Real happiness and peace can be found in submiting to the commands Creator and the Sustainer of this world. God has said in the Qur'an
"Truly,in remembering God do hearts find rest."
On the other hand, the one who turns away from Qur'an will have a life of hardsip in this world. God has said
"But whoever turns away from the Qur'an, he will have a hard life, and we will raise him up blind on the day of
Judgment."
This may explain why some people commit suiciede while they enjoy the material comfort money can buy.
For example, look at Cat Stevens (now Yusuf Islam), formely a famous pop singer who use to earn sometimes more than $ 150,000 a night. After he converted to Islam, he found true happiness and peace, which he had not found in material success.
This Yusuf Islam's web site if you like to have a look.
http://catstevens.com/
sara