Patience Problem

My baby is going through a phase where she just screams if she wants anything. I'm really not sure how this came about, but it's annoying. She knows how to use sign language if she wants food or a bottle and we've always been good at paying attention to her signals for play or sleepiness. But now, if she wants anything she screams like a rhesus monkey. It's just "ah, eeh, eeh". And if we don't respond fast enough it becomes a really loud, "eeeeeheeeheeahhhhhh."  Sometimes picking her up to comfort her does no good and she'll just sit with you and scream. It's like she doesn't even know why she's doing it.

Practice makes patience and my husband and I have become quite good at staying calm when our children are having these kinds of meltdowns. We usually manage to keep our cool and try to help calm the irrational child. Sometimes it works, sometimes they end up screaming in their rooms while I eat chocolate and my husband sits in his chair with his eyes closed.

Anyway, the baby was having one of these episodes last night and my husband and I were very patiently holding her, talking to her, trying to figure out what was wrong, and I began to wonder if we were doing the right thing by being so patient? Not that we should be yelling or punishing her in any way. But is there a point where too much patience can hurt a child? Our other two kids went through semi-similar phases, mainly at 2 o'clock in the morning. For them, my husband and I just sucked it up for a few nights and let them cry for 20-30 minutes before they finally decided to go back to sleep. It only took 2-3 nights and it was all over and now they sleep through the night 99.9% of the time. I wonder if we had been more "patient" with their behavior and gotten up and cuddled them and helped them back to sleep, would we still be dealing with sleeplessness 7 years later?

I'm not sure what to do with the baby now. She isn't crying in the middle of the night, she's just crying. There doesn't appear to be any obvious pain or lack of attention. I wonder if we stopped running to her rescue if she would quit screaming so much. The idea of letting her sit and cry is quite horrific to me. Her cute little face all twisted with the pain of knowing no one is coming to make her feel better. But maybe it would be the best thing we could do.