The world needs psychology because it allows people to better understand how the mind works. Having this understanding allows mental illnesses to be better diagnosed and managed, helps people manage their relationships with those around them, encourages those with depression or anxiety to take steps to improve their conditions, and promotes an overall healthier mental state.
Psychology is defined by the American Psychological Association as the study of the behavior of individuals and their mental processes. When people understand what is normal in terms of mental development, they are better able to recognize when someone is struggling. This promotes better mental health treatment and encourages early intervention in children struggling with developmental issues.