Human beings need not only food and water for living, but also the interaction with other human beings. This is especially important when living and working in stressful situations. Be it living in a camp as a refugee or IDP, or be it as a social worker supporting people in a community: You need support from other people to keep your head up. This may be your family, or friends, or colleagues.
A psychosocial perspective looks at human functioning in the context of its social environment. So, psychosocial support in very general terms, refers to helping people in dealing with their lives, while taking psychological, social, and circumstantial conditions into account.
The UN defines psychosocial support as follows: Psychosocial support helps individuals and communities to heal the psychological wounds and rebuild social structures after an emergency or a critical event. It can help change people into active survivors rather than passive victims. Disasters, conflicts and health problems have severe psychosocial consequences. The emotional wounds may be less visible than the destruction of homes, but it often takes far longer to recover from emotional impact than to overcome material losses.