Brief Psychotherapies for Depression: Current Status

Jan Scott; Edward Watkins

Disclosures

Curr Opin Psychiatry. 2004;17(1) 

In This Article

Mediators and Moderators of Brief Psychotherapy

Beyond determining the efficacy and effectiveness of therapies, it is important to determine the mechanisms, moderators and predictors of response to psychotherapies. Finding the answers to questions such as 'how does therapy work?', 'what determines/predicts the effectiveness of therapy?', 'how do we target therapy more effectively?' is essential to developing better therapy and matching therapy to patients systematically rather than by trial-and-error. We first review evidence pertaining to non-specific mediators and predictors, that is, those factors common across psychotherapies, before turning to more specific processes, such as cognitive mechanisms in cognitive therapy.

The relationship between the therapist and patient is clearly an important factor in the process and outcome of therapy. Previous research has shown that both the patient's contribution to the alliance, (e.g. patient's openness, honesty, active engagement and agreement with therapist as rated on videotapes of therapy sessions), and the quality of therapeutic relationship as reported by patient, independently predict outcome for both cognitive therapy and IPT.[23,24] More recently, Meyer et al.[25] reanalysed these data and found that patients' pretreatment expectations of therapeutic effectiveness predicted their active engagement in therapy, which then led to greater improvement across cognitive therapy, IPT and ADM. Thus, the effects of patients' treatment expectancies on outcome were mediated by alliance ratings across all treatment conditions. It is important to note that only pretreatment expectancies were assessed; patients' expectancies after some experience of therapy may be an even stronger predictor of outcome.

A number of patient variables have been found to predict poor outcome.[26] Perfectionistic beliefs adversely influenced outcome for cognitive therapy, IPT, ADM and placebo, even when controlling for personality disorder features.[27] This effect is partially mediated by perfectionists' failure to develop such a strong therapeutic alliance.[28] Shahar et al.[27] also found that odd-eccentric and depressive personality features independently predicted poor outcome for all the brief treatments for depression.

Tang and DeRubeis[29] found that a significant minority of depressed patients undergoing cognitive therapy showed substantial symptom improvement in one between-session interval, rather than gradual and steady improvement over time. This rapid improvement, called 'sudden gains', accounted for over half of the total symptom improvement, usually occurred early in therapy and was associated with better long-term outcomes, with patients who experienced sudden gains significantly less depressed than other patients at 18-month follow-up. In cognitive therapy, sudden gains seemed to be preceded by critical sessions in which substantial cognitive changes occurred. However, the sudden gains effect has now been demonstrated in supportive-expressive psychotherapy for depression[30**] and in a range of psychotherapies across a range of disorders. Thus, the sudden gains effect appears to be a non-specific phenomenon of relevance to outcomes for a number of short-term psychotherapies.

In recent years, a number of studies have begun to indicate that changes in the way that depressed patients process depression-related information rather than changes in depressive thought content may be important in the mechanism of CBT. Teasdale et al.[31] previously found that cognitive therapy helps patients with residual depression, not by changing the content of their thinking but by changing the form of their thinking. In particular, cognitive therapy reduced an absolutist all-or-nothing thinking style, which, in turn, was found to mediate the effects of cognitive therapy on preventing relapse. Teasdale et al. suggested that this finding is consistent with the notion that cognitive therapy helps patients to acquire compensatory or metacognitive skills. This proposal is supported by Manber et al.[32] who found that improvements in a specific cognitive skill, 'situational analysis', during the first 6 weeks of therapy predicted level of depression at the end of treatment.

Teasdale and colleagues[33**] also examined a particular metacognitive skill called 'metacognitive awareness', defined as the ability to view thoughts as mental events in a wider context of awareness, rather than as expressions of reality. In a controlled study, metacognitive awareness for depressing memories from the 5 months before the assessment predicted the time to relapse for patients with residual depression. Furthermore, where cognitive therapy or mindfulness-based cognitive therapy, were effective in reducing relapse, these treatments also increased metacognitive awareness. Taken together, these studies indicate that CT may prevent relapse by shifting the mode of processing adopted by patients. However, these studies have exclusively focused on residual depression with relapse as the outcome measure. The generalizability of these findings to treating acute depression remains unresolved.

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