Michael M Prinzing in Psyche:
Theologians sometimes argue that, without the existence of God, life would be meaningless. Some secular people agree. For instance, in his book An Atheist’s Guide to Reality (2011), the philosopher Alex Rosenberg claims that, because the observable physical universe is all that exists, human life is meaningless. Whether you accept this philosophical claim or not, the fact that many people seem to believe that God or other supernatural entities are necessary for life to be meaningful suggests that, psychologically, there is some important connection between religious faith and the sense of meaning in life.
Although psychologists are divided on exactly how to define perceived meaning in life – some suggest it is about making sense of one’s life, others that it’s about seeing value and significance in it – they often assess meaning in life simply by asking how strongly people agree with statements such as: ‘At present, I find my life very meaningful.’ And research has consistently supported the idea that perceived meaning in life is tightly linked with religion.
More here.