Overall, it appears from these results that cryptocurrencies may experience short term intervals of co-movement, caused by sector wide news or cross market contagion, though correlation is likely to change dependent on the nature of the causal event and market environment. In the medium and longer term Bitcoin and Litecoin are strongly related; it is believed this is due to their similarity.
Cochrane, J. H. (2005), “Financial markets and the real economy”, Foundations and Trends in Finance 1 (1), 1–101.

But even this kind of pullback could not kill the inherent uptrend and in one of our previous reports, we mentioned that a breakout above $62,500 was required for BTC to resume strength.
All the signs, however, were there. Like previous bubbles, people were basing their belief in the cryptocurrency on their emotions, not any intrinsic value. Then there was the FOMO element, which only compounded things. Essentially, bitcoin became an international fever. Random companies were “pivoting to blockchain” for no apparent reason other than that it seemed like a way to create buzz. But when the bubble bursts, FOMO turns into fear of losing, which makes for an especially rapid plunge.