Question: is this a 2) strong advice, 1) weak advice 0) no advice?

Despite its striking popularity (for example, in Germany, Hypericum extract had a market share of 25% of all antidepressant prescriptions in 1997 and outsold fluoxetine by a factor of 4 (Müller, Kasper, 1997; Harrison, 1998) the prophylactic effect of the herbal drug has so far not been investigated systematically. 
user
This is no advice
assistant