I thought it was still science fiction but a Google search shows multiple medical studies which combine virtual reality with transcranial stimulation.

Effects of the addition of transcranial direct current stimulation to virtual reality therapy

Combination transcranial direct current stimulation and virtual reality therapy

Facilitation of corticospinal excitability by virtual reality exercise following anodal transcranial direct current stimulation

Effects of anodal transcranial direct current stimulation combined with virtual reality

And it looks like Neuroelectrics is on the verge of commercializing it.

So how soon will Facebook, Microsoft, or Apple combine a virtual reality helmet with transcranial stimulation? Look for small companies like Neuroelectrics to be acquired by the major players in virtual reality.