By Alden Bentley (Reuters) – War. Inflation. Polarization. Appalling headlines ricochet around the internet, stocks are skidding, wealth is eroding and the mood on Wall Street has rarely been gloomier. While some opportunists thrive in adversity, experts say that for many investors it takes a toll on mental health. Relatively new fields in psychology and economics examine investor behavior, herd mentality, panic, mania and hidden biases that affect decision making – often in ways that negatively affect portfolio performance. Nobel prizes have been awarded to several behavioral finance pioneers…