Re: Can gambling be considered a "high risk investment"?
I don't think that it is a good idea to call it even a "high risk investment" because really gambling is an investment with -EV, guaranteed. If you consider that even an investment then I really don't think that you are sane 
However gambling is high risk. Extremely high risk.
That really depends what you call gambling, sportsbetting and poker are some forms of gambling that could be +EV. However gambling is high risk. Extremely high risk.
Another example would be winning a big progressive jackpot and calling it quits after that, not that this would happen often but just to say that gambling isn't always guaranteed to be -EV.