Non-pharmacological treatment of gambling disorder: a systematic review of randomized controlled trials

Gambling disorder (GD) is the term used to define a persistent and recurrent pattern of gambling that is associated with substantial distress or impairment, according to the fifth edition of the Diagnostic and Statistical Manual (DSM-5) [1]. The symptoms associated with this disorder are very similar to those seen in addictive disorders. Thus, in the DSM-5, GD is now classified as an addictive disorder rather than as an impulse control disorder (in DSM-IV) [2]. As Shaffer and Korn observed, patients with disorders such as kleptomania or pyromania (impulse control disorders) feel overwhelmed by their impulses to act and then, feel a sense of relief after having acted. In contrast, patients with GD find their gambling pleasant and only when they stop gambling or suffer losses, they begin to feel distress, as it happens in substance use disorders [3]. In fact, GD is now the first and only formal behavioural addiction in the DSM-5 [2]. Although any pharmacological treatment has yet to be approved for GD, many studies have already had promising results regarding its efficacy, both in pharmacological-only schemes and in combination with psychotherapies [4]. When combined, better rates of patient retention were found, in comparison to pharmacotherapy-only treatments [4]. Also, Topiramate combined with behavioural therapy could be used to treat patients without comorbidities, while Escitalopram may be effective for the treatment of patients with co-occurring affective disorders [2].

While the pharmacological treatment addresses the dysregulation in neurotransmitter systems, non-pharmacological treatments have a different approach, with a main focus on the behaviour, cognition and motivation of the patients, addressing the psychological determinants of gambling [2]..

Cognitive-behavioural therapies (CBT) are the most commonly used to treat GD [2]. The cognitive component approaches the thoughts, attitudes, and beliefs of the patients, that are the root of the behavioural problems, like gambling cravings or urges [5]. The behavioural component’s objective is to identify external triggers, practising with the patients their response to those triggers, and to find and promote gambling alternatives [2]. The aim of cognitive therapies (CT) is to correct cognitive distortions and irrational thoughts. Examples of these are patients’ overconfidence in their ability to identify systems of winning, beliefs that some behaviours or rituals may help collect wins, and even some statistically wrong beliefs about the games [5]. The objective of exposure therapies (ET) with response prevention is to induce gambling desires and urges in the patients, by exposing them to a gambling environment or by giving them gambling cues, and then, to teach them how to resist those desires in a gradually more self-controlled way [6]. Motivational intervention therapies consist in a counselling approach focused on the person, helping them to explore and resolve ambiguities, what enhances the willingness to change behaviours [7]. The position of the interviewer is non-judgemental, non-confrontational and non-adversarial. Instead, it is collaborative, induces patients’ own motivation and honours their autonomy [2, 8]. This therapy’s intention is to motivate the patients to continue their treatment, considering that two-thirds of GD patients who seek treatment do not engage in it, giving up before it is completed [2]. The main objective of psychodynamic psychotherapy is to identify the meaning behind current behaviour and to resolve conflicts that may have led to it. Furthermore, this therapy focuses on reducing the guilt and shame associated with the consequences of pathological gambling [9]. Other types of therapies will also be reviewed in this systematic review, for example: self-help programmes based on the previous describe therapies; a systemic-based treatment, in this case, couples therapy, that focuses on the patients’ significant others, integrating them in the treatment process; a 12 step facilitated therapy, with the basic principles of gamblers anonymous; and physical activity, that has proved to be efficient in reducing depression and anxiety. Cowlishaw’s et al. [5] systematic review studied the efficacy of CBT, motivational interviewing, integrative therapies and other psychological therapies. Their results supported the efficacy of CBT in reducing gambling behaviour and symptoms, while motivational interviewing only reduced gambling behaviour. The authors also concluded that integrative therapies and other psychological therapies were beneficial, however, there were few studies and evidence to evaluate them. Gooding’s et al. [10] review concluded that cognitive therapy, motivational interviewing and imaginal desensitization had significant results. The authors also stated that when different types of therapy were compared, cognitive therapy was the more advantageous. In Petry’s et al. [11] review, it was concluded that although patients with less symptoms could benefit from minimal interventions, for patients with more severe gambling pathology some therapist contact may be necessary for them to benefit from the therapies.

The main objectives of this systematic review were to:

The main objective of the present review was to synthesise and compare the efficacy and durability of treatment effects of various non-pharmacological therapies for GD. The general outcome in the included studies was improvements on gambling symptoms, severity and/or behaviour, assessed by the scales and scores mentioned, and by measures like gambling frequency, money spent gambling or time spent gambling. Nine of the included studies (40.91%) achieved the outcomes with statistical significance and confirmed the efficacy of the treatments tested [6, 14, 25, 36‐39, 50‐52]; nine other studies (40.91%) confirmed the efficacy of the treatments tested, but some of the outcomes did not reach significance [16, 18, 21, 28, 29, 41, 48, 49]; and 4 of the included studies (18.18%) were not able to confirm the efficacy of the therapies, because the outcomes were non-significant [20, 31, 35, 47]. Nonetheless, every study obtained results in favour of the therapies, despite some of them not being statistically significant. Some therapies, although having proved its efficacy, did not reach significance, because their trial designs did not include a waitlist group, only active treatment groups.

Considering the trials that addressed CBT, the evidence confirmed this treatment’s efficacy, as seven studies registered significant improvements on the majority of the outcomes. Both the individual and the group approach to this therapy had positive results; however, in Dowling et al. [16], the two formats were compared and the individual one proved the be superior at follow-up, with a lower percentage of people diagnosed with GD. Nonetheless, group treatment appears to have some potential benefits, as it utilizes group cohesion and social support to restore the patients’ self-respect and self-efficacy, and allows the patients to learn from other patients’ successes and failures, by promoting observational learning [29]. It is also more time-efficient for the therapist and has better cost-benefits [29]. Two studies tested an internet-based approach for CBT and the results were satisfactory, proving to have a similar efficacy as a face-to-face CBT treatment [25, 37]. The internet-based approach is an innovative format of CBT as it can be offered as a way of enabling gamblers to overcome many of the barriers that prevent them from accessing traditional forms of treatment, as it is more versatile and convenient to the patient than the classical therapy [25]. It increases treatment options, allowing more patients to be treated, maintaining the efficacy of a face-to-face CBT [25]. Other study [20] assessed the possibility of integrating virtual reality exposure sessions to the CBT treatment. It is also an innovative format because, by inducing gambling cravings and desires in the patient, it allows them to practice the CBT techniques safely in the therapist’s office [20]. The study consisted of a pilot trial conducted on a small population and, despite not having achieved significance, this study provided a solid empirical basis, justifying a trial at a larger scale. Longer duration treatments did not appear to be more beneficial than shorter duration ones, as every study that specified the duration had significant improvements on the outcomes. Lastly, the results also supported the short- and long-term efficacy of this therapy, as the improvements remained significant regardless of the duration of the follow-up, that varied from 3 months to 3 years.

This review included 3 studies evaluating CT. Both group [6, 49] and individual [50] formats demonstrated their efficacy, yet, the individual format improved significantly more outcome measures, favouring this format of CT. This therapy revealed to be effective at both moderate and long-term, by maintaining or improving the therapeutic effects at 6-, 12- and 24-months follow-up. ET proved to be effective in one study [6], and when compared to CT at-follow-up, also showed to be superior. Although both therapies showed its efficacy separately, surprisingly, when they were combined (ET + CT) [6], the treatment did not lead to significant improvements. Another study [47] did not find differences between ET and CT, but the authors justified the results with the high drop-out rate of the participants in the trial.

Imaginal desensitization and motivational interviewing also had positive results, with 2 studies [29, 36] proving its efficacy separately, and another 2 studies proving these therapies to be effective when combined [38, 39]. The improvements were maintained at follow-up, being this a valid long-term therapy. When compared to CBT, motivational interviewing therapy revealed to be four times less time-consuming and a lot cheaper [36].

Couples therapy only showed significant improvements on some outcome measures, when compared to a waitlist control [18]. When compared to a standard CBT treatment, the results did not show that involving the patient’s partner in the therapy led to better results [35]. It was only reported a better adherence to treatment, being that this therapy’s biggest strength [35]. Low adherence is one of the biggest obstacles of this disorder’s treatment, alongside with the low rates of treatment-seeking patients (2.6%), as data from gambling helplines have reported [2].

Of the alternative therapies explored through the included studies, the node-link mapping therapy [14, 48] and the twelve-step facilitated treatment [48] proved to be effective, while the personalized feedback intervention [21] did not reach significance on most outcomes at follow-up, and the exercise program [28] only presented significant benefits on reducing gambling comorbidities, failing to reach significant improvements on gambling severity.

The limitations of this review are:

This review’s strengths consist in:

Several psychotherapies included in this review show promising results in the treatment of GD. However, there is a need for additional trials to further confirm the benefits of each therapy, as some of them have been tested in only one trial yet. Further studies should consider testing other therapies than CBT, and some innovative formats, such as the internet-based format, given its advantages. Once these therapies have been studied sufficiently in the treatment of GD and there is a reasonable empirical basis, a gold-standard therapy can be defined. Further studies should also consider different therapies for GD patients that range in severity. Additionally, an updated meta-analysis on this topic is needed.