Earlier quoted context omitted.
This is not entirely true. Tramadol are often given in doses of 3x50 mg a day for pain relief. To a user with no tolerance, the most common lowest dose, i.e. 1x50 mg is certainly more than enough to give a euphoric feeling, ability to concentrate, stress relief and a whole range of other effects. Effects obviously can't be compared to "real" opiates, where the effect is much stronger and have more of a sedative effec…
The article, and Zunger's G+ discussion as mentioned below, clearly established that they were taking very high doses.
That might be, but that's not relevant to the point of what dosage is necessary for a psychological effect.