Effects of maintenance amitriptyline and psychotherapy on symptoms of depression

Control interventions in randomised trials among people with mental health disorders

BACKGROUND

Control interventions in randomised trials provide a frame of reference for the experimental interventions and enable estimations of causality. In the case of randomised trials assessing patients with mental health disorders, many different control interventions are used, and the choice of control intervention may have considerable impact on the estimated effects of the treatments being evaluated.

OBJECTIVES

To assess the benefits and harms of typical control interventions in randomised trials with patients with mental health disorders. The difference in effects between control interventions translates directly to the impact a control group has on the estimated effect of an experimental intervention. We aimed primarily to assess the difference in effects between (i) wait-list versus no-treatment, (ii) usual care versus wait-list or no-treatment, and (iii) placebo interventions (all placebo interventions combined or psychological, pharmacological, and physical placebos individually) versus wait-list or no-treatment. Wait-list patients are offered the experimental intervention by the researchers after the trial has been finalised if it offers more benefits than harms, while no-treatment participants are not offered the experimental intervention by the researchers.

SEARCH METHODS

In March 2018, we searched MEDLINE, PsycInfo, Embase, CENTRAL, and seven other databases and six trials registers.

SELECTION CRITERIA

We included randomised trials assessing patients with a mental health disorder that compared wait-list, usual care, or placebo interventions with wait-list or no-treatment .

DATA COLLECTION AND ANALYSIS

Titles, abstracts, and full texts were reviewed for eligibility. Review authors independently extracted data and assessed risk of bias using Cochrane's risk of bias tool. GRADE was used to assess the quality of the evidence. We contacted researchers working in the field to ask for data from additional published and unpublished trials. A pre-planned decision hierarchy was used to select one benefit and one harm outcome from each trial. For the assessment of benefits, we summarised continuous data as standardised mean differences (SMDs) and dichotomous data as risk ratios (RRs). We used risk differences (RDs) for the assessment of adverse events. We used random-effects models for all statistical analyses. We used subgroup analysis to explore potential causes for heterogeneity (e.g. type of placebo) and sensitivity analyses to explore the robustness of the primary analyses (e.g. fixed-effect model).

MAIN RESULTS

We included 96 randomised trials (4200 participants), ranging from 8 to 393 participants in each trial. 83 trials (3614 participants) provided usable data. The trials included 15 different mental health disorders, the most common being anxiety (25 trials), depression (16 trials), and sleep-wake disorders (11 trials). All 96 trials were assessed as high risk of bias partly because of the inability to blind participants and personnel in trials with two control interventions. The quality of evidence was rated low to very low, mostly due to risk of bias, imprecision in estimates, and heterogeneity. Only one trial compared wait-list versus no-treatment directly but the authors were not able to provide us with any usable data on the comparison. Five trials compared usual care versus wait-list or no-treatment and found a SMD -0.33 (95% CI -0.83 to 0.16, I² = 86%, 523 participants) on benefits. The difference between all placebo interventions combined versus wait-list or no-treatment was SMD -0.37 (95% CI -0.49 to -0.25, I² = 41%, 65 trials, 2446 participants) on benefits. There was evidence of some asymmetry in the funnel plot (Egger's test P value of 0.087). Almost all the trials were small. Subgroup analysis found a moderate effect in favour of psychological placebos SMD -0.49 (95% CI -0.64 to -0.30; I² = 53%, 39 trials, 1656 participants). The effect of pharmacological placebos versus wait-list or no-treatment on benefits was SMD -0.14 (95% CI -0.39 to 0.11, 9 trials, 279 participants) and the effect of physical placebos was SMD -0.21 (95% CI -0.35 to -0.08, I² = 0%, 17 trials, 896 participants). We found large variations in effect sizes in the psychological and pharmacological placebo comparisons. For specific mental health disorders, we found significant differences in favour of all placebos for sleep-wake disorders, major depressive disorder, and anxiety disorders, but the analyses were imprecise due to sparse data. We found no significant differences in harms for any of the comparisons but the analyses suffered from sparse data. When using a fixed-effect model in a sensitivity analysis on the comparison for usual care versus wait-list and no-treatment, the results were significant with an SMD of -0.46 (95 % CI -0.64 to -0.28). We reported an alternative risk of bias model where we excluded the blinding domains seeing how issues with blinding may be seen as part of the review investigation itself. However, this did not markedly change the overall risk of bias profile as most of the trials still included one or more unclear bias domains.

AUTHORS' CONCLUSIONS

We found marked variations in effects between placebo versus no-treatment and wait-list and between subtypes of placebo with the same comparisons. Almost all the trials were small with considerable methodological and clinical variability in factors such as mental health population, contents of the included control interventions, and outcome domains. All trials were assessed as high risk of bias and the evidence quality was low to very low. When researchers decide to use placebos or usual care control interventions in trials with people with mental health disorders it will often lead to lower estimated effects of the experimental intervention than when using wait-list or no-treatment controls. The choice of a control intervention therefore has considerable impact on how effective a mental health treatment appears to be. Methodological guideline development is needed to reach a consensus on future standards for the design and reporting of control interventions in mental health intervention research.

An analysis of psychotherapy versus placebo studies

Smith, Glass, and Miller (1980) have reported a meta-analysis of over 500 studies comparing some form of psychological therapy with a control condition. They report that when averaged over all dependent measures of outcome, psychological therapy is. 85 standard deviations better than the control treatment. We examined the subset of studies included in the Smith et al. metaanalysis that contained a psychotherapy and a placebo treatment. The median of the mean effect sizes for these 32 studies was. 15. There was a nonsignificant inverse relationship between mean outcome and the following: sample size, duration of therapy, use of measures of outcome other than undisguised self-report, measurement of outcome at follow-up, and use of real patients rather than subjects solicited for the purposes of participation in a research study. A qualitative analysis of the studies in terms of the type of patient involved indicates that those using psychiatric outpatients had essentially zero effect sizes and that none using psychiatric inpaticnts provide convincing evidence for psychotherapeutic effectiveness. The onty studies clearly demonstrating significant effects of psychotherapy were the ones that did not use real patients. For the most part, these studies involved small samples of subjects and brief treatments, occasionally described in quasibeliavioristic language. It was concluded that for real patients there is no evidence that the benefits of psychotherapy are greater than those of placebo treatment.

Depression: The predisposing influence of stress

Aversive experiences have been thought to provoke or exacerbate clinical depression. The present review provides a brief survey of the stress-depression literature and suggests that the effects of stressful experiences on affective state may be related to depletion of several neurotransmitters, including norepinephrine, dopamine, and serotonin. A major element in determining the neurochemical changes is the organism's ability to cope with the aversive stimuli through behavioral means. Aversive experiences give rise to behavioral attempts to cope with the stressor, coupled with increased utilization and synthesis of brain amines to contend with environmental demands. When behavioral coping is possible, neurochemical systems are not overly taxed, and behavioral pathology will not ensue. However, when there can be no behavioral control over the stressful stimuli, or when the aversive experience is perceived as uncontrollable, increased emphasis is placed on coping through endogenous neurochemical mechanisms. Amine utilization increases appreciably and may exceed synthesis, resulting in a net reduction of amine stores, which in turn promotes or exacerbates affective disorder. The processes governing the depletions may be subject to sensitization or conditioning, such that exposure to traumatic experiences may have long-term repercussions when the organism subsequently encounters related stressful stimuli. With continued uncontrollable stimulation, adaptation occurs in the form of increased activity of synthetic enzymes, and levels of amines approach basal values. It is suggested that either the initial amine depletion provoked by aversive experiences or a dysfunction of the adaptive processes, resulting in persistent amine depletion, contributes to behavioral depression. Aside from the contribution of behavioral coping, several organismic, experiential, and environmental variables will influence the effects of aversive experiences on neurochemical activity, and may thus influence vulnerability to depression.

Placebo interventions for all clinical conditions

BACKGROUND

Placebo interventions are often claimed to substantially improve patient-reported and observer-reported outcomes in many clinical conditions, but most reports on effects of placebos are based on studies that have not randomised patients to placebo or no treatment. Two previous versions of this review from 2001 and 2004 found that placebo interventions in general did not have clinically important effects, but that there were possible beneficial effects on patient-reported outcomes, especially pain. Since then several relevant trials have been published.

OBJECTIVES

Our primary aims were to assess the effect of placebo interventions in general across all clinical conditions, and to investigate the effects of placebo interventions on specific clinical conditions. Our secondary aims were to assess whether the effect of placebo treatments differed for patient-reported and observer-reported outcomes, and to explore other reasons for variations in effect.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library Issue 4, 2007), MEDLINE (1966 to March 2008), EMBASE (1980 to March 2008), PsycINFO (1887 to March 2008) and Biological Abstracts (1986 to March 2008). We contacted experts on placebo research, and read references in the included trials.

SELECTION CRITERIA

We included randomised placebo trials with a no-treatment control group investigating any health problem.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We contacted study authors for additional information. Trials with binary data were summarised using relative risk (a value of less than 1 indicates a beneficial effect of placebo), and trials with continuous outcomes were summarised using standardised mean difference (a negative value indicates a beneficial effect of placebo).

MAIN RESULTS

Outcome data were available in 202 out of 234 included trials, investigating 60 clinical conditions. We regarded the risk of bias as low in only 16 trials (8%), five of which had binary outcomes.In 44 studies with binary outcomes (6041 patients), there was moderate heterogeneity (P < 0.001; I(2) 45%) but no clear difference in effects between small and large trials (symmetrical funnel plot). The overall pooled effect of placebo was a relative risk of 0.93 (95% confidence interval (CI) 0.88 to 0.99). The pooled relative risk for patient-reported outcomes was 0.93 (95% CI 0.86 to 1.00) and for observer-reported outcomes 0.93 (95% CI 0.85 to 1.02). We found no statistically significant effect of placebo interventions in four clinical conditions that had been investigated in three trials or more: pain, nausea, smoking, and depression, but confidence intervals were wide. The effect on pain varied considerably, even among trials with low risk of bias.In 158 trials with continuous outcomes (10,525 patients), there was moderate heterogeneity (P < 0.001; I(2) 42%), and considerable variation in effects between small and large trials (asymmetrical funnel plot). It is therefore a questionable procedure to pool all the trials, and we did so mainly as a basis for exploring causes for heterogeneity. We found an overall effect of placebo treatments, standardised mean difference (SMD) -0.23 (95% CI -0.28 to -0.17). The SMD for patient-reported outcomes was -0.26 (95% CI -0.32 to -0.19), and for observer-reported outcomes, SMD -0.13 (95% CI -0.24 to -0.02). We found an effect on pain, SMD -0.28 (95% CI -0.36 to -0.19)); nausea, SMD -0.25 (-0.46 to -0.04)), asthma (-0.35 (-0.70 to -0.01)), and phobia (SMD -0.63 (95% CI -1.17 to -0.08)). The effect on pain was very variable, also among trials with low risk of bias. Four similarly-designed acupuncture trials conducted by an overlapping group of authors reported large effects (SMD -0.68 (-0.85 to -0.50)) whereas three other pain trials reported low or no effect (SMD -0.13 (-0.28 to 0.03)). The pooled effect on nausea was small, but consistent. The effects on phobia and asthma were very uncertain due to high risk of bias. There was no statistically significant effect of placebo interventions in the seven other clinical conditions investigated in three trials or more: smoking, dementia, depression, obesity, hypertension, insomnia and anxiety, but confidence intervals were wide.Meta-regression analyses showed that larger effects of placebo interventions were associated with physical placebo interventions (e.g. sham acupuncture), patient-involved outcomes (patient-reported outcomes and observer-reported outcomes involving patient cooperation), small trials, and trials with the explicit purpose of studying placebo. Larger effects of placebo were also found in trials that did not inform patients about the possible placebo intervention.

AUTHORS' CONCLUSIONS

We did not find that placebo interventions have important clinical effects in general. However, in certain settings placebo interventions can influence patient-reported outcomes, especially pain and nausea, though it is difficult to distinguish patient-reported effects of placebo from biased reporting. The effect on pain varied, even among trials with low risk of bias, from negligible to clinically important. Variations in the effect of placebo were partly explained by variations in how trials were conducted and how patients were informed.

Placebo interventions for all clinical conditions

BACKGROUND

Placebo interventions are often claimed to improve patient-reported and observer-reported outcomes, but this belief is not based on evidence from randomised trials that compare placebo with no treatment.

OBJECTIVES

To assess the effect of placebo interventions.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2002), MEDLINE (1966 to 2002), EMBASE (1980 to 2002), Biological Abstracts (1986 to 2002), and PsycLIT (1887 to 2002). We contacted experts on placebo research, and read references in the included trials.

SELECTION CRITERIA

We included randomised placebo trials with a no-treatment control group investigating any health problem.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. We contacted study authors for additional information.

MAIN RESULTS

Outcome data were available in 156 out of 182 included trials, investigating 46 clinical conditions. We found no statistically significant pooled effect of placebo in 38 studies with binary outcomes (4284 patients), relative risk 0.95 (95% confidence interval (CI) 0.89 to 1.01). The pooled relative risk for patient-reported outcomes was 0.95 (95% CI 0.88 to 1.03) and for observer-reported outcomes 0.91 (95% CI 0.81 to 1.03). There was heterogeneity (P=0.01) but the funnel plot was symmetrical. There was no statistically significant effect of placebo interventions in the four clinical conditions investigated in three trials or more: pain, nausea, smoking, and depression, but confidence intervals were wide. We found an overall effect of placebo treatments in 118 trials with continuous outcomes (7453 patients), standardised mean difference (SMD) -0.24 (95% CI -0.31 to -0.17). The SMD for patient-reported outcomes was -0.30 (95% CI -0.38 to -0.21), whereas no statistically significant effect was found for observer-reported outcomes, SMD -0.10 (95% CI -0.20 to -0.01). There was heterogeneity (P<0.001) and large variability in funnel plot results even for big trials. There was an apparent effect of placebo interventions on pain (SMD -0.25 (95% CI -0.35 to-0.16)), and phobia (SMD -0.63 (95% CI -1.17 to -0.08)); but also a substantial risk of bias. There was no statistically significant effect of placebo interventions in eight other clinical conditions investigated in three trials or more: nausea, smoking, depression, overweight, asthma, hypertension, insomnia and anxiety, but confidence intervals were wide.

REVIEWERS' CONCLUSIONS

There was no evidence that placebo interventions in general have clinically important effects. A possible small effect on continuous patient-reported outcomes, especially pain, could not be clearly distinguished from bias.

Placebo treatment versus no treatment

BACKGROUND

Placebo interventions are often believed to improve patient reported and observer reported outcomes, but this belief is not based on evidence from randomised trials that compare placebo with no treatment.

OBJECTIVES

To assess the effect of placebo interventions.

SEARCH STRATEGY

We searched the Cochrane Controlled Trials Register (The Cochrane Library, issue 3, 1998), MEDLINE (Jan 1966 to Dec 1998), EMBASE (Jan 1980 to Dec 1998), Biological Abstracts (Jan 1986 to Dec 1998), PsycLIT (Jan 1887 to Dec 1998). Experts on placebo research were contacted and references in the included trials were read.

SELECTION CRITERIA

Randomised placebo trials with a no-treatment control group investigating any health problem were included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Outcome data were available in 114 out of 130 included trials, investigating 40 clinical conditions. Outcomes were binary in 32 trials (3795 patients) and continuous in 82 (4730 patients). We found no statistically significant pooled effect of placebo in studies with binary outcomes, relative risk 0.95 (95 per cent confidence interval 0.88 to 1.02). The pooled relative risk for subjective (patient reported) outcomes was 0.95 (0.86 to 1.05) and for objective (observer reported) outcomes 0.91 (0.80 to 1.04). There was statistically significant heterogeneity (P < 0.03), but no evidence of sample size bias (P = 0.56). We found an overall positive effect of placebo treatments in trials with continuous outcomes, standardised mean difference -0.28 (95 per cent confidence interval -0.38 to -0.19). The standardised mean difference for subjective outcomes was -0.36 (-0.47 to -0.25), whereas no statistically significant effect was found for objective outcomes, standardised mean difference -0.12 (-0.27 to 0.03). There was statistically significant heterogeneity (P < 0.001), and evidence of sample size bias (P = 0.05). There was no statistically significant effect of placebo interventions in eight out of nine clinical conditions investigated in three trials or more (nausea, relapse in prevention of smoking and depression, overweight, asthma, hypertension, insomnia and anxiety), but confidence intervals were wide. There was a modest apparent analgesic effect of placebo interventions, standardised mean difference -0.27 (-0.40 to -0.15), but also a substantial risk of bias.

REVIEWER'S CONCLUSIONS

There was no evidence that placebo interventions in general have clinically important effects. A possible moderate effect on subjective continuous outcomes, especially pain, could not be clearly distinguished from bias.

Continuation and maintenance therapy in depression

This paper reviews longer term treatment for unipolar depression. Antidepressant continuation for prevention of early relapse has been routine for many years. Recent evidence supports a longer period of 9 months to 1 year after remission. Antidepressants are also effective in maintenance treatment for recurrent depression, and are indicated where there is clear risk of further episodes. Antidepressant withdrawal after continuation and maintenance should always be gradual, over a minimum of 3 months and longer after longer maintenance periods, to avoid withdrawal symptoms or rebound relapse. Trials of interpersonal therapy in the prevention of recurrence show some benefit, but effects are weaker than those of drug and additional benefit in combination is limited. There is better evidence for effects of cognitive therapy in preventing relapse and an emerging indication for its addition to antidepressants, particularly where residual symptoms are present.

Statistics and the nature of depression

A critical examination is made of the role that statistical methods have played in the understanding of depression. The development of instruments for measuring depression is illustrated by reference to the Beck Depression Inventory and the Hamilton Rating Scale. The controversy over the existence of one or two types of depression is examined from the perspective of the statistical tools used. Some of the problems in studies of the heritability of depression are outlined. The development of clinical trials of depression is examined, with particular reference to ECT and maintenance therapy, and the role of meta-analysis is discussed.

Continuation and maintenance therapy with antidepressive agents. Meta-analysis of research

The purpose of this study was to ascertain the clinical benefits of long-term antidepressant drug treatment in patients with recurrent major depression. Bibliographic reviews of four textbooks and five review articles, literature searches using MEDLINE (1977-1987) and EXCERPTA MEDICA (1974-1987), hand-searching of the bibliographies of identified papers, and a private set were used for data identification. The most informative, definitive research report was selected using explicit criteria for evaluating study design and quality, of each described, randomized, controlled, double-blind trial of long-term antidepressant agent treatment. The trials were started at a specified period after recovery from an affective episode, in patients with major depression. Of the fifty-five originally identified articles, nine were selected that specifically addressed this purpose. The basic data were extracted in the form of 2 x 2 tables comparing the number of patients with an affective relapse to those remaining well and meta-analysed. Six of the selected trials addressed continuation and three addressed maintenance therapy. In two trials of continuation and in one trial of maintenance treatment, antidepressants were significantly more active than a placebo. In none of the trials were antidepressants inferior to a placebo. Continuation therapy with antidepressants (amitriptyline and imipramine) is effective. There are insufficient data to allow any conclusions about the efficacy of maintenance therapy with antidepressants, long-term treatment with antidepressants relative to that with lithium carbonate, or long-term antidepressant treatment in patients with chronic depression.

Combination tricyclic antidepressant and lithium maintenance medication in unipolar and bipolar depressed patients

In a small study of up to 3 years' duration comparison of the value of amitriptyline alone versus amitriptyline + lithium in unipolar cases (27 patients) and of that of lithium alone versus amitriptyline + lithium in bipolar cases (13 patients) showed no advantage for the combination treatments in terms of efficacy in reducing depressive relapses. There was no effect of treatment, developing depression or developing hypothyroidism upon the psychological tests which were conducted during this prolonged study. Observer and self ratings detected an increase in depression before relapse was clearly present, but of the various psychological assessments conducted only arousal showed changes in association with developing and definite relapse. The prescription of lithium but not amitriptyline + lithium or amitriptyline alone was associated with significant increases in blood pressure.

Continuation and maintenance therapy with antidepressive agents. An overview of research

The literature was reviewed in order to ascertain the clinical benefits of long-term antidepressant drug treatment in recurrent major depression. Articles describing randomized, controlled, double-blind trials of long-term antidepressant drug treatment, starting at a specified period after recovery from an affective episode, in patients with major depression, were identified and reviewed. The authors describe, evaluate and comment on the design and quality of over 25 identified studies, 18 studies of continuation therapy and 7 of maintenance treatment. The methodological problems which are encountered in this type of research and the sources of bias which invalidate study results, are dealt with systematically. On the basis of this survey, some treatment guidelines and suggestions for future research are given.

Prophylactic medication for unipolar depressive illness: the place of lithium carbonate in combination with antidepressant medication

A meta-analysis of the controlled clinical trials comparing the efficacy of combined lithium-imipramine therapy with each drug alone in the prevention of relapse in patients with unipolar depressive illness shows the combination to be superior to lithium alone (for any relapse, p less than 0.05; for specifically depressive relapse, p less than 0.025) and imipramine alone (for any relapse, p less than 0.025; for specifically depressive relapse, p less than 0.05). The issue of statistical power in studies of this kind is discussed. A single case of unipolar depressive illness is described, in which combined lithium-tranylcypromine therapy was superior to either drug alone. A combination of lithium and an antidepressant should be considered for any patient suffering from this condition who fails to remain well on either drug alone.

Treatment of depression. The relevance of research for clinical practice

My aim in this lecture is to review a wide range of published studies on the treatment of depression. I want to look at these with one major clinical question in mind: given the range of treatments available, which treatment should be chosen for which patient? In July 1985 a report, published as a special supplement to the American Journal of Psychiatry, called for more research on this topic:

“As the number and diversity of the effective drugs and psychosocial interventions expand, clinicians will increasingly want objective, reliable criteria with which to match the patient to the optimal treatment modality and to monitor the response.” (Institute of Medicine, 1985)

Tricyclic maintenance therapy in unipolar depression

The risk of recurrence of depression must be balanced against the problems and risks of maintenance therapy. The goal of maintenance therapy is to prevent new episodes of depression. A review of the literature reveals that the existing data does not provide sufficient evidence to demonstrate the usefulness of tricyclic maintenance therapy. Nonetheless, it would be premature to conclude that this type of treatment is not useful. Further studies of maintenance therapy are indicated and should include a continuation period of at least 16 weeks during which patients are symptom free (that is, Global Assessment Scale 71 or more). In the interim, each patient should be evaluated individually to determine the optimum duration of treatment.

Antidepressants: Their efficacy and place in therapy

This paper reviews and relates to the wider published literature a series of studies directed to the broad question of which antidepressant treatment is required for which kind of depressed patient. Adequate methodology requires comparisons with placebo and other active drugs, rather than analysis of single treatment groups, so that the magnitude of therapeutic benefit due to specific drug effects can be measured. Reasonably firm conclusions are now possible. Electroconvulsive therapy (ECT) is most effective in severely depressed patients, particularly those with delusions or retardation, and is superior to antidepressant drugs in such patients. Monoamine oxidase (MAO) inhibitors show some selectivity towards patients with anxiety or reversed functional shift symptoms, but this selectivity appears quite limited, and tricyclic antidepressants also benefit such patients. The possibility of other factors, not well reflected in clinical features, which determine consistency of response requires further investigation. Recent evidence has led to re-evaluation of the earlier view that tricyclic antidepressants were specifically indicated in endogenous depressions. They appear to be broad-spectrum antidepressants, with efficacy extending more widely into neurotic disorders, mixed anxiety depressions, anxiety disorders, and into the relatively mild non-endogenous depressions of general practice.

Psychotherapy research: physiological measures and intrapsychic events

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