Our world is pretty messed up. With all the violence, pollution and crazy things people do, it would be easy to turn into a grouchy old man without being either elderly or male. There's certainly no shortage of justification for disappointment and cynicism.

But consider this: Negative attitudes are bad for you. And gratitude, it turns out, makes you happier and healthier. If you invest in a way of seeing the world that is mean and frustrated, you're going to get a world that is, well, more mean and frustrating. But if you can find any authentic reason to give thanks, anything that is going right with the world or your life, and put your attention there, then statistics say you're going to be better off.

Does this mean to live in a state of constant denial and put your head in the sand? Of course not. Gratitude works when you're grateful for something real. Feeling euphoric and spending money like you just won the lottery when you didn't is probably going to make you real poor, real quick. But what are you actually grateful for? It's a question that could change your life.

Recent studies have concluded that the expression of gratitude can have profound and positive effects on our health, our moods and even the survival of our marriages.

As Drs. Blaire and Rita Justice reported for the University of Texas Health Science Center, "a growing body of research shows that gratitude is truly amazing in its physical and psychosocial benefits."

In one study on gratitude, conducted by Robert A. Emmons, Ph.D., at the University of California at Davis and his colleague Mike McCullough at the University of Miami, randomly assigned participants were given one of three tasks. Each week, participants kept a short journal. One group briefly described five things they were grateful for that had occurred in the past week, another five recorded daily hassles from the previous week that displeased them, and the neutral group was asked to list five events or circumstances that affected them, but they were not told whether to focus on the positive or on the negative. Ten weeks later, participants in the gratitude group felt better about their lives as a whole and were a full 25 percent happier than the hassled group. They reported fewer health complaints, and exercised an average of 1.5 hours more.

In a later study by Emmons, people were asked to write every day about things for which they were grateful. Not surprisingly, this daily practice led to greater increases in gratitude than did the weekly journaling in the first study. But the results showed another benefit: Participants in the gratitude group also reported offering others more emotional support or help with a personal problem, indicating that the gratitude exercise increased their goodwill towards others, or more tehnically, their "pro-social" motivation.

Another study on gratitude was conducted with adults having congenital and adult-onset neuromuscular disorders (NMDs), with the majority having post-polio syndrome (PPS). Compared to those who were not jotting down their blessings nightly, participants in the gratitude group reported more hours of sleep each night, and feeling more refreshed upon awakening. The gratitude group also reported more satisfaction with their lives as a whole, felt more optimism about the upcoming week, and felt considerably more connected with others than did participants in the control group.

Perhaps most tellingly, the positive changes were markedly noticeable to others. According to the researchers, "Spouses of the participants in the gratitude (group) reported that the participants appeared to have higher subjective well-being than did the spouses of the participants in the control (group)."

There's an old saying that if you've forgotten the language of gratitude, you'll never be on speaking terms with happiness. It turns out this isn't just a fluffy idea. Several studies have shown depression to be inversely correlated to gratitude. It seems that the more grateful a person is, the less depressed they are. Philip Watkins, a clinical psychologist at Eastern Washington University, found that clinically depressed individuals showed significantly lower gratitude (nearly 50 percent less) than non-depressed controls.

Dr. John Gottman at the University of Washington has been researching marriages for two decades. The conclusion of all that research, he states, is that unless a couple is able to maintain a high ratio of positive to negative encounters (5:1 or greater), it is likely the marriage will end.

With 90 percent accuracy, Gottman says he can predict, often after only three minutes of observation, which marriages are likely to flourish and which are likely to flounder. The formula is that for every negative expression (a complaint, frown, put-down, expression of anger) there needs to be about five positive ones (smiles, compliments, laughter, expressions of appreciation and gratitude).

Apparently, positive vibes aren't just for hippies. If you want in on the fun, here are some simple things you can do to build positive momentum toward a more happy and fulfilling life:

1) Keep a daily journal of three things you are thankful for. This works well first thing in the morning, or just before you go to bed.

2) Make it a practice to tell a spouse, partner or friend something you appreciate about them every day.

3) Look in the mirror when you are brushing your teeth, and think about something you have done well recently or something you like about yourself.

Sure this world gives us plenty of reasons to despair. But when we get off the fast track to morbidity, and cultivate instead an attitude of gratitude, things don't just look better -- they actually get better. Thankfulness feels good, it's good for you and it's a blessing for the people around you, too. It's such a win-win-win that I'd say we have cause for gratitude.