**Why is suicide haram in Islam? Is it haram in other religions too?
Why do people kill themselves?
What are the facts/reasons behind this act?
What is the thought behind it? An escape from difficulties and hardships of life? 
P.S: I posted here becoz I wanna know the religion point of view and the thought or philosophy behind people committing it…**
Hm. Very good question. I would like to know religious perspective too. Logically I can understand since we believe that life is given by ALLAH swt and we know it belongs to him only. But there may be more to it.
We were sent here for a limit time and that too for a test and only for Allah SWT?s ibadat. There is Ayat which says Allah ki rehmat se bas kaffir hi mayoos hote hain endive our life means we are Mayoos, hume Allah pe yaqeen nahi raha ke He will fix things (Nauz Billah) that?s why Suicide is haram. Rest some knowledgeable person can explain better.
Also it?s said jsine aik insan ko qatal kia usne puri insaniyat ko qatal kia so killing our self if murder too.
If you give someone a gift and they toss it back and tell you, "I don't want it. It's of no use to me"...naturally you will feel hurt and disrespected. But who are we compared to Allah?
Our parents invest so much love and time and energy in raising us and when we take our life away, it's like telling them that all that they have done for us means nothing to us anymore as we don't even value our own life for which they made so many sacrifices for from day 1. I know that the analogy of a parent is a very "human" one. But Rabb is one of Allah's names and a very common one. There is one theory that Rabb is related to the verb, "yurabbi," which means to raise (as in raise a child). Some interpreters think that the word Rabb has a connection to the word Abb which means father. These are just theories. The word Rabb is very expansive in its meaning and includes actions such as cherishing, nourishing, providing, guiding.........which are also the duties of a father or a parent. I know that Allah is above any human comparisons. But if our parents would be so grieved by us taking our lives, then would it not anger Allah even more because he is the One who cherished and sustained us when we were in the wombs of our mothers before we were born...and as per the hadith, He loves us more than a mother loves her child.
We can't compare Allah's loves to human love....but we only have the human perspective to go by. The more fiercely that you love something (such as your child, etc) the more it would hurt/anger/grieve you if that child were to give up on their life because that also means that the child has a disregard for the value of the investment and love you put into their life from day 1.
We can remind ourselves of all of the above as motivation to keep pushing forward in life, but the most difficult thing for many of us is to wholeheartedly resign ourselves to the belief that there is a wisdom of Allah behind all the trials that take place in our lives. It is easier to understand a parent's love. Even when our parents deny us something, we can (at a later point) understand that there was love in their denial as well. But Allah's love and wisdom can sometimes be harder to understand.
Peace @pktun
Yes, suicide is haram in Islam. Is it haram in other religions too, I don’t know. 
“Kill themselves” have vast explanation. For example a person going for ‘Jihad’ knew that he could be get killed, but still he goes for it because he know the ‘purpose’. ‘Motive’, ‘determination’, ‘belief’, madness, ‘mentally disturbance’ and many other provoked thoughts could lead a person to kill him/herself and this is because of ‘some purpose’.
Every beginning have an end of prescribed time and ‘purpose’ is in between both. Being a religious person or follower of a religion, we must get to know what is the ‘purpose’, our life in this world? Once we know that ‘purpose’, I think none or majority will not kill themselves.