Final answer:
Genes and biochemical factors, such as neurotransmitters and hormones, play a role in eating disorders and happiness. Imbalance in neurotransmitters and hormones can affect appetite, eating behavior, and mental health. Medications can help balance neurotransmitters and improve symptoms of conditions like depression.
Step-by-step explanation:
Genes are likely to be involved in the development of eating disorders because having a close biological relative with an eating disorder increases one's own risk tenfold or more. At a biochemical level, eating disorders are thought to be caused by the deregulation of neurotransmitters such as serotonin and dopamine. Imbalance in these neurotransmitters is likely to affect appetite and eating behavior. Deregulation of the hormones leptin and ghrelin may also be involved in eating disorders. These two hormones normally help maintain the body's energy balance by increasing or decreasing food intake. This occurs through the regulation of appetite and eating behavior. If these hormones are out of balance, the imbalance will affect appetite and may lead to disordered eating.
Researchers believe that genetic factors influence happiness by means of determining the availability of norepinephrine in the brain and the set point around which happiness tends to settle. These factors can influence the speed of transmission of neural messages and the sensitivity of dopamine receptors. For example, some people have low levels of the neurotransmitter called serotonin in their brain, which is one cause of depression. Medications called antidepressants help bring serotonin levels back to normal and control the symptoms of depression.