When depression, anxiety, or PTSD resist standard treatments, new drugs and protocols are available. They work in differnt ways, offering new hope for a higher quality of life. Low-dose naltrexone LDN produces an unusual rebound effect improving the way the body handles its own endorphins in three ways. Endorphins are natural hormones that inhibit pain signals and upregulate mood. Cells have specific receptors to receive endorphins called OGFrs.