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Keywords:

  • Addiction;
  • behavior;
  • psychology;
  • substance use disorder intervention

ABSTRACT

  1. Top of page
  2. ABSTRACT
  3. INTRODUCTION
  4. ADDICTION AND MOTIVATION
  5. SOCIAL CONTEXT
  6. FUNCTIONAL BEHAVIORISM/BEHAVIORAL ECONOMICS
  7. THE PSYCHOLOGICALLY INFORMED NEUROSCIENCE OF ADDICTION
  8. INTERVENTION
  9. WEAKNESSES
  10. SETTING THE COURSE: TREATMENT RESEARCH AS AN EXEMPLAR
  11. CONCLUSION
  12. Acknowledgements
  13. References

Aim  To discuss the contributions and future course of the psychological science of addiction.

Background  The psychology of addiction includes a tremendous range of scientific activity, from the basic experimental laboratory through increasingly broad relational contexts, including patient–practitioner interactions, families, social networks, institutional settings, economics and culture. Some of the contributions discussed here include applications of behavioral principles, cognitive and behavioral neuroscience and the development and evaluation of addiction treatment. Psychology has at times been guilty of proliferating theories with relatively little pruning, and of overemphasizing intrapersonal explanations for human behavior. However, at its best, defined as the science of the individual in context, psychology is an integrated discipline using diverse methods well-suited to capture the multi-dimensional nature of addictive behavior.

Conclusions  Psychology has a unique ability to integrate basic experimental and applied clinical science and to apply the knowledge gained from multiple levels of analysis to the pragmatic goal of reducing the prevalence of addiction.


INTRODUCTION

  1. Top of page
  2. ABSTRACT
  3. INTRODUCTION
  4. ADDICTION AND MOTIVATION
  5. SOCIAL CONTEXT
  6. FUNCTIONAL BEHAVIORISM/BEHAVIORAL ECONOMICS
  7. THE PSYCHOLOGICALLY INFORMED NEUROSCIENCE OF ADDICTION
  8. INTERVENTION
  9. WEAKNESSES
  10. SETTING THE COURSE: TREATMENT RESEARCH AS AN EXEMPLAR
  11. CONCLUSION
  12. Acknowledgements
  13. References

Psychology is the study of the individual in context, and as such is fundamental to the clinical and research aspirations of the addiction field. ‘Addiction’ is a hypothesis, namely that a cluster of correlated phenomena are linked by an underlying process (or as Gertrude Stein might have put it, that there ‘really is a there, there’). Without the behavior of persistent, destructive substance use, the environmental availability of the substance itself, and the environmental effects on the behavior, it would be difficult from a scientific viewpoint (and meaningless from a clinical viewpoint) to verify the hypothesis that addiction really exists. This does not limit addiction to observable behaviors but does identify behavior–environment interaction as the central concern.

Throughout this paper we argue for attending to the dynamic multi-dimensional adaptations involved in person–environment interactions. We describe several domains in which psychology, as a focused and flexible science, is making contributions to understanding the development, maintenance and recovery from addiction. From this knowledge base we derive some principles defined in the traditional sense as a ‘a rule or law concerning the functioning of natural phenomena [emphasis added]’[1]. We emphasize how a functional approach provides a useful means of orienting scientific efforts, integrating basic and applied domains and leading transdisciplinary or interdisciplinary research efforts. We close by illustrating how the functional principles derived from this knowledge base contribute to a progressive, incremental science of addiction.

Before proceeding to our review of psychology's substantive and conceptual contributions to the field, we would acknowledge all too briefly psychology's far-reaching contributions to methods. Graduate psychology training programs typically place substantial emphasis on measure development and assessment. One dividend from this investment is many widely used instruments designed by psychologists to assess individuals, families, treatment programs and environments; for example, Moos' coping responses inventory [2] and social ecology scales [3], Halstead & Reitan's neuropsychological testbattery [4] and McLellan and colleagues' [5] Addiction Severity Index. Psychologists have also been leaders in the development and application of quantitativemethods, including accounting for regression to the mean [6], establishing construct validation [7,8] and improving quasi-experimental and experimental treatment evaluations using mediational modeling [9] and meta-analysis [10]. Indeed, experimental studies with human participants in addiction are almost entirely the province of psychologists, including but not limited to many of the methods used to evaluate learning. All these methodological contributions made possible the advances on which we focus in this essay, as well as innumerable advances that space limitations will prevent us from discussing here.

ADDICTION AND MOTIVATION

  1. Top of page
  2. ABSTRACT
  3. INTRODUCTION
  4. ADDICTION AND MOTIVATION
  5. SOCIAL CONTEXT
  6. FUNCTIONAL BEHAVIORISM/BEHAVIORAL ECONOMICS
  7. THE PSYCHOLOGICALLY INFORMED NEUROSCIENCE OF ADDICTION
  8. INTERVENTION
  9. WEAKNESSES
  10. SETTING THE COURSE: TREATMENT RESEARCH AS AN EXEMPLAR
  11. CONCLUSION
  12. Acknowledgements
  13. References

The best scientific evidence for addiction is provided by persistent substance use in the face of cumulative costs, such as psychological distress, social conflict and physical harm to health.

Addiction is not simply a physiological process, but the action of multi-dimensional individuals behaving in a particular fashion in certain contexts. Although many professional and lay individuals speak of addiction as if it were synonymous with tolerance and withdrawal, both of these phenomena can occur without addictive behavior [11]. Indeed, even if we developed a blood test that could measure precisely the degree of an individual's physical tolerance to a drug, it would be hard to convince ourselves or that person that they were addicted without the evidence of drug-seeking and using, i.e. a particular behavior–environment interaction. In addition to making psychology of central relevance to understanding addiction, this distinction also aids in the interpretation of research findings. It may explain, for example, why an episode of sustained abstinence in out-patient treatment predicts subsequent abstinence when detoxification alone does not. The change in the persistent behavior, not the absence of the chemical alone, improves the likelihood of future abstinence [12].

Descriptions of addiction often use terms such as ‘overwhelming desire’ or ‘out of control’ to describe the persistence of substance use in the face of damaging consequences [13]. Yet behavior that looks ‘out of control’ to the observer is in fact an individual's response to their environment and perceived options at the time. Models of motivation attempt to characterize the processes underlying these seemingly irrational choices. These models posit a range of motivations. Stated generally, people use drugs because drugs feel good (positive reinforcement [14], because drugs reduce or remove the experience of feeling bad (negative reinforcement [15]), because brain processes enhance the reward value of substances over time to the point that automatic addictive behaviors occur without thinking (a combination of the effects of drugs on the brain's reward systems, particularly dopamine signaling in the nucleus accumbens, respondent conditioning and incentive sensitization [16–18]) and because of other cognitive processes (e.g. expectancies, beliefs, mental representations, self-efficacy and coping [19]. More recent models synthesize these various dynamic motivations [13,20]). Notably, all the above models are concerned with understanding how and why addicted individuals persistently respond to certain immediate rewards [13].

SOCIAL CONTEXT

  1. Top of page
  2. ABSTRACT
  3. INTRODUCTION
  4. ADDICTION AND MOTIVATION
  5. SOCIAL CONTEXT
  6. FUNCTIONAL BEHAVIORISM/BEHAVIORAL ECONOMICS
  7. THE PSYCHOLOGICALLY INFORMED NEUROSCIENCE OF ADDICTION
  8. INTERVENTION
  9. WEAKNESSES
  10. SETTING THE COURSE: TREATMENT RESEARCH AS AN EXEMPLAR
  11. CONCLUSION
  12. Acknowledgements
  13. References

Addictive behavior occurs within a social context, which can serve as a risk or protective factor. Social contexts and individuals influence one another.

What are the contexts that influence the above-described motivations? Psychology has led the field in identifying the importance of social connection in addiction, including the conceptualization and measurement of the social ecology in which addicted people receive care and in which they live [21,22]. Social context serves as both a risk factor and protective factor for substance use, playing an important role in addiction's initiation, escalation, maintenance and relapse; and conversely in its prevention, treatment and long-term resolution. Relevant social contexts include the family, provider–patient relationships, treatment environment, peer groups and friendship networks, work settings, self-help organizations, neighborhoods and cultural groups, including religious/spiritual communities. As just a few examples, research in which psychologists have been involved has shown that association with substance-using peers is a major risk factor for initiation, escalation and relapse [23]; that the quality of provider–patient relationships contributes to patient retention in substance use disorder treatment [24]; that participation in a 12-Step community after treatment facilitates ongoing recovery [25]; that improving parental functioning and resources improves substance abuse outcomes for adolescents [26]; and that participation in organized religion and the family and social contexts that promote such participation are among the strongest predictors of not initiating substance use in children and adolescents [27]. Clearly, the dynamic interface between the social group and the individual has a powerful influence on addiction.

Several general psychological theories describe the relationships between social context and individual addictive behavior. Among these, social control theory emphasizes the motivational effects of the bonds between group members, social learning theory emphasizes the importance of role models in the development of substance-related behaviors and attitudes, and stress and coping theory emphasizes the impact of stressors resulting from social disorganization on the coping resources of the individual [28]. All these approaches describe influence processes moving bidirectionally between individuals and their social setting [21]. Current psychological research is focused on characterizing these mutual influence processes; for example, some of the dynamic adaptational interactions between environments and individuals described below.

FUNCTIONAL BEHAVIORISM/BEHAVIORAL ECONOMICS

  1. Top of page
  2. ABSTRACT
  3. INTRODUCTION
  4. ADDICTION AND MOTIVATION
  5. SOCIAL CONTEXT
  6. FUNCTIONAL BEHAVIORISM/BEHAVIORAL ECONOMICS
  7. THE PSYCHOLOGICALLY INFORMED NEUROSCIENCE OF ADDICTION
  8. INTERVENTION
  9. WEAKNESSES
  10. SETTING THE COURSE: TREATMENT RESEARCH AS AN EXEMPLAR
  11. CONCLUSION
  12. Acknowledgements
  13. References

Addictive behavior interacts dynamically and lawfully with its environment.

The basic principles of learning and conditioning observed by Thorndike [29] and other psychologists (i.e. operant and respondent paradigms) continue to provide a framework for understanding the interactions between environment and addictive behavior. For example, Herrnstein's Matching Law characterizes patterns of interaction between changes in reinforcement opportunities and individual choice [30]. The Matching Law showed that the ratio of behavior distributed between two choices will ‘match’ the ratio of reinforcement distributed across them, expanding the notion of functional relationships to include a broader environmental context rather than just a unitary reinforcer. For example, environments with greater levels of available positive reinforcement in general may make it less likely that a particular positively reinforced behavior, such as substance use, will occur [31]. The Matching Law has provided the basis for many behavioral economic theories of choice which attempt to quantify the relationships between benefit/cost ratios of substance consumption and benefit/cost ratios of other activities [32].

We would note here that ‘reinforcement’ is a frequently misunderstood term that refers to a fundamentally personal phenomenon. The form or topographic features of an event do not define it as a reinforcer (e.g. giving a weeping client candy is unlikely to reinforce continuing discussion of the costs of using); rather, reinforcement refers to the functional impact of the experienced event for that particular person (more technically, whether the event functions to increase the probability of the behavior it follows in a specific context [33,34]). Reinforcement is a function of a multi-dimensional person interacting with a complex environment. Attention, perception and motivation, for example, may be critical in establishing how a reinforcer functions in any given setting.

Learning principles characterize certain dynamic interactions between individuals and their environments, and also offer a unique bridge for integrating basic and applied domains. The most successful psychosocial treatments for addiction have applied basic functional models to clinical settings [35]. Contingency management, for example, an empirically supported treatment for stimulant abuse and for promoting retention in methadone maintenance programs, applies operant processes of contingent reinforcement such as vouchers for clean urine tests and take-home doses for attending clinic counseling sessions [36]. Motivational interviewing, an empirically supported cognitive behavioral treatment for substance abuse, positively reinforces treatment relevant behaviors such as ‘change talk’ using interpersonal processes within the therapy session (i.e. support, empathy and contingent feedback; [37,38]).

Dynamic functional processes of problem resolution may also occur outside treatment settings [39]. The contingency of reinforcement mediates contingency management treatment, as specified in its functional model. Yet treatment is only one structured context where these principles operate. Other social contexts such as 12-Step fellowships or religious communities may also reduce the likelihood of drinking or relapse by naturally reinforcing adaptive alternatives to substance use, e.g. sponsors in 12-Step programs may provide social support contingent on abstinence and encourage socially normative activities such as working, self-care, family life, recreational activities, etc. [40]. Communities bring these functional processes into play without the conceptual framework of behavioral psychology, e.g. ‘reinforcement’, etc. [41].

THE PSYCHOLOGICALLY INFORMED NEUROSCIENCE OF ADDICTION

  1. Top of page
  2. ABSTRACT
  3. INTRODUCTION
  4. ADDICTION AND MOTIVATION
  5. SOCIAL CONTEXT
  6. FUNCTIONAL BEHAVIORISM/BEHAVIORAL ECONOMICS
  7. THE PSYCHOLOGICALLY INFORMED NEUROSCIENCE OF ADDICTION
  8. INTERVENTION
  9. WEAKNESSES
  10. SETTING THE COURSE: TREATMENT RESEARCH AS AN EXEMPLAR
  11. CONCLUSION
  12. Acknowledgements
  13. References

Addiction involves learned responses to a drug and to the environments in which drug taking is experienced. The brain encodes these learning histories as neuroplastic adaptations including alterations in the mesolimbic dopamine reinforcement systems.

Learning principles link not only basic and applied domains within psychology but also psychology and other disciplines, thus offering one natural point of interdisciplinary integration. Psychological data derived from the application of learning principles in animal models have been essential to progress in the neurobiology of addiction. As stated recently in this journal, the agenda of modern addiction brain science is to validate molecular and neurochemical candidate systems functionally by demonstrating their causal relationships with addictive processes [42]. Basic behavioral methods provide a framework for evaluating the function of candidate neurobiological systems (e.g. place preference paradigms, drug self-administration, reinstatement of drug seeking, etc.). Relevant systems include those involved in the neuropharmacological processes of behavioral response to substances as well as the neuroadaptive mechanisms within specific neurocircuits that may mediate addictive behavior, such as the circuits recruited in the transition from occasional use to uncontrolled use, from positively reinforced to negatively reinforced addictive behavior, or from compulsive use back to controlled use or abstinence. Studies of mesolimbic dopamine circuits, for example, have identified neuroadaptive processes linked to reinforcement in general (e.g. [43]) and have also identified effects specific to drugs of abuse that may lead to the overvaluation of drug rewards as compared to natural reinforcers [44,45].

Cue-elicited craving offers one example of psychology's leadership role in transdisciplinary neuroscience collaborations [46]. The presence of cues associated with the availability of learned reinforcers such as alcohol or other drugs will increase behavioral responding for these rewards [47]. Cue conditioning is a key element in the development and maintenance of addiction, and cue-elicited craving a key aspect of relapse [48]. The neuropeptide cortisol-releasing factor (CRF) offers one possible pathway for the relationship between stress, cue conditioning and relapse in habitual users [49]. CRF released in the nucleus accumbens shell in response to stress may increase the incentive salience of cues signaling the availability of learned reinforcers, increasing behavioral responding for rewards when such cues are present. Because drug withdrawal can be a significant stressor, potently releasing CRF in limbic brain circuits, this process may become a negative reinforcement cycle driving ongoing drug use, described as ‘the downward spiral of addiction’[50]. Notably, this explanation describes neurobiological mechanisms conceptualized in terms of behavioral principles of negative reinforcement.

Cue-elicited craving has been associated with neuronal processing in the anterior cingulate cortex and frontal cortex [51–53]. A related promising line of neuroscience research examines how the frontal cortex inhibits automatic responding in immediate decision-making tasks. Performance on executive function/task-switching tests (which include inhibition) has been associated with neural processing in the prefrontal cortex in both neuroimaging and electrophysiological studies [54–56]. For example, several studies have demonstrated that activity in areas of the frontal cortex is associated with the ability to alter responding in a well-trained signaled response task [57,58]. These studies are providing important information on individual decisions about behavior choice, and about how alternate behaviors can be produced even when a given response has become ‘automatic’ and favored. Understanding this process has obvious importance for modifying impulsive behavior in addiction. In particular, these studies have shown that the ability to inhibit automatic responding by the frontal cortex is easily overwhelmed by loading of working memory, which occurs when experiencing stressors such as cravings. In other words, a person may not be able to stop a well-trained behavior such as drug taking using frontal cortex inhibition when they are experiencing high levels of cue-elicited craving.

Psychology has thus expanded, and at times transcended, its own discipline, applying learning principles and other contributions toward improving our understanding of the neuroanatomical substrates of affective and cognitive processes such as stress and executive function. The field continues to play a pivotal role in identifying the dynamic neurobiological processes involved in vulnerability to addiction, consequences of substance use and important aspects of addiction including relapse, loss of control, craving and drug choice.

Psychology can also serve as a useful guard against concluding that because brain systems are involved in addiction, all solutions to addiction are found in the brain (or in genes; see [59]). The environmental stressors that facilitate certain genetic expressions are not equal in their effects across individuals. Psychological factors influence how stressors are appraised and coping responses can minimize or augment their impact; and changes in the environment can change individual behavior. The behavior economic literature, for example, suggests the importance of restricting access to substances as a strategy for reducing addiction, as it raises the behavioral costs of use and thereby increases the attractiveness of other behaviors. This has been well demonstrated in the effect of cigarette cost on smoking [60].

INTERVENTION

  1. Top of page
  2. ABSTRACT
  3. INTRODUCTION
  4. ADDICTION AND MOTIVATION
  5. SOCIAL CONTEXT
  6. FUNCTIONAL BEHAVIORISM/BEHAVIORAL ECONOMICS
  7. THE PSYCHOLOGICALLY INFORMED NEUROSCIENCE OF ADDICTION
  8. INTERVENTION
  9. WEAKNESSES
  10. SETTING THE COURSE: TREATMENT RESEARCH AS AN EXEMPLAR
  11. CONCLUSION
  12. Acknowledgements
  13. References

Many empirically based substance use disorder behavioral interventions facilitate recovery from addiction, although not necessarily for the reasons specified in their theories.

Research indicates that well-specified psychosocial substance use disorder treatments have a positive impact on outcome, and there are many such treatments from which to choose. The US National Institute of Drug Abuse, the British Association of Psychopharmacology [61] and the Swedish Council of Health Care Technology Assessment [62] are among notable organizations who have compiled lists of empirically supported treatments for addiction and its prevalent comorbidities. Most of these treatments were developed by psychologists based on psychological theories, including motivational interviewing, social skills training, combined behavioral and nicotine replacement therapy for nicotine addiction, structured family and couples therapy and community reinforcement approach and family training [63].

Psychologists have taken a leading role in proposing new theories of treatment and in promoting rigorous treatment evaluation, including the development of treatment integrity measures and other methodological innovations (e.g. despite occasionally being portrayed as a ‘touchy-feely’ irrationalist, the psychologist Carl Rogers helped begin the tradition of rigorous evaluation of psychotherapies; see [64]). The results of trials comparing well-specified behavioral therapies (and at times behavioral versus pharmacotherapies) show that different well-specified substance use disorder treatments usually have similar levels of efficacy [65–67]. However, exceptions to this rule exist. For example, a recent meta-analysis of cue–exposure therapy [68] yielded equivocal evidence for its efficacy and also failed to support its specified mediating model, i.e. reductions in cue–reactivity are not produced by this treatment and/or do not effect the critical behaviors [69].

Large controlled trials including mediational analyses have rarely identified a treatment with reasonable evidence for its purported mechanism of change. Among the few exceptions appear to be contingent reinforcement of abstinence in cocaine addiction [70] and Alcoholics Anonymous participation in 12-Step facilitation counseling [71,72]. Accurately identifying mediators is vitally important, because clarifying the critical aspects of treatment may allow us to improve its potency and determine for whom a particular treatment might work [73]. It is not as useful to know, for example, that men do better in certain smoking cessation treatments than women unless we also know why and what to do about it (see [74] for an excellent discussion).

WEAKNESSES

  1. Top of page
  2. ABSTRACT
  3. INTRODUCTION
  4. ADDICTION AND MOTIVATION
  5. SOCIAL CONTEXT
  6. FUNCTIONAL BEHAVIORISM/BEHAVIORAL ECONOMICS
  7. THE PSYCHOLOGICALLY INFORMED NEUROSCIENCE OF ADDICTION
  8. INTERVENTION
  9. WEAKNESSES
  10. SETTING THE COURSE: TREATMENT RESEARCH AS AN EXEMPLAR
  11. CONCLUSION
  12. Acknowledgements
  13. References

Psychology has made major contributions to understanding addiction, but we would be the first to acknowledge that it has also occasionally ‘filled a much-needed gap’ in the field's approach and knowledge. Psychologists have at times tried to explain individual behavior without sufficient appreciation of context. US psychology has been the worst offender, in some ways reflecting the larger cultural narrative that individuals create their own lives and triumph over all contexts (or if they do not, they have only themselves to blame). For example, for every published article concerning ‘drug use and poverty’ in the psychological literature, more than 50 articles focus on ‘drug use and personality’[75]. Callous behavior by societies and governments are justified too easily when problems shaped by powerful environmental forces are attributed entirely to intrapersonal variables. Disregard for context has led to some psychologists making pronouncements on the ‘universal features of addiction’ (among many other features of human existence) on the basis of how small samples of white, middle-class undergraduates have filled out a questionnaire.

Psychologist have also at times over-psychologized ‘addiction’ by not taking drugs sufficiently seriously as environmental features with unique, genuine and powerful properties not determined solely by the individual user's expectancies, psychodynamic conflicts or cognitive biases. Psychologists who market services for alleged ‘addictions’ to work, shopping and television should weigh carefully the public health implications of implicitly equating long days at the office, discounts at Sainsbury's and re-runs of Star Trek episodes with nicotine, heroin and alcohol. The latter three environmental features should be handled differently by programs and policy makers because they are objectively different than the former three, no matter how many people say that they feel addicted to them, ‘just like being addicted to drugs’. The inner life of individuals is, of course, an important part of psychology, but only in the context of environmental features interacting with behavioral responses, and what the individual learns from those interactions. Acontextual theories risk addressing only a small portion of an integrated system, and thus misdirect our attention to less relevant details at the expense of factors related more directly to the phenomenon of addiction [13].

SETTING THE COURSE: TREATMENT RESEARCH AS AN EXEMPLAR

  1. Top of page
  2. ABSTRACT
  3. INTRODUCTION
  4. ADDICTION AND MOTIVATION
  5. SOCIAL CONTEXT
  6. FUNCTIONAL BEHAVIORISM/BEHAVIORAL ECONOMICS
  7. THE PSYCHOLOGICALLY INFORMED NEUROSCIENCE OF ADDICTION
  8. INTERVENTION
  9. WEAKNESSES
  10. SETTING THE COURSE: TREATMENT RESEARCH AS AN EXEMPLAR
  11. CONCLUSION
  12. Acknowledgements
  13. References

What can psychology do in the future to avoid repeating missteps and to break into new directions? Clarifying our theoretical assumptions may help to guide future research efforts. The field of treatment research offers one example.

Decades of research on clinical treatment has led to a substantial knowledge base. We know that treatment benefits a significant proportion of addicted people, and we have a variety of reasonably effective treatments to offer. However, the results of large, well-funded and well-designed treatment research studies such as Project MATCH [76], the UK Alcohol Treatment Trial [77] or the VA Multisite Substance Abuse Treatment Study [78] show that null findings are arguably the single most common outcome in large-scale substance use disorder treatment studies. Although one cannot prove the null hypothesis that treatments do not differ, the consistency of these non-results in well-powered studies suggests that our theories are failing to capture critical factors. It is time to consider additional strategies.

Psychologists have long discussed factors common to different treatment approaches that may be responsible for treatment effects. The therapeutic relationship is the most frequently researched of these so-called ‘common factors’[79]. Although researchers described originally the therapeutic relationship as ‘non-specific’ in an analogy to the pharmacologically inert component of medication, it has become clear that the therapeutic relationship is an active interaction [80,81] that may increase treatment engagement and other recovery-relevant behaviors [24,82]. Currently, the critical question is how the therapeutic relationship functions, i.e. how does the provider interact with the patient in specific processes which change the patient's behavior and are responsible for treatments' effects [83]?

Miller [84] recently distinguished ‘name brand’ treatments from the mediating processes by which treatments exert their effects. Summarizing the current knowledge base on addiction in the biological, psychological, social and intervention research domains, Miller and colleagues drew a number of evidence-based conclusions: addictive behavior is reinforcing, chosen behavior; emerges gradually and occurs along a continuum; does not occur in isolation but as part of behavior clusters; occurs within a family context; responds to changes in reinforcement; is affected by a larger social context; has identifiable risk and protective factors, tends to become self-perpetuating once established; is motivated behavior; and is influenced by the therapeutic relationship [84]. Notably, all these conclusions reflect a functional perspective.

Psychology has an opportunity to lead the addiction field by identifying functional concepts that characterize the multi-dimensional processes responsible for treatments' effects. Clarity about these processes will permit systematic treatment improvement [35,83]. Conducting transdisciplinary research requires a shared conceptual or theoretical framework that integrates knowledge fully across disciplines [85–87]. Among the many contributions discussed previously, psychology has also developed the most precise scientific methodology for validating conceptual constructs (e.g. multi-trait–multi-method matrices); such methods might be used to identify theoretically based functional processes that synthesize research across disciplines [88].

Functional models, by definition, characterize individual–environment interactions, and therefore provide a pragmatic means of changing behavior via environmental factors. For one example, behavior change is more likely with abstinent supportive social reinforcement [28]. In applied settings, treatment personnel who behave in a supportive rather than a confrontational manner appear to improve the likelihood of positive outcomes [82], perhaps by increasing patient involvement [89] and helping patients learn to accept and respond differently to internal states previously associated with using [90]. In a recent study, patients from treatment programs with supportive, involved relationships were more likely to respond adaptively to internal states associated previously with substance use, develop constructive social relationships and achieve long-term treatment benefits. This functional model accounted for 41% of the variance in outcomes 2 years after treatment [41]. Researchers continue to examine the processes involved in socially reinforcing interactions via social neuroscience, basic and clinical process and outcome research.

Emphasis on function provides a common empirical ground for examining the behavior change process across treatment modalities. The pre-existing practices of a variety of treatments and treatment settings include factors related to positive outcomes [41]. Identifying these practices might bring parsimony to the multiplicity of available treatments and aid in dissemination by building on aspects of treatment that providers already deliver. The dissemination gap between empirically supported treatments and substance use disorder treatment provider practice is arguably a result of the failure of researchers and administrators to address the functional aspects of clinicians' behavior. Rather than simply attempting to impose top-down change, viewed from a functional perspective the dissemination question becomes: ‘How do we facilitate behavior change in the treatment provider?’. To answer this question one first needs to understand what providers are doing and then use this information to shape changes in behavior, i.e. build upon constructive evidence-based practices and weaken competing alternatives. Data regarding the functional dimensions of clinician behavior include studies showing that meaningful changes in treatment provision are less likely with a single workshop (e.g. [91]) than with ongoing supervisory feedback [92]. Functional principles offer specific environmentally based ways of facilitating behavior change in both patients and providers, including building on current repertoires, shaping new ways of interacting and providing systematic methods for generalizing behavioral changes [93].

In short, using a functional approach to modeling behavior change directly targets the patient behaviors that lead to better long-term outcomes; serves as a point of integration for interdisciplinary research efforts aimed at characterizing the process of behavior change; provides pragmatic methods for influencing these changes in behavior; and builds upon what programs and providers are already doing in order to improve treatment delivery.

A final compelling reason for focusing scientific efforts on processes of change is that these adaptational or functional principles apply beyond the treatment context. The processes that contribute to improvement in treatment may also be implicated in recovery in mutual help organizations, processes involved in ‘natural’ recovery (which, indeed, is how most individuals overcome addiction), prevention and recovery in religious/spiritual cultural communities, etc. From a functional perspective, treatment essentially provides a structured environment within which to influence (i.e. boost variability in) relevant processes. Thus treatment is particularly important for those who do not have access to these types of context in their natural environment or who are in need of more intense exposure to curative environments. Broadening the lens to include context also entails recognizing that treatment may be simply one chain in a larger causal model [94]. Clients describe their own change process in both intrapersonal and interpersonal terms, embedded in the contexts within and outside the treatment setting [95]. Indeed, causal mediators of treatment may be difficult to find because the critical processes occur outside treatment. For example, Longabaugh and colleagues [96] found that improvement in social skills did lead to improved alcohol treatment outcomes, as described by their theoretical model, but causal chain analyses revealed that these changes in social functioning did not occur within treatment.

Most members of the field concede that addiction research is more informative when it is theoretically based. Less commonly discussed is the fact that our assumptions specify what sort of theoretical explanations are considered adequate and thereby guide the direction of inquiry. In general, the field of psychology has suffered from a proliferation of theories with relatively little pruning [35] (see [13] for an excellent discussion; also [97]). However, the propagation of labels should not be mistaken for scientific progress [98]. Psychology's commitment to rigorous evaluation offers both great progress and humility. We may need to surrender some of our cherished ways of speaking in order to further our ongoing goal of improving interventions that treat and prevent addiction.

CONCLUSION

  1. Top of page
  2. ABSTRACT
  3. INTRODUCTION
  4. ADDICTION AND MOTIVATION
  5. SOCIAL CONTEXT
  6. FUNCTIONAL BEHAVIORISM/BEHAVIORAL ECONOMICS
  7. THE PSYCHOLOGICALLY INFORMED NEUROSCIENCE OF ADDICTION
  8. INTERVENTION
  9. WEAKNESSES
  10. SETTING THE COURSE: TREATMENT RESEARCH AS AN EXEMPLAR
  11. CONCLUSION
  12. Acknowledgements
  13. References

We have adumbrated psychology's contributions to addiction in the social, behavioral, neurobiological and intervention domains. This survey fails to describe innumerable contributions, including much of cognitive psychology, developmental psychology, physiological psychology and neuropsychological assessment. Further, our assumptions and the principles we derive from these domains are our own, and both other assumptions and other interpretations are possible. We simply hope to show the relationship between definitional assumptions, explanations and progress in what we view as a particularly important and vital knowledge base.

The psychologically derived principles or descriptions of the ‘functioning of natural phenomena’ presented here share an assumption, namely that addiction research is concerned fundamentally with interactions between individuals and their environments, and that maintaining clarity about our subject matter will help promote a focused, flexible and progressive addiction science. Future questions include application of these principles to broader social contexts. For example, how might we apply these principles to addiction in the public health and public policy domains [99]?

Addiction involves dynamic adaptations occurring at multiple levels that are influenced by a variety of contexts including but not limited to treatment environments. If we want to improve our understanding of addiction and recovery, we should examine these processes directly. Psychological science is well suited for this endeavor.

Acknowledgements

  1. Top of page
  2. ABSTRACT
  3. INTRODUCTION
  4. ADDICTION AND MOTIVATION
  5. SOCIAL CONTEXT
  6. FUNCTIONAL BEHAVIORISM/BEHAVIORAL ECONOMICS
  7. THE PSYCHOLOGICALLY INFORMED NEUROSCIENCE OF ADDICTION
  8. INTERVENTION
  9. WEAKNESSES
  10. SETTING THE COURSE: TREATMENT RESEARCH AS AN EXEMPLAR
  11. CONCLUSION
  12. Acknowledgements
  13. References

This work was supported by the US Department of Veterans Affairs Office of Mental Health Services and Health Services Research and Development Service. We thank Stephen Maisto, Rudolf Moos and Robert West for extremely helpful comments and discussions.

References

  1. Top of page
  2. ABSTRACT
  3. INTRODUCTION
  4. ADDICTION AND MOTIVATION
  5. SOCIAL CONTEXT
  6. FUNCTIONAL BEHAVIORISM/BEHAVIORAL ECONOMICS
  7. THE PSYCHOLOGICALLY INFORMED NEUROSCIENCE OF ADDICTION
  8. INTERVENTION
  9. WEAKNESSES
  10. SETTING THE COURSE: TREATMENT RESEARCH AS AN EXEMPLAR
  11. CONCLUSION
  12. Acknowledgements
  13. References
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