Yes they do, but in a haphazard way. Normally the third eye opens naturally as the person engages in activities which send energy up the spine toward the occipital protuberance and into the brain. You can choose to stop at any time, rest, and try again. Psychedelics blast the third eye open but not in an integrated way. In the different centres of the body there are normal activity levels, deficiencies, and excesses. Psychedelics produce excess in the third eye, without doing the connective work to tie it to the other chakras. You also can't stop the process until the psychedelic experience is over, which means you have almost no control over what appears and whether or not you want to see it. You can alter the trip by changing your thought patterns but if what you're seeing is an externality like an entity, there's no way to close yourself down in order to stop the experience.
The other thing is, even if you're using psychs to explore psychic abilities, you have to do major grounding work and integration in between trips. If all you're doing is tripping over and over without any work in between, you're going to eventually have a psychotic break.
Third eye explorations are overrated. Psychic abilities are a manifestation on the spiritual path but aren't meant to be the end goal. If you have some talents then great, use them to gain better insight into the nature of reality. If you don't have those talents or it's not part of your path, then don't go seeking them. People who want psychic powers really don't know what they're asking for. A fully opened and realized third eye will change your life forever, and you can't put that geni back into the bottle. For the rest of your life you won't just be exposed to nice things, but dark things, and things about society that you can't unsee. On another level, psychic abilities for their own sake aren't meant to be their own playground and treating them as such will trap you in la la land where you won't be able to fulfill your life's mission. People who use psychs to develope psychic powers are usually extremely ungrounded and without care they can become useless to themselves. They become an endless distraction. Be warned.
And no, psychic abilities aren't part of the regular senses. The regular senses are in the dense physical body. The third eye and what it sees are beyond the 3D. Everything of course integrates into the physical body (like the pineal gland as the receiver for what the crown and third eye are doing), but there are non-physical levels. Opening the third eye can show you things you're not ready for.
