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 major reason of its highs ang lows is the population of investors who are gaining ang losing their interest in investing. If the bitcoin is in demand, it goes high if it is not then it drops very low. That's what happens and I think it's the most disturbing problem of bitcoin.