I suppose that depends on whom you talk to. I've talked people who've said they were given it as kids, and it made them very focused and attentive, and able and willing to learn what they were being taught. It doesn't just sedate them.
I don't believe "shared thoughts" will ever work.
One thing that's already been developed is the ability to use thoughts to control the movement of a cursor on a screen (via EEG technology, mostly), and progress is being made on more complicated operations. And if thoughts can be used to electronically influence the outside world, how long before the reverse can be true? How long before some form of stimulation can directly engender thoughts within a person's mind?
using thoughts and using re-routed motor nerve impulses or electro-encephalographic modulations are not the same thing.
there will have to be one hella MODEM for two brains to be able to directly communicate as if they were one brain with one united conscious synthesis.
As it seems quite possible that a substantially different MODEM would be required for each such link, I don't see tech cracking this nut.
any lesser communication would be nothing more or less than a novel source of stimulus or data for the mind to integrate into the individual conscious synthesis.