New research suggests that self-worth is at the heart of many mental disorders.

Researchers from the University of California-Berkeley found that inflated or deflated feelings of self-worth have been linked to such afflictions as bipolar disorder, narcissistic personality disorder, anxiety and depression, providing yet more evidence that the widening gulf between rich and poor can be bad for their health.

"We found that it is important to consider the motivation to pursue power, beliefs about how much power one has attained, pro-social and aggressive strategies for attaining power, and emotions related to attaining power," Sheri Johnson, senior author of the study, said in a statement.

For the study, researchers collected data from more than 600 young men and women. They looked at how study participants fit into the "dominance behavioral system," a construct in which humans and other mammals assess their place in the social hierarchy and respond accordingly to promote cooperation and avoid conflict and aggression. The concept is rooted in the evolutionary principle that dominant mammals gain easier access to resources for the sake of reproductive success and the survival of the species.

They concluded that one's perceived social status -- or lack thereof -- is at the heart of a wide range of mental illnesses. The findings make a strong case for assessing such traits as "ruthless ambition," "discomfort with leadership" and "hubristic pride" to understand psychopathologies.

"People prone to depression or anxiety reported feeling little sense of pride in their accomplishments and little sense of power," Johnson said. "In contrast, people at risk for mania tended to report high levels of pride and an emphasis on the pursuit of power despite interpersonal costs."

Overall, the results showed a strong correlation between the highs and lows of perceived power and mood disorders.

"This is the first study to assess the dominance behavioral system across psychopathologies," Johnson said. "The findings present more evidence that it is important to consider dominance in understanding vulnerability to psychological symptoms."

The findings are detailed in the journal Psychology and Psychotherapy: Theory, Research and Practice.