Neurocognitive assessments are useful to determine the locus of insult as well as functional capacities of patients on treatment. In psychiatry, neurocognitive assessment is useful in the identification of brain lesions, evaluation of cognitive deterioration over time, and advancement of theories regarding the neuroanatomical localization of symptoms. Neurocognitive models provide a bridging link between brain pathology and phenomenology. They provide a useful framework to understand the pathogenesis of psychiatric disorders, bringing together isolated findings in behavioral, neuroimaging, and other neurobiological studies. This review will discuss neurocognitive model of three disorders – schizophrenia, bipolar disorder, and obsessive compulsive disorder – by incorporating findings from neurocognitive, neuroimaging, and other biological studies.