Factors that contribute to suicide:

1) Recognition that people with a properly functioning brain almost NEVER commit suicide.  It needs a malfunction of the brain.

2) Areas with HIGHER altitude have a higher suicide rate.  Notice that it runs right through the Rocky Mountains. There are many possible explanation but perhaps the easiest to understand is that there is less oxygen at higher altitudes.  The brain needs oxygen to function appropriately.  Any slight malfunction is magnified by the lack of oxygen in the body.

3) Seasonal Affective Disorder is real.  This has 2 major contributing factors.  When blue light hits that back portion of your eye, it triggers the production of serotonin.  When people don't get enough sunlight on their eyes, the serotonin production in the brain is thrown out of balance.  This occurs in areas further north (where there is less sunlight in a day).  And areas with HIGH cloud coverage like Washington and Oregon.  From September to February/March people are moving into higher and higher deficits of serotonin production and the brain slowly slides out of balance.  This is then corrected in the spring time.

4) Also contributing to SAD is the lack of Vitamin D absorbtion.  Crucial to proper body function.  The primary source of this is D through the skin from the sun.

— So Conclusions?

1) Where people live happy principled lives in general, and are free from vices they will have a "Happier" State. 

2) Where Mental illness manifests itself, suicide rates will be higher in states with less oxygen/sunlight.

NOTE: This is an overly simplistic explanation, but does come to bear on at least some of the factors.  There are also many other factors that contribute to this, such as a healthy diet, medical care, cultural, 13-26 year olds as percent of population (age in which mental illnesses normally manifest and people are most susceptible to suicide), etc.