Youth is more of a mental concept, according to Zhang.

张颐武认为，青春更多的是一个精神层面上的概念。

youdao

The problem with the phrase "I procrastinate" is that it is a mental concept;

“我会拖延”这个短语的问题在于它是一个心理层面的概念。

youdao

Society exists only as a mental concept; in the real world there are only individuals.

社会仅仅以一种精神概念而存在，真实世界中只有个体存在。

youdao

Whether or not optogenetics itself becomes a therapy, Deisseroth hopes he will help psychiatrists move beyond the simplistic concept that mental illness is caused by depressed levels of brain chemicals like serotonin and dopamine.

FORBES: Magazine Article

Under the changes, the partial murder defence of diminished responsibility has been replaced with "a modernised definition", based on the concept of "an abnormality of mental functioning which arose from a recognised medical condition", the ministry said.

BBC: Defence law changes for killing after domestic abuse

The hearing showed agreement in concept on some issues, such as strengthening mental health screening.

CNN: February 1, 2013 -- Updated 0041 GMT (0841 HKT)