But you say; "I come from a long line of depressed ancestors, including immediate family members." Many of us did. That's no reason to throw up your hands and wallow in an unhappy mindset, negative feelings, and listless behaviors. Sonja Lyubomirsky, a positive psychologist at the University of California at Riverside, and colleagues have been studying sets of twins. The results have led to the idea of an inborn set point of happiness. Current estimates are that half of one's happiness set point is inherited, 10 percent relates to your environmental circumstances, and 40 percent is under your own power to control. What can you do to up the ante for happiness? Regardless of your inherited predisposition, gratitude can be honed. Robert Emmons of the University of California, Davis, and Mike McCullough of the University of Miami suggest keeping a daily gratitude journal. Just write a few sentences (long-hand electronic) about something for which you are grateful. Research participants who did this for just three months reported higher levels of optimism and fewer visits to physicians. It helped them focus on what they had rather than what they did not have. Remember the old proverb: If you plan to be thankful for what you'll get, be thankful for what you already have.