I have low cortisol, and have tried phosphatidyl serine on about 3 occasions at varying times and as part of a complex. Each time it has seriously worsened my insomnia and consequently my overall condition. I suspect because it has pushed my cortisol levels down even further.
I'd say give it a try, but stop straight away if you notice any worsening of your condition. I don't think it should makes things worse before they get better, as some supplements apparently do.