Presenting Author details:anabarajasvelez@hotmail.com C/Antoni Pujades, 42 (Sant Boi De Llobregat), 08830 Barcelona, Spain, Tel.: +34 6406350x2347; fax: +34 630 53 19. Background: Different studies of first psychotic episodes (FPE) have tried to describe the onset of psychosis. We examine whether FPE with onset during adolescence and childhood (ages 7–17) differ significantly from those with young–adult onset (ages 18–65) in neurological soft signs (NSS) and psychopathology; also, we assess if NSS are associated with negative psychotic symptoms and cognitive functioning in the onset of a FPE. Methods: Cross-sectional study of 28 consecutive cases with a FPE. Inclusion criteria: two or more psychotic symptoms; age range 7 to 65 years; first visit to a centre participating in the study; less than 6 months since first contact with services. Instruments used were a clinical and socio-demographic questionnaire, a battery assessing symptoms, and neurological evaluation scale (NES) and a battery of cognitive tests. Data were analyzed using the non-parametric Mann–Whitney U test and Spearman's correlations by the SPSS. Results: Age of onset distribution was 46.4% adult onset psychosis and 53.6% early onset psychosis having found significant differences between the two groups on measures of NES (p=0.019). NES total score correlates with negative symptoms (r=0.416; p=0.043) and cognitive variables: impulsivity (CPT index, r=0.443, p=0.044), executive functioning (Stroop Color–Word Test, r=−0.522, p=0.018; TMTB, r=−0.636; p=0.003) and working memory (subtests of WAIS/WISC: digit span, r=−0.54, p=0.014; arithmetic, r=−0.599, p=0.007; letter–number sequencing, r=−0.501, p=0.029). Conclusions: A higher level of neurobiological abnormalities in early onset of psychosis could underlie cognitive deficits, especially concerning attention, working memory and executive functioning, and may be related to a prominent negative symptomatology.