I think the bear market is more suitable to buy, then hold it until the bullrun arrives. that's an easy thing to say but in reality it is difficult, full of risk and high patience. 
Maybe you should try to read op questions again. From my understanding, op is asking on "ico investment during bearish market or trends" but you are referring to "investments generally". I don't think it is wise to invest in ico during bearish market as last year is our perfect example.