Real-world functional deficits are common and persistent in individuals with psychosis. Cognitive deficits have been shown to compromise functioning. We aimed to study the predictive values of premorbid, sociodemographic, and baseline clinical and neurocognitive factors on long-term functional outcome for individuals with first episode non-affective psychosis. We failed to demonstrate a significant relationship between cognitive deficits at baseline and functional disability at 3year follow-up. Diagnosis of schizophrenia (OR=2.457, p=0.011), shorter education (OR=1.177, p=0.005) and poor premorbid social adjustment (OR=1.628, p=0.013) emerged as the strongest predictors for the 114 subjects (56%) that exhibited functional disability at 3-year follow-up. A considerable proportion of the variance in functioning (74% at 1year and 77% at 3year) remained unexplained by baseline variables. The set of variables that predicted functional outcome at medium- (1 year) and long-term (3 years) differed. In conclusion, the length of follow-up influenced the relationship between baseline variables and functional outcome. A substantial proportion of the variance in function was not explained by these variables and therefore the influence of other factors warrants further investigation. The data support the notion that premorbid social adjustment is an important aspect in functional outcome over the course of the illness.