By Anne RinaudoWednesday 22 Aug 2018Open House InterviewsHealth and WellbeingReading Time: 4 minutes
Listen: Professor Gordon Parker in conversation with Stephen O’Doherty.
In an editorial for the British Journal of Psychiatry, Professor Gordon Parker tackles the fake news about antidepressants. The public have been misled and confused by studies that show antidepressants were no more effective than placebos.
The trouble says Professor Parker, eminent psychiatrist and founder of the Black Dog Institute, is that the trials have thrown all types of depression into to the mix. Depression has many types and Professor Parker says we know biological depression or melancholia shows a 60 per cent response to medication.
We are asking the wrong question
Are antidepressants effective or ineffective? According to Professor Gordon Parker AO, a professor of psychiatry at UNSW and the founder of the Black Dog Institute, the answer is irrelevant—because we’re asking the wrong question. In a British Journal of Psychiatry editorial Professor Parker says the question is simplistic.
Professor Parker likens using an antidepressant to treat all types of depression as equivalent to using a Ventolin inhaler to treat all types of lung conditions, regardless of whether a patient has asthma, where an inhaler may be effective, or pneumonia or a pulmonary embolus, where an inhaler would be ineffective and an entirely different treatment might be required.
Antidepressants do work
“For patients with depression, if you narrow down to those who have a biologically-based depressive sub-type, the antidepressants are distinctly effective,”
In the British Journal of Psychiatry, Parker challenges the findings of several studies that analysed the outcomes of multiple clinical trials of antidepressants. Collectively, these trials spanned hundreds of thousands of patients who received either antidepressants or placebos to treat a diagnosis of major depression.
Like using a Ventolin to treat all types of lung conditions.
The aggregated trial data were interpreted in the earlier studies as indicating that antidepressants were no more effective than placebos, leading to widespread public confusion about the validity of these drugs, while the most recent analysis argued for their effectiveness.
For the biologically-based depressive sub-type, antidepressants are effective.
An umbrella term
The problem, Parker argues, is that trialling antidepressants against a target condition of major depression produces, if not guarantees, flawed results. ‘Major depression’ is an umbrella term that refers to a range of depressive illnesses with varying causes, trajectories and treatment responses, rather than to a single condition.
“The conclusions that these studies have drawn are, in a sense, beside the point,” Parker says.
Different types of depression
“Basically, the target diagnosis of major depression captures multiple types of depressions—some biological, some psychological, some social—and not all would be expected to respond to medication.
“By bundling those with depression due to social and psychological causes in with the biological conditions, the signal benefits of antidepressant medication are swamped and effectively lost.”
Widespread public confusion about the validity of antidepressants.
Biological depression responds well
“For example, biological depression or melancholia shows a 60 per cent response to medication, compared to only a 10 per cent response to placebo. If, however, you include other depressive disorders with no primary biological basis—as occurs, if not dominates, in most studies—antidepressants appear to be ineffective.”
Trial results skewed
Parker’s editorial also raises serious questions about the design of antidepressant clinical trials, in which patients with serious conditions—such as suicidal ideation, drug and alcohol problems or personality disorders—are ruled out in favour of those with mild symptoms.
Despite meeting the major depression criteria, these low-acuity participants are highly likely to go into spontaneous remission or to respond to placebos, thereby skewing the trial results and subsequent analyses of a drug’s efficacy.
When are they effective?
“This approach doesn’t respect the real world, where there are multiple types of depressive conditions,” Parker says.
“It should not be a simplistic question—are antidepressants effective or ineffective? No treatment should be tested as if it has universal application for multiple differing depressive disorders.”
“It’s all about saying, what are the circumstances in which they’re effective, and when are they irrelevant?”
Not a good criteria for drug trials
In the article Professor Parker says, “Although most branches of medicine have refined their diagnostic subgroups over time (for instance ‘unpacking’ hepatitis or diabetes and not treating either as a uniform entity), the reifying of major depression as a diagnostic entity used for randomised controlled trials has moved psychiatry in the other direction. Such an outmoded approach advances a Procrustean model whereby the treatment received by those with major depression is determined principally by the background training or discipline of the practitioner.”
There are multiple types of depressive conditions
Patients made to fit a nonspecific diagnosis
“Thus, those with the diagnosis of major depression are likely to receive an antidepressant from a medical practitioner, cognitive–behavioural therapy from a psychologist and counselling from a counsellor – with the patient being ‘fitted’ to the nonspecific diagnosis rather than the treatment being fitted to a more precisely defined depressive subtype (i.e. psychotic or melancholic depression or a set of non-melancholic conditions reflecting acute and/or chronic stressors and predisposing personality styles).”
The editorial was published on August 1 in The British Journal of Psychiatry, Volume 213/Issue 2 the full research article is available here:
To listen to the podcast of this conversation click the red play button at the top of the page, or you can subscribe to Open House podcasts in iTunes and they will appear in your feed.