This is helpful information but I know of many confident guys with good social skills who became addicted to p 0 r n, and subsequently lost their confidence. As soon as giving up p 0 r n, within a few weeks, their normal charisma returned.
Like you mention, neurochemicals play a large role in depression- and it is worthy to note that addiction to p 0 r n and self-gratification drains the brains neurochemicals par excellence.