Instead of only focusing on mental illness positive psychology also assists in

Positive psychology involves psychological techniques that encourage people to identify and further develop their own positive emotions, experiences, and character traits.
Instead of only focusing on mental illness positive psychology also assists in assessing human strengths.
This type of psychology involves the scientific study of optimal human functioning.

The correct answer is assessing human strengths.

While most branches of psychology focus on mental illness and issues, positive psychology focuses on individual's strengths and abilities. A positive psychologist would encourage his or clients to accept themselves, embrace their uniqueness and focus on celebrating their strengths and accomplishments. Positive psychology looks at what makes life worth living and encourages humans to engage in those things accordingly.