All praise be to Allaah
First of all I recommend you all to watch this video on laughing therapy to know how it is done:
http://www.youtube.com/watch?v
Prophet [sallallaahu 'alaihi wa sallam] said:
"Do not laugh too much, for laughing too much deadens the heart." [Saheeh al-Jaami', 7312]
Based on this hadeeth, there is no doubt that laughing therapy is against Islaam because it contains excessive laugh. The Qur'aan and the Sunnah do not teach us to perform laughing theraphy. But in Islaam, there are many supplications which have been taught by Prophet [sallallaahu 'alaihi wa sallam] in case of distress, sadness, you can refer to:
http://www.turntoislam.com/for