I have use this unit myself, and also for patients. I have not had any patients have adverse effects, and some have reported positive results. Some of that may be due to the Hawthorne effect, but nonetheless, it has been effective in helping people deal with low mood and chronic pain issues. I have found it helpful, when used regularly, in dealing with sleep maintenance, although I do not find it particularly helpful with sleep initiation. I also find energy and mood improved when I use it regularly. Also, and importantly, there are no side effects from this treatment.