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) 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,1 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.