I've only seen such drugs ads in the US. Most other countries seem to realize that watching a 30 second ad is unlikely to make you more informed than a MD or PharmD.
It's not about being informed, it's - like all marketing - about being misinformed. And in this case, the intended effect is that the patient will pressure the doctor to prescribe them the drug they've seen on TV.
In most cases I might agree with you - but as a counterpoint I would posit a huge problem among the medical community: patient compliance with treatment. Sometimes health outcomes have nothing to do with the treatment itself, but rather the patient(s) are not likely to adhere strictly to the recommendations. [Source: my graduate school advisor was a health economist - but I'm sure there are studies out there to validate this.]
Something to keep in mind: not all drugs are bad. And even those that get a historical bad rap are ok in _moderation_ - some drugs are very helpful and necessary for certain conditions.
If drug ads and/or neuromarketing can improve patient outcomes by improving the likelihood that a patient complies with treatment, then is that all that bad?
"This shit will fuck you up six ways from Sunday but we make a ton of money off of it so ask your doctor..."