Genes passed down from family members noticeably reflect the family's nationality, hair color, eye color, height, mannerisms, and talents. But underneath all of these visual displays, the power of genetics affects inner emotions and even outlook on life. A recent study published in the Journal of Affective Disorders studied the power of genetics in influencing the joy of life. Some genes can influence how positively a person views life while other genes affect a person's risk for depression. Researchers compared both genes and found results that those people with genes for life dissatisfaction had a greater risk of developing major depression. Heredity Influencing Life Satisfaction Good things and bad things happen over a person's lifetime and can influence their outlook on life. But from birth, certain genes can already start to work on that person in positive or negative ways. Researchers from the Norwegian Institute of Public Health in collaboration with the University of Oslo conducted a study with fraternal and identical twins to see if depression was linked to the genes that affect overall life satisfaction. Researchers estimated that inherited genes can affect life satisfaction as much as 72 percent. Their results came from the study of the interaction of multiple genes. Specific genes for life satisfaction weren't pinpointed. The study was based on populations rather than individuals. Heredity Influencing Depression Many previous studies have linked depression with heredity. This study's research found that inherited genes can affect depression as much as 34 percent; a percentage similar to those of earlier studies. Both internal and external forces can influence depression. What may begin as sadness for some has the ability to turn into depression for those who have a risk through their genetic makeup. Researchers hope that their findings that link the genes that influence both depression and life satisfaction can help find ways to reduce the risks of depression in individuals. A Combination of Genes While both heredity and environment have powerful effects on a person's life, researchers found that genetics trump environment when relating life satisfaction and depression. Researchers reported that 74 percent of the link between depression and life satisfaction could be interpreted by genes. Twenty-six percent was related to certain environmental factors. Their study found that the men (15.8 percent) and women (11.1 percent) with lifetime major depression also reported overall life dissatisfaction. Looking on the Bright Side of Life Having a positive attitude, as much as is able, truly can help a person carry on when life seems overwhelmingly difficult. Researcher Ragnhild Bang Nes, Ph.D. said that this positive attitude can help reduce risks for depression since genes affect both life satisfaction and depression. With the fact that certain genes relate to positive thoughts and emotions is the hope that these genes can help protect bodies against major depression.