Background and rationale {6a}
Tobacco consumption is one of the leading risk factors for early death and disability worldwide [
1]. Continued smoking is regarded as a major risk factor in the development of severe medical conditions, such as cancer [
2], pulmonary disease [
3] and cardiovascular disease [
4,
5]. Moreover, due to productivity loss and high follow-up treatment costs, it imposes a heavy burden on the economy [
6]. Successful smoking cessation, on the other hand, can have a significantly positive impact on life expectancy [
7,
8] and quality of life [
9], even after decades of smoking.
Research shows that the majority of smokers wish to reduce (30%) or even quit (59–68%) smoking [
10,
11]. However, nicotine dependence is a complex clinical disorder, which often takes a chronic course [
12]. Therefore, spontaneous unassisted quit attempts are common but not very promising: 60% of unassisted quit attempts fail within the first 2 weeks, 81% suffer a relapse within the first month and 95% suffer a relapse within the first year of abstinence [
13‐
15]. In contrast, a combination of evidence-based pharmacotherapeutic and behavioral therapeutic interventions for smoking cessation is advised [
15‐
17] and was proven effective in a large-scale Cochrane review in 2014 [
18]. However, evidence for long-term effectiveness is relatively low. Even with a combination of different evidence-based approaches for smoking cessation, only up to 20% of smokers achieve abstinence over a period of at least 6 months [
19].
In an effort to increase the long-term efficacy of smoking cessation for strong addictions, the American Society of Addiction Medicine (ASAM) developed an algorithm to intensify procedures for smoking cessation from unassisted self-help over counseling and outpatient group therapy (combined with medication) to a residential therapy away from the patient’s daily environment and habits [
20]. It can be assumed that high-intensity residential smoking cessation therapy has several advantages over interventions in outpatient contexts [
21]. Most smokers live in environments that contain a wide range of behavioral cues for smoking and triggers associated with nicotine consumption. Residential smoking cessation therapies enable increased environmental control and a cue-free environment, which is especially crucial to prevent relapses within the first 24 h of smoking cessation [
22‐
24]. In addition, the residential setting enables high-frequency smoking cessation therapy and complementary supportive interventions from a multiprofessional team, which could be important to establish a new day structure and provide the opportunity for learning and testing novel skills to facilitate long-term abstinence (cf. [
25‐
27]). Complementary interventions like physical activity and relaxation techniques can further cease craving as well as other nicotine withdrawal symptoms [
27‐
29]. The close support from therapists and the various activities within the patient group foster group cohesion and could improve the sense of social support, which is an important factor in the initiation and maintenance of abstinence [
30].
Empirical studies on residential smoking cessation predominantly focus on brief counselling or highly selective groups to which patients with primary health issues other than smoking are admitted. Thus, resources to support smoking cessation during residential therapy are mostly limited to one brief counselling appointment, ranging from 5 min to 2 h, self-help materials and supplementary follow-up calls after discharge. For a detailed overview, see Kazemzadeh et al. and Rigotti et al. [
31,
32]. Different scientific reviews have shown brief counseling interventions to be cost-effective as first-line therapy for smokers, yet long-term abstinence rates remain rather low [
26,
31‐
35]. There is reason to doubt that a brief therapy session allows for enough support of motivational and volitional processes as well as development and evaluation of new behavioral patterns for long-term abstinence. In accordance with evidence-based outpatient therapy, residential therapy sessions should also take at least several hours to adequately incorporate an abstinence decision, planning, environmental control, risk assessment and relapse prevention (cf. [
36,
37]). Only a few published studies have focused on more extensive residential smoking cessation therapies. These relate to uncontrolled or cohort studies with limited methodological quality. However, outcomes suggest significantly increased 6-month or 12-month abstinence rates from 42.6 to 64.7% [
21,
38‐
43]. In a large American cohort study with 226 residential smokers, Hays et al
. [
21] reported significantly higher 6-month abstinence rates of 52% from 8-day residential smoking cessation therapy directly compared to 27% in outpatient therapy with 4327 patients, conducted from the same research group. It should be noted, however, that the total time provided for smoking cessation therapy in the inpatient group largely exceeded that in the outpatient group, which could have led to a strong dose–response effect [
21]. These results are consistent with evidence from our uncontrolled pilot study that found 6-month abstinence rates of 50% for a residential smoking cessation therapy [
44]. Comparatively high abstinence rates of up to 12 months have been reported in an American study with a 7-day residential smoking cessation (57% [
40]) and in studies from Austria implementing a 21-day residential format (63.3% and 42.6% in studies with heavily dependent smokers [
42,
43]), but with all studies missing control groups. Lastly, a 5-day stepwise residential nicotine cessation program has shown satisfactory abstinence rates of 31% at follow-up exceeding 2 years, even when counting participants who could not be reached as smoking [
41]. In Germany, the vast majority of evidence-based therapeutic smoking cessation is conducted in an outpatient setting on a weekly basis over the course of 3–8 weeks. Scientific evaluations of residential therapy for smoking cessation are missing completely.
In conclusion, preliminary evidence suggests that residential smoking cessation therapies contain specific characteristics that could significantly increase abstinence rates. Yet the effectiveness of comprehensive smoking cessation therapy in a residential setting has to be determined in a scientific study design. To date, there are no data available from randomized controlled trials on the efficacy of residential therapy exclusively for smoking cessation. To bridge this gap, we are conducting a randomized controlled trial on the long-term efficacy of a newly designed short-term residential therapy with intensive provision of therapeutic modules, exclusively for smoking cessation. Considering the large number of evidence-based outpatient smoking cessation therapies in Germany, we are carrying out a comparative efficacy trial of residential therapy against the outpatient standard therapy. Depending on the outcome, this therapeutic concept may serve as a new format which can be applied to other medical centers without trained personnel. Furthermore, the new model might substantially influence future cessation therapies and provide deeper insight into intrapersonal determinants (e.g. self-efficacy expectation) and their interaction in smoking cessation.