatment attendance, abstinence and both pre-treatment and post-treatment scores of life satisfaction. As for twelve step self-help group involvement, it was found that relatively few participants continued visiting the twelve step self-help groups after treatment. Of the 66 participants, 26 reported never again having visited a self-help group (39.4%), 15 reported having gone sparingly (22.7%). 10 reported to have gone between once a month and once a week (15,2%) and 12 reported to have gone weekly or more frequently (18,2%).
Table 1: descriptive statistics
|Time between T1 and T2||66||5||17||12.9||2.7|
|Overall post-treatment twelve step self-help group attendance||66||1||7||2.9||2.2|
|Life satisfaction T1||53||40||77||60.9||9.3|
|Life satisfaction T2||66||33||84||63.9||9.8|
|Δ life satisfaction||53||-18||26||3.3||9.9|
Most of the respondents reported to have been completely abstinent over the 30 days prior to T2 (48 for 72,7%). The remaining 18 respondents reported abstinence between 0 and 29 out of 30 days. 13 participants had failed to digitally fill out the MATE-1 and MANSA-12, therefore their Life satisfaction T1 score had to be excluded from the analysis.
Table 2: correlations
|Overall post-treatment attendance ||1|
|Life satisfaction T1 ||-.17||.14||1|
|Life satisfaction T2 ||-.12||.16||.50**||1|
|Δ life satisfaction ||-.03||.03||-.41**||-.37**||1|
*significant at the ,05 level (two-tailed)
**significant at the ,01 level (two-tailed)
Participants with a higher twelve step self-help group attendance rate between completion of their treatment and T2 were found to have a higher rate of abstinence at T2. Participants who reported higher rates of abstinence at T1 were also more likely to have higher rates of abstinence at T2. The same relationship was found between life satisfaction scores at T1 and T2: participants with a higher reported life satisfaction at T1 also reported a higher life satisfaction at T2. Participants with higher rates of twelve step self-help group attendance did not report higher life satisfaction scores at T2, nor did their Δ life satisfaction scores increase (see table 2: correlations).
Table 3: MANOVA
|Dependent variable||parameter||Β||St. Error||T||Sig||Lower bound||Upper bound||Partial η2|
|Δ life satisfaction||Overall post-treatment attendance||-.12||.67||-.18||.859||-1.471||1.231||.001|
|Abstinence||Overall post-treatment attendance||1.00||.46||2.20||.033||.086||1.914||.086|
Controlled for Δ life satisfaction, a significant effect was found of overall post-treatment attendance on abstinence at T2 (β = 1.00, t = .46, p = .033). No significant effect of overall post-treatment attendance on Δ life satisfaction was found, controlled for abstinence (β = -.12, t = -.18, p = .859). Confidence intervals and estimated effect sizes can be found in table 3. Following Cohen’s (1988) guidelines, the effect of overall post-treatment attendance on abstinence can be considered a medium sized effect.
In the current study the goal was to see if the twelve step self-help groups could function as an effective method for post treatment aftercare. In the Trubendorffer treatment program, clients are encouraged to attend the twelve step self-help groups, so they will have a network of fellow recovering abusers in place to provide support after the treatment program is completed. The support of the network would allow them to remain abstinent, even during hard times. This would then result in higher overall quality of life for the recovering substance abuser. Additionally, the fact that the recovery process would be more sustainable should reduce treatment costs in the long run, thereby greatly benefitting the society as a whole.
It was found that participants who attended twelve step self-help groups more frequently after the completion of their therapy indeed reported higher levels of abstinence than participants who attended the twelve step self-help groups less frequently. This is in line with previous research, which found that simultaneous involvement in both traditional treatment as well as the twelve step self-help groups and continued participation in the twelve step self-help groups is essential in maintaining long term abstinence. Also, Witbrodt, Mertens & Kaskutas et al. (2012) used latent class growth analysis to find that participants with high pre-treatment past 30-day alcohol severity and high subsequent twelve step self-help group attendance reported the highest abstinence rates 1, 5, 7 and 9 years after treatment. Some research however found a relationship between involvement with the twelve step self-help groups and abstinence, rather than attendance at the twelve step self-help groups and abstinence (Montgomery, Miller & Tonigan,1995; Kingree & Thompson, 2011). Both findings still support the theory that staying active in the twelve step self-help community can function as an aid to maintaining abstinence for recovering substance abusers.
The twelve step program is relatively unknown in the Netherlands. Compared to the United states, few substance abusers use it as a recovery tool and relatively few practitioners recommend it to their clients. This study shows that the twelve step program could be a valuable tool to add to existing treatment methods, especially as a form of aftercare to help maintain abstinence.
Unexpectedly, there was no difference in life satisfaction at T2 or the difference in life satisfaction between T1 and T2 for participants who attended the twelve step self-help groups more frequently, compared to the participants who attended less frequently. One possible explanation for this result could be the fact that an average of 12 months recovery has not yet changed the quality of life significantly enough. Laudet, Morgen & White (2006) found that quality of life for recovering substance abusers improved over time. In their sample though, participants were in recovery for an average of 26.5 months, more than double the 12 months that was recorded for the present study.
Secondly, variance in life satisfaction scores appear to be determined more by factors outside of this study. This is supported by the fact that participants who had higher life satisfaction scores directly upon completing their therapy also had higher life satisfaction scores one year after treatment. It seems that life satisfaction remained constant throughout the year for most participants, regardless of both twelve step self-help group attendance and abstinence.
An important strength of the current study is the fact that it is the first time in the Netherlands that the potential of the twelve step program is researched. Plenty of research has been done in the United States, this is the first time it was tried to replicate the results in the Netherlands. Also, this study looked both at abstinence as well as at quality of life as measures of sustainable recovery whereas most studies look at abstinence alone. The fact that two points in time were compared also speaks for the present study, as it suggests a hint towards the causality of the effect, however small that hint may be.
The biggest limitation of the present study is the fact that the sample size is relatively small. This prevented more sophisticated methods, such as Structural Equation Modeling, from being used. Second, due to the fact that the measures consisted of self-report interviews conducted by an employee of the addiction care clinic where participants have completed their treatment, there exists a high risk of bias. Some clients actually reported a turn for the worse as a reason not to participate in the study. Perhaps clients with relatively successful recovery rates might have been more likely to participate in the study. This would explain the high rates of abstinence reported by the participants. Furthermore, clients may have found it embarrassing to report negative abstinence rates a year into their recovery, potentially further explaining the high abstinence rates. Lastly, despite the two points in time at which measurements were taken, no hard statements can be made about causality. To be able to truly predict whether twelve step self-help group attendance has an effect on post treatment abstinence and quality of life, a double blind experiment would be needed where two random selections of participants were assigned a group that would and a group that would not attend the twelve step self-help groups after they have completed treatment.
The present study is just a very small step towards investigating the potential of twelve step self-help groups as a viable aftercare tool in the recovery of those suffering from substance abuse. Future studies with greater sample sizes and more sophisticated statistical analyses are necessary to research all the factors influencing sustainable recovery and the potential use of the twelve step program.
This study suggests however that those future studies are worth conducting: the effect that was found offers the possibility that the twelve step self-help groups could indeed help recovering substance abusers maintain abstinence, thereby reducing the cost of addiction care for society as a whole.
Guus Teeuwen – Tilburg University
Borthwick-Duffy, S. A. (1992). Quality of life and quality of care in mental retardation. In Rowitz, L. (Ed.), Mental retardation in the year 2000 (pp. 52-66). Berlin: Springer-Verlag.
Van den Brink, W. (2005). Verslaving, een chronisch recidiverende hersenziekte. Verslaving, 1(2), 47-53.
Boyd, C., Leff, B., Weiss, C., Wolff, J., Hamblin, A., & Martin, L. (2010). Faces of Medicaid: Clarifying multimorbidity patterns to improve targeting and delivery of clinical services for Medicaid populations. Center for Health Care Strategies. Retrieved from http://www. chcs. org/publications3960/publications_show. htm.
Cook, C. C. (1988). The Minnesota Model in the Management of Drug and Alcohol Dependency: miracle, method or myth? Part I. The Philosophy and the Programme.
British Journal of Addiction, 83(6), 625-634.
Corveleyn, J., & van Limbergen, S. (2001). Het Minnesota-model: een stappenbenadering van verslavingsproblematiek. Tijdschrift voor psychotherapie, 27(5), 150-160.
Dennis, M., & Scott, C. K. (2007). Managing addiction as a chronic condition. Addiction Science & Clinical Practice, 4(1), 45.Estimates of A.A. Groups and Members (2015). Retrieved from http://www.aa.org/assets/en_US/smf-53_en.pdf
Felce, D., Perry, J. (1995). Quality of life: Its definition and measurement. Developmental Disabilities, Volume 16, Issue 1, 1995, 51-74.
Fiorentine, R., & Hillhouse, M. P. (2000). Drug treatment and 12-step program participation: The additive effects of integrated recovery activities. Journal of Substance Abuse Treatment, 18(1), 65-74.
Geelen, K. (2003). Zelfhulpgroepen en 12 stappenprogramma’s. Amersfoort: Resultaten Scoren.
Group, P. M. R. (1998). Matching patients with alcohol disorders to treatments: Clinical implications from Project MATCH. Journal of Mental Health, 7(6), 589-602.
[Homepage for Sex and Love Addicts Anonymous], (n.d.). retrieved from http://www.slaafws.org/
Kingree, J. (2013). Twelve-Step Facilitation Therapy. Interventions for Addiction: Comprehensive Addictive Behaviors and Disorders. Elsevier Inc., San Diego: Academic Press, 137-146.
Kingree, J. B., & Thompson, M. (2011). Participation in Alcoholics Anonymous and post-treatment abstinence from alcohol and other drugs. Addictive behaviors, 36(8), 882-885.
Van Laar, M. W., Cruts, A. A. N., Van Ooyen-Houben, M. M. J., Meijer, R. F., Croes, E. A., Ketelaars, E. A., Van der Pal, P.M., & Van Dijk, J. J. (2013). Nationale Drug Monitor.
Laudet, A. B., Morgen, K., & White, W. L. (2006). The role of social supports, spirituality, religiousness, life meaning and affiliation with 12-step fellowships in quality of life satisfaction among individuals in recovery from alcohol and drug problems.
Alcoholism treatment quarterly, 24(1-2), 33-73.
Membership Survey (2014). Retrieved from http://www.aa.org/assets/en_US/p48_membershipsurvey.pdf
Montgomery, H. A., Miller, W. R., & Tonigan, J. S. (1995). Does Alcoholics Anonymous involvement predict treatment outcome?. Journal of substance abuse treatment, 12(4), 241-246.
Morgenstern, J., Kahler, C. W., Frey, R. M., & Labouvie, E. (1996). Modeling therapeutic response to 12-step treatment: Optimal responders, nonresponders, and partial responders. Journal of Substance Abuse, 8(1), 45-59.
Priebe, S., Huxley, P., Knight, S., & Evans, S. (1999). Application and results of the Manchester Short Assessment of Quality of Life (MANSA). International journal of social psychiatry, 45(1), 7-12.
Schippers, G. M., Broekman, T. G., Buchholz, A., & Rutten⁴, R. (2009). Introducing a new assessment instrument: The Measurements in the Addictions for Triage and Evaluation (MATE). Sucht, 55(4), 209-218.
Smith, K., & Larson, M. (2003). Quality of life assessments by adult substance abusers receiving publicly funded treatment in Massachusetts. American Journal of Drug and Alcohol Abuse, 29, 323-335.
Titus, J., Dennis, M., White, M., Godley, S., Tims, F., & Diamond, G. (2002). An examination of adolescents’ reasons for starting, quitting, and continuing to use drugsand alcohol following treatment. Poster presented at the 64th Annual Scientific
Meeting of the College on Problems of Drug Dependence, Quebec City, June 813.
Troyer, T. N., Acampora, A. P., O’Connor, L. E., & Berry, J. W. (1995). The changing relationship between therapeutic communities and 12-Step programs: A survey.
Journal of Psychoactive Drugs, 27(2), 177-180.
United Nations Office on Drugs and Crime (2015). World Drug Report 2015. United Nations publication, Sales No. E.15.XI.6
Ventegodt, S., Merrick, J., & Andersen, N. (2003). Quality of life theory I. The IQOL theory: An integrative theory of the global quality of life concept. Scientific World Journal, 13, 1030-40.
Wilson, B. (2015). Alcoholics Anonymous: Big Book. AA World Services.
Witbrodt, J., Mertens, J., Kaskutas, L. A., Bond, J., Chi, F., & Weisner, C. (2012). Do 12-step meeting attendance trajectories over 9 years predict abstinence? Journal of substance abuse treatment, 43(1), 30-43.
White, W. (2004). Recovery: The next frontier. Counselor, 5, 18-21.
World Health Organization. (2014). Basic documents. World Health Organization.