Real happiness and peace can be found in submitting to the commands of the Creator and the Sustainer of this world. God has said in the Quran:
“Truly, in remembering God do hearts find rest.” (Quran 13:28)
https://www.youtube.com/watch?v=f0yvMkYYVIw&list=PLPAC5UrOJpg5yHWimNbrAsRWOBWvxb5iY
On the other hand, the one who turns away from the Quran will have a life of hardship in this world. God has said:
“But whoever turns away from the Quran, he will have a hard life, and We will raise him up blind on the Day of Judgment.” (Quran 20:124)
This may explain why some people commit suicide while they enjoy the material comfort money can buy. For example, look at Cat Stevens (now Yusuf Islam), formerly a famous pop singer who used 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.