 The cavities has the amino phenylbutyric acid in it which is a GABA agonist and it has a a relaxing effect as well as taurine which which is an amino acid and it has a calming effect. The cavities PM does not have taurine but it does have the 5-HTP and the melatonin in it. Well I think before you know which one you should be taking you probably should go for some neurotransmitter testing and this will give you an idea as to which neurotransmitters you are either lacking or in excess of. If you are not having difficulty in falling asleep but staying asleep regular cavities would probably be more appropriate or as if you have difficulty in falling asleep I would surely recommend the one that has the melatonin which is the cavities PM. The cavities is usually dose usually about one capsule three times a day so you can take it during the day as well whereas the cavities ultra PM is recommended to take between one or two at bedtime but no more a maximum of two at bedtime. Yes there are if you are on any SSRIs I surely recommend speaking to your health care professional first before taking them because an increase in serotonin is very likely when these products are taken and that can be dangerous.