What happens after five years?: The long-term effects of a four-session Acceptance and Commitment Therapy delivered by student therapists for depressive symptoms

Highlights

• Long-term outcomes of a brief intervention were assessed.

• Intervention was acceptance- and value-based for self-reported depressive symptoms.

• Outcomes were maintained for at least five years after the intervention ended.

Abstract

Brief interventions can be viable treatment options worth consideration in addressing the growing need for treatments of subclinical and clinical depressive symptoms. However, there is uncertainty regarding the long-term benefits of these interventions. The aim was to examine the long-term (5-year) effects of a 4-session Acceptance and Commitment Therapy (ACT) intervention for low mood delivered by novice therapists in order to see whether lasting effects could be achieved cost-effectively with four intervention sessions. Originally, 57 self-referred clients were randomized into two groups: an intervention group and a waiting-list control group which received treatment later. The groups were combined both at the 6-month (n=48) and the 5-year (n=35) follow-up measurements to examine intervention effects. The results indicate a good effect size for depressive symptoms (the Beck Depression Inventory (BDI)): d=1.45 (CI 1.10–1.80) through the five-year study period. All in all, approximately 40% of the participants reported minimal to no depressive symptoms based on the primary outcome measure, the BDI (scores 0–9), both at post- and 5-year follow-up measurements.

Introduction

Depressive symptoms, either clinical or subsyndromal, are often the reason people seek psychological services (Smit et al., 2006), and mood related symptoms impair functioning and affect well-being in terms of both clinically diagnosed depression (Kessler, Chiu, Demler, & Walters, 2005) and those suffering at the subclinical level (Goldney et al., 2004, Horwath et al., 1992, Judd et al., 1996). Meta-analyses indicate that psychological interventions and psychotherapy are effective for both clinical and subclinical depression (Barth et al., 2013, Cuijpers et al., 2009, Cuijpers et al., 2014, Linde et al., 2015), and treatments based on the cognitive-behavioral therapy (CBT) model are among the most studied and reviewed as empirically supported (Cuijpers et al., 2013, Hollon and Ponniah, 2010). They could be regarded as the first-line option for treatment (Hollon, 2016). As depressive symptoms are strongly associated with clinical depression or major depressive episode, effective treatments should be developed and implemented early (Horwath et al., 1992). Depressive symptoms are often encountered in low-level settings which may limit the possibility to offer standard-length psychotherapy (Bijl and Ravelli, 2000, Nieuwsma et al., 2012), and a significant part of those seeking help are new cases advocating for easy and rapid access to treatment to prevent symptoms from worsening (Smit et al., 2006).

Brief psychological interventions may be more readily implemented in low level settings and could offer a viable possibility to an easier access to psychological help in order to diminish suffering (Churchill et al., 2001, Nieuwsma et al., 2012). We argue that those interventions could be a viable alternative to meet the service needs, especially among clients with mild psychological symptoms. Psychological flexibility (Hayes et al., 2004, Kashdan and Rottenberg, 2010) could offer an insight on how to promote psychological health and decrease distress. Psychological flexibility is a core concept in Acceptance and Commitment Therapy (ACT; Hayes et al., 2004; Hayes, Strosahl, & Wilson, 2011), a recent development in the CBT tradition, focusing on acceptance and valued living. Earlier research focusing on acceptance- and value-based interventions has shown promising, positive results regarding a wide variety of psychological and health-related suffering (A-Tjak et al., 2015, Hayes et al., 2006, Powers et al., 2009, Ruiz, 2010), even in a time-limited (3–10 sessions) intervention setting (Hayes et al., 2006, Kohtala et al., 2015, Lappalainen et al., 2007, Lappalainen et al., 2014, Lappalainen et al., 2015). Psychological flexibility is targeted in ACT interventions and mediational data suggests that it is likely to be influencing the positive outcomes, yet the results seem to be somewhat mixed and follow-ups were often at 6 months or less with some exceptions (e.g. Ciarrochi, Bilich, & Godsel, 2010).

We developed a 4-session, semi-structured, individual-oriented ACT-based intervention for self-reported depressive symptoms. An earlier report on our brief intervention (Kohtala et al., 2015) declared it to have had a positive impact on the well-being of the participants: after the intervention, decreases in depressive symptoms and increases in psychological flexibility were found to have been greater than in the parallel waiting-list control group, and these effects were maintained in the intervention group across a 6-month follow-up period.

However, more research is needed to investigate both the effectiveness of very brief psychological interventions and especially their long-term effectiveness, since the maintenance of treatment outcomes is an important factor when assessing interventions to be implemented and disseminated in health care systems. Follow-ups lasting longer than 12 months are rare in psychotherapy research, with a few exceptions. In CBT literature, several CBT-based interventions with long follow-ups have been reported to show promising yet fading results concerning relapse prevention (Fava et al., 1998, Fava et al., 2004, Paykel et al., 2005). Regarding depressive symptoms, research on long-term effectiveness has yielded some cases with good maintenance of treatment outcomes (Andersson et al., 2013, Stagl et al., 2015, Wiles et al., 2016), but research on individual brief interventions with long-term follow-up periods is scarce. Follow-ups beyond the 12-month mark are also rare in ACT as well as in other types of cognitive-behavioral therapies, and the results have been mixed. With respect to the ACT literature, Zettle and Rains (1989) were among the first to report positive results in the treatment of depression yet with only a two-month follow-up. More recently, two studies have examined different modalities of brief ACT interventions (face-to-face and Internet-delivered) for depressive symptoms with an 18-month follow-up (Folke et al., 2012, Lappalainen et al., 2014). Those interventions included individual or group sessions, and reported significant improvements in depressive symptoms, general health and quality of life. Treatment gains were maintained across the 18-month follow-up periods. While there is evidence for the treatment effectiveness of such brief ACT interventions with follow-ups, the longer-term impact is unknown.

Given the scarcity of long-term follow-up data on brief ACT interventions for depressive symptoms, our aim was to gain preliminary long-term data on the effectiveness of a brief ACT intervention for depressive and other psychological symptoms, as well as on psychological flexibility and mindfulness skills. The current study is a follow-up investigation to our earlier study (Kohtala et al., 2015), in which a pre-post comparison with a waiting-list control group was conducted covering a 6-month follow-up period (without the waiting-list comparison group). The current study evaluates the maintenance of that intervention's effects after a period of 5 years. Our primary intention was to study the long-term effectiveness of that brief ACT intervention provided by novice therapists, which had a non-diagnosed population seeking help for low mood. Studies, for example by Forand, Evans, Haglin, and Fishman (2011), Hiltunen, Kocys, and Perrin-Wallqvist (2013), and Öst, Karlstedt, and Widén (2012), suggest that treatments provided by trainees can be effective. Furthermore, we argue that it is also important to investigate the effectiveness of low-cost interventions for the benefit of clients with milder symptoms of depression in order to decrease the possibility of major depressive episodes (Cuijpers et al., 2014, Horwath et al., 1992).