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General

Despite at times being courageous in taking a sceptical approach to the evidence, there are still serious problems and biases.

2.6.4 Pharmacological treatments

Do people really still believe that the mechanism of action of antidepressants is ability to block synaptic reuptake of monoamines? Surely it is better seen as a theory which has outrun its usefulness. It is clearly at least too simplistic. Most psychopharmacologists have given it up - it is about time clinicians did as well, so that the pharmaceutical industry cannot quote them in defence of yet more me-too drugs.

2.6.5 Psychological treatments

The reference to Fonagy (2003) is idiosyncratic and merely his opinion. Surely the reason that there are so many psychological therapies for depression is that it is common and there is a natural tendency to prefer short-term treatments over psychoanalysis.

2.6.7 Stepped care

The arbitrary nature of the steps in the model may need emphasising - in practice there is much more overlap eg. should mental health specialists only treat resistant and recurrent depression? Can primary care really cope with all moderate and severe depression? There is a need for at least some flexibility in the model and this could be emphasised to avoid rigid overinterpretation. WHO has produced useful guidelines about the balance between primary and secondary care - should these be mentioned?.

3.4.3.1 Assessing statistically significant summary statistics

The arbitrary nature of the definition of clinical significance may need to be emphasised, unless more explanation can be given of the reason for choosing RR<0.8. Such a definition is not used elsewhere in the literature, as far as we know. The difference between mean change scores (active treatment versus control) is probably the most reliable method of assessing the clinical significance of active effects (see below). It may need to be emphasised that measures of mean endpoint and mean change scores are usually made on the same or similar data - if the report wishes to continue with such a definition of clinical significance it needs at least to clarify why one method should be regarded as producing clinically significant results whereas another does not.

6.1.4 Use of RCTs in psychotherapy

Although the report mentions the bias in drug trials through unblinding, no mention is made of the fact that psychotherapy trials cannot strictly speaking be conducted double-blind. To provide a balance in the discussion between the data on pharmacotherapy and psychotherapy, there needs to be information about the problem of adequacy of control groups in psychotherapy trials. This also applies to trials of other treatments, such as exercise, discussed in section 5. Psychotherapy trials may well be as biased as drug trials.

6.7 Psychodynamic psychotherapy

Some mention should be made of the long-term nature of psychotherapy. Besides making it difficult to conduct clinical trials over a long period of time, long-term treatment may have more lasting benefits. There does need to be some counteracting of the tendency towards evidence reinforcing short-termism in treatment. Although such short-term effects are easier to measure, they are at least considerably compounded by placebo effects. Long-term psychotherapy is not necessarily ineffective just because it is difficult to measure its effects.

7.3 Limitations of the literature: problems with RCTs in pharmacology

Two components of recovery in placebo conditions are mentioned: spontaneous recovery and the effect of supportive care. This attribution of the placebo effect to supportive care is without empirical foundation. It could also be due to the self-confirming effects of expectancy on experience, classical conditioning, or other psychological mechanisms (see Kirsch, 1997,¹ for a review of data pertaining to these mechanisms). Placebo effects have been found without supportive care. In contrast, conditioning and expectancy effects have been well demonstrated as factors in placebo responding. There are indeed two components of improvement in placebo conditions, and one of them is correctly labeled "spontaneous recovery." The other should be labeled the placebo effect, without the attempt to deal with the tricky issue of the mechanism behind the placebo effect. The placebo effect is the placebo response minus changes due to spontaneous recovery, regression to the mean, etc.

2.6.3 Non-specific effects of treatment and the placebo

Why is it likely that with greater definition of subgroups that benefit over placebo may well be demonstrable? Isn't it just as unlikely? There is clearly a danger in searching for significance in subgroups when the main analysis in not significant.

7.7.3 Evidence statements in review of SSRIs versus placebos

Perhaps the most serious problem is the reliance on treatment response (a 50% reduction in symptoms) as a primary measure of outcome. Response rates are misleading, especially when the criterion for response is close to the mean improvement rate (as it generally is) (Kirsch, in press)². The main point is that a seemingly large difference in response rates (e.g., 50% versus 35%) can be entirely due to clinically insignificant differences between drug and placebo responses (e.g., one point the Hamilton depression scale). To quote from Kirsch (in press):

The other issue is severity. See comment on 7.7.1 - it may be well be misleading to rely on a few studies, mostly with outpatients, that have shown that the difference in response to antidepressants and placebo is greatest in people who have the most severe depression. Studies of people in hospital find smaller differences between antidepressants and placebo than do the outpatient studies.³ Indeed one study of inpatients showed that response to antidepressants was greatest in the least severely ill.⁴ The prognosis for hospital treated depression is also very poor, with studies finding that more than half of adults and an even higher proportion of older people have not recovered several years later.

7.2.2 Dose of antidepressant treatment

Evidence of a dose/response relation with tricyclics is mentioned, but no mention is made of the absence of this relation with SSRIs.

7.4 The placebo response

The increasing response to drug and placebo over the years could also be due (at least in part) to the coverage of antidepressants in the literature leading people to have greater faith in them (and thereby enhancing the placebo component of treatment). In any case, the hypothesis that it is due to "an increasing tendency for RCTs to be carried out with people with mild disorders" is contradicted by data in the Walsh et al. study (the correlation between initial level of depression and improvement in the placebo condition was .10). This could easily be checked with the data analysed in the NICE report. If the hypothesis is correct, there should be a high negative correlation between year of publication and baseline depression scores.

7.7.1 Introduction to review of SSRIs versus placebos

The report cites two studies as reporting evidence that the placebo response is greater with mild depression and that the drug-placebo difference is greater with increasing severity. There are also contrary data (see Figure 2 in Kirsch, Scoboria, and Moore,2002)⁵; To quote from that article:

The data presented in the NICE report also contradict the idea that the drug effect is greatest among the most severely depressed patients. Instead, in mean end-point or change scores, it shows some evidence of a nonlinear relation, with the size of drug/placebo differences "unlikely to be of clinical significance" in very severe, as well as moderate depression.

8.1.7 Recommendations for the use of individual drugs in the treatment of depression

If the recommendation about fluoxetine having fewer discontinuation symptoms is from Rosenbaum et al, it is important to emphasise that this study was funded by its manufacturers Eli Lilly.⁶ Surely this evidence at least needs to be replicated before being used as the basis for a recommendation.

8.3.4.11.1 Augmenting an antidepressant with another antidepressant

Evidence statements in 8.3.4.14 and 8.3.4.15 have been produced by combining very different trials. Nor do they seem very strong statements, yet 8.3.5.1.4 makes specific recommendations about adding mianserin to SSRIs and mirtazapine to SSRIs, venlafaxine and buproprion. Surely the evidence for these specific recommendations needs to be replicated, or specific analyses need to be shown in the report, rather than using an evidence statement from pooled data. Probably there needs to be more caution about recommending the combination of antidepressants in itself. Why not use the expression of the need for caution, as in the pindolol recommendation?

7.1 Introduction re antidepressant discontinuation reactions

It may be misleading to suggest that discontinuation symptoms are usually mild and generally resolve rapidly with reinstatement or within a few days to weeks without reinstatement. A significant number of people do experience discontinuation symptoms of such severity that it seems to make it difficult to stop. Not only abrupt but also gradual withdrawal may be associated with potentially serious adverse effects. Although the pattern may be different from relapse, doctors often misinterpret discontinuation symptoms as relapse, and there may be no defining feature that can differentiate.

8.2.8.1 Introduction to antidepressant discontinuation reactions

Is it clear what the nature of antidepressant discontinuation reactions are? How well accepted is the concept of "receptor rebound" in this context? How are discontinuation symptoms related to habituation ie. are discontinuation symptoms a reflection of psychological dependence rather than receptor rebound as such? Is there really enough controlled trial data over a longer period to suggest that onset is usually within 5 days?

2.8 Patient preference, information, consent and mutual support

There needs to be discussion with patients about the evidence for efficacy of treatments, including medication, and specific discussion of the risks of discontinuation reactions at the time of consent. 2.8.1.2 is not specific enough on these points. There needs to be a more direct link with 8.2.8.6.2 and 8.2.8.6.3

8.2.10.2 Suicidality and antidepressants

There is surprisingly no discussion of whether SSRIs cause behavioural disorders, including suicidal behaviour.

2.6.2.6 Inpatient treatment should be considered for people with depression where the patient is at significant risk of suicide

Why C, not GPP?

9.2 Key economic issues

Although mentioned elsewhere in the report, a key issue is the rising cost of antidepressants and the need to control pharmaceutical expenditure and company profit.

1.2.2 For whom is this guideline intended?

Is it for over 17s or over 18s? Ambiguity needs to be made clear

1.2.3 Specific aims of this guideline

Misprints - guideline is for depression, not eating disorder