You must have heard it by now. Contrary to current belief, antidepressants work much faster what previously thought, in fact within hours of taking the drug. This is, according to BBC, what Oxford University researchers found. " Although patients may not notice the effects until months into the therapy, the team say they work subconsciously", writes  BBC Health reporter Michelle Roberts.

I have to say that I found this reference to subconscious work intriguing, given that of all Freudian concepts, the concept of the Unconscious mind is the one that is contested the most, both "scientifically" and philosophically (you can read some comments on the subject here). But this is not the reason I am posting this. What I was more interested in learning was how did they do it exactly, how did the researchers manage to observe the possible "subconscious" effects of a treatment?

I read, for example, lead researcher Psychiatrist Dr Catherine Harmer quoted as saying the following: "We found the antidepressants target the negative thoughts before the patient is aware of any change in feeling subjectively." Does this really mean that the researchers were able to measure changes in the negative thoughts of patients objectively and before the patients themselves knew of any changes?

I searched a bit and found the abstract of the original paper, "Effect of Acute Antidepressant Administration on Negative Affective Bias in Depressed Patients". It was revealing. This is how the researchers summarized their findings:

Depressed patients who received placebo showed reduced recognition of positive facial expressions, decreased speed in responding to positive self-relevant personality adjectives, and reduced memory for this positive information compared to healthy volunteers receiving placebo. However, this effect was reversed in patients who received a single dose of reboxetine, despite the absence of changes in subjective ratings of mood or anxiety.

Now it makes more sense, isn't it? Thought processes were measured in terms of response speeds to various visual and aural stimuli, and of recall rates of those stimuli, while mood and anxiety were measured via psychometric tests, most probably with the help of Likert scales.

Let me spell it out. The researchers did not really measure negative thoughts; they measured response speeds (in seconds) and recall rates (in percentages). And they assessed the participants' subjective feelings with the help of questionnaires.

Do you see where the pitfall is? The whole argument is a circular one.

• Response speeds (in seconds) and recall rates (in percentages) are believed to reflect thought processes.
• Why? Possibly because of previous research.
• What did previous research show? Possibly that higher response speeds to and recall rates of a specific stimulus indicate a more positive disposition towards this stimulus.
• How have we established this? Possibly with the help of questionnaires. In other words, questionnaires have helped us establish links between specific objective measurements and specific thought processes.
• Now we take these links for granted and try to explain why our objective measurements are not linked to the results of our questionnaires when our participants have taken reboxetine or something.
• The researchers' conclusion: Reboxetine affects thought processes well before the subjects can report any notable mood change with our questionnaires. Or, as the BBC has it, Antidepressants 'work instantly'.

Is this a sound argument?

I don't know, ask yourselves: is it?

(Hint: What do we know about the action of reboxetine and how have we assessed the psychical aspects of this action?)