Some hypnotherapists offer healings over the internet, whereas some other don't. I'd like to know how successful is hypnosis or hypnotherapy over a distance, for example, over Skype?
A literature review was conducted Barak et al. (2008) that compared the effectiveness of internet-based psychotherapy in general (not specifically hypnosis). From their abstract, the results indicate that:
The overall mean weighted effect size was found to be 0.53 (medium effect), which is quite similar to the average effect size of traditional, face-to-face therapy.
[...] examined interacting effects of various possible relevant moderators of the effects of online therapy, including type of therapy [...], type of outcome measure, time of measurement of outcome (post-therapy or follow-up), type of problem treated, therapeutic approach, and communication modality, among others. A comparison between face-to-face and Internet intervention as reported on in 14 of the studies revealed no differences in effectiveness.
In short, the studies reviewed,
provide strong support for the adoption of online psychological interventions as a legitimate therapeutic activity [...].
I think you would have to define 'successful' before you could get a meaningful answer to this question. Is success a happy client? Maybe a deep trance state? Or a trance state at all? My professional experience with skype and hypnosis is that it is much harder to determine the client's state from a monitor than in person. Feedback is limited in that you cannot hear breathing changes, see small movements easily or easily hear quietly spoken words. On top of this, you have the possibility of disconnection at any moment that makes the practice more challenging since the client will not know that you are disconnected versus just being quiet, and is likely to either fall asleep or become alarmed/alerted after some time has passed. Neither of those would be considered successful in my mind.