There are a lot of factors influencing the price of bitcoin, including technical issues/new alts coming out/regulations/stubborn miners/conflicts between developers(or groups)...etc.
What do you think is the most crucial cause? Why did the price drop dramatically these days? Will this be a rebound point?
The answer is "We". We are the one responsible for the different aspects of bitcoin which also includes the changes in bitcoin prices. Many times it happens that we push bitcoin too hard and off limits and then the alternation in the prices happens. For example, consider the cases when bitcoin naturally dropping in its value then people get panic about it and they get so nervous that they cant even hold their breath for a minute and think about the whole situation and immediately start selling everything they have got. This makes the market situation even worst and thus bitcoin loses itself. In same manner prices increases too. I mean when they are done selling everything they have got then they will start thinking that Oh! Its good time to buy the coins and thus in the long they put more money and become responsible for the price rise.