Objective: The establishment of childhood adversities as risk factors for non-affective psychosis has derived a need to consider alternative interpretations of several psychosis-related factors. This paper sought to examine premorbid adjustment trajectories and social outcome factors in relation to childhood adversities. Perceived support has been found to decrease the risk of post-traumatic stress disorder, and we wished to compare perceived support in people with first-episode psychosis to non-clinical control persons and explore its relation to childhood adversities. Method: Every individual presenting with a non-affective first-episode psychosis (F20-29, except F21) in Region Zealand over a 2-year period was approached for participation and the 101 consenting participants were matched to 101 people with no psychiatric disorders. Comprehensive demographic data were collected. Assessment instruments included the Premorbid Assessment Scale, the Global Assessment of Functioning scale and the Childhood Trauma Questionnaire. The latter represented the childhood adversities in addition to parental separation and institutionalization. Results: There were no associations between number of childhood adversities and different social or academic premorbid trajectories. Those with more adversities had lower global functioning the year prior to treatment start and reported lower rates of perceived support during childhood along with less current face-to-face contact with family members. Lack of peer support remained a significant predictor of psychosis when adversities were adjusted for; peer support diminished the risk of psychosis caused by childhood adversities by 10%. Conclusion: Childhood adversities may not predict specific premorbid trajectories, but have an effect on global functioning when the psychosis has begun. Perceived support, especially from peers, may be important in the development of psychosis, and those with more adversities may represent a vulnerable subgroup who need more assistance to increase and maintain supportive networks.