The final cause and also the most obvious cause but Bitcoin price dropped the most, this is the psychological sell off from investors. Young trader and inexperienced trader easily fall into panic when the market shows signs of decline, followed by a wave of selling off and the situation becomes worse.
Indeed that is also what I am seeing and currently observing that upon reading in the entire forum, I see newbies are getting into panic of the assets they are currently holding together with those who have jnvested when the price of Bitcoin spikes really high last December 2017. If this will not stop and just continuously happening over and over again, we might be expecting more downfall but it will not totally clarify that the era of Bitcoin will soon to end. It is just that panic among people makes them paranoid of selling at a much lower price to attract buyers to buy their assets on sale.