That's right! Pursuing positive psychology actually influences your genetic code to turn on (or off) certain expressions, making a difference to your health.
People with high levels of eudaimonic well-being — the kind of happiness that comes from having a
deep sense of purpose and meaning in life — showed very
favorable gene-expression profiles in their immune cells. They had low
levels of inflammatory gene expression and strong expression of
antiviral and antibody genes.
However, people who had relatively high levels of hedonic well-being —
the type of happiness that comes from consummatory self-gratification (as is widely taught in our consumer society) — actually showed just the opposite. They had an adverse
expression profile involving high inflammation and low antiviral and
antibody gene expression.
http://www.sci-news.com/othersciences/psychology/science-positive-psychology-gene-expression-humans-01305.html