The efficacy of non-directive supportive therapy for adult depression: A meta-analysis

Abstract

The effects of non-directive supportive therapy (NDST) for adult depression have been examined in a considerable number of studies, but no meta-analysis of these studies has been conducted. We selected 31 studies on NDST from a comprehensive database of trials, examining psychotherapies for adult depression, and conducted meta-analyses in which NDST was compared with control groups, other psychotherapies and pharmacotherapy. We found that NDST is effective in the treatment of depression in adults (g = 0.58; 95% CI: 0.45–0.72). NDST was less effective than other psychological treatments (differential effect size g = − 0.20; 95% CI: − 0.32 to − 0.08, p < 0.01), but these differences were no longer present after controlling for researcher allegiance. We estimated that extra-therapeutic factors (those processes operating in waiting-list and care-as-usual controls) were responsible for 33.3% of the overall improvement, non-specific factors (the effects of NDST compared with control groups) for 49.6%, and specific factors (the effects of NDST compared with other therapies) for 17.1%. NDST has a considerable effect on symptoms of depression. Most of the effect of therapy for adult depression is realized by non-specific factors, and our results suggest that the contribution of specific effects is limited at best.

Introduction

Several types of psychotherapy have been found to be effective in the treatment of adult depression, including cognitive behavior therapy (Churchill et al., 2001, Gloaguen et al., 1998), interpersonal psychotherapy (Cuijpers et al., 2010a, de Mello et al., 2001), behavioral activation therapy (Cuijpers et al., 2007a, Ekers et al., 2008), problem-solving therapy (Cuijpers et al., 2007b, Malouff et al., 2007), and possibly psychodynamic therapies (Gerber et al., 2011, Shedler, 2010), and other psychotherapies, such as process-experiential (Greenberg, Elliot, & Lietaer, 1994) and life-review therapies (Bohlmeijer et al., 2003, Hsieh and Wang, 2003). It is not yet clear, however, whether these therapies are equally effective. In a meta-analysis of comparative outcome studies of different psychotherapies, we found that the effects of interpersonal psychotherapy were somewhat larger and the effects of non-directive supportive therapies somewhat smaller than other psychotherapies (Cuijpers, van Straten, Andersson, & van Oppen, 2008). Although these differences were significant, they should be considered with caution because of the small number of comparisons, and the relatively low quality of several included studies. In a recent meta-analysis of interpersonal psychotherapy we could not find support for its superior effects over other therapies (Cuijpers et al., 2011). Furthermore, although we found no significant difference between psychodynamic therapy and other therapies (Cuijpers et al., 2008a, Cuijpers et al., 2008b), a more recent meta-analysis showed that psychodynamic therapy was significantly less effective than other therapies (Driessen, Cuijpers, de Maat, et al., 2010). So, although meta-analyses seem to be an excellent method for examining differential effects of different therapies, there are yet no definite answers to the question whether all psychotherapies for adult depression are equally effective or not.

Although there may be small differences between the effect sizes of different psychotherapies for adult depression, the effects of most therapies do not differ from each other. Furthermore, when differences are found, they tend to be small and unstable. After more than three decades, most quantitative reviews suggest that the different therapies for depression are equally or almost equally effective (Luborsky, 1995, Luborsky et al., 1975, Shadish and Sweeney, 1991, Stiles et al., 1986). This could indicate that most effects of psychological treatments are caused by common, non-specific factors and not by particular techniques (Cuijpers, 1998). These common factors include the therapeutic alliance between therapist and client, belief in the treatment, and a clear rationale explaining why the client has developed the problems (Lambert, 2004, Spielmans et al., 2007). Another possible explanation is that the effects of psychotherapy are realized by a variety of specific therapeutic mechanisms (Butler & Strupp, 1986), but that the number of possible mediators is so large, that small differences between treatments in specific groups of patients (moderation) remain unnoticed due to insufficient statistical power or because our research methods are not sensitive enough (Kazdin, 1986). In this context, it is important to note, that not all patients who receive psychotherapy for depression improve and more still fail to sustain the improvement reached immediately after treatment (Cuijpers, van Straten, Bohlmeijer, Hollon, & Andersson, 2010). The problem then is to discover what works for whom, a venture that would require very large samples and considerable resources.

From this perspective, non-directive supportive therapy (NDST) is an interesting treatment. A considerable number of studies have examined NDST as a treatment for adult depression. Some researchers have included NDST in randomized trials of psychotherapies to control for the nonspecific elements that are common to all therapies, in contrast to the specific techniques of the therapy being tested (Markowitz et al., 1998, McNamara and Horan, 1986, Propst et al., 2002). In other studies, NDST is examined as a treatment that is itself expected to have a full effect on depression (Bower & Rowland, 2006). However, in all of these studies the methods and techniques used in NDSTs are very much the same: an unstructured therapy without specific psychological techniques other than those belonging to the basic interpersonal skills of the therapist, such as reflection, empathic listening, encouragement, and helping people to explore and express their experiences and emotions. In NDSTs the therapist refrains from giving advice or making interpretations, and the therapy typically is not aimed at providing solutions or acquiring new skills. NDSTs are commonly described in the literature as counseling, supportive therapy, or as a non-specific therapy, and include support groups for people with the same comorbid conditions such as cancer (Evans & Connis, 1995) or HIV (Kelly et al., 1993, Markowitz et al., 1998). In the current study, we use the following definition of NDST: a psychological treatment in which therapists do not engage in any therapeutic strategies other than active listening and offering support, focusing on participants' problems and concerns (Arean et al., 2010).

Research on NDST also is of interest because it may give an indication of the relative contribution of specific and non-specific effects to the improvement of depressed people during therapy. Lambert (1992) estimated that 40% of the improvement in clients was caused by extra-therapeutic change, 30% by the therapeutic relationship, 15% by client expectations, and the remaining 15% by specific techniques. Although these estimates have been cited by many, they were not based on empirical data, but rather on the author's impression from reviewing a large number of psychotherapy trials. Research on NDSTs, however, may provide empirical data showing how much improvement is realized by specific versus non-specific factors. Studies directly comparing NDST with other psychotherapies can give an indication what the contribution of the specific techniques of these other psychotherapies is, compared with the nonspecific elements of NDST, which are common to all therapies. Furthermore, studies comparing NDST with no-treatment control conditions can provide an indication regarding the contribution of non-specific treatment elements over and above extra-therapeutic factors.

We decided, therefore, to conduct a meta-analysis of randomized trials examining the efficacy of NDST when compared to control conditions and to other psychotherapies in the treatment of depression. We also aimed to make an estimate of the extent to which extra-therapeutic, non-specific, and specific factors accounted for improvement.