E.T.
Midol contains acetaminophen, caffeine and pyrilamine maleate (an antihistimine). None of those should have any affect on hormones or attitude... except that acetaminophen will decrease pain, so that might make someone a bit happier, and caffeine is a stimulant, so you might get some hyper behavior.
The biggest reason not to do this is that daily use of acetaminophen can damage the stomach, kidneys and liver. Here's a quote from a medical site about side effects: " Prolonged daily use increases the risk of upper gastrointestinal complications such as stomach bleeding and may cause kidney or liver damage."