This systematic review provides a comprehensive neuropsychological analysis of psychotic spectrum disorders, including schizophrenia, bipolar disorder, and depression. It explores cognitive impairments in memory, attention, and executive function, and the relation between brain abnormalities and these deficits. The paper emphasizes the use of neuropsychological tests in diagnosis and early psychosis management, while also discussing interventions, the impact of dementia on psychosis, and the neurobiological patterns associated with these conditions. Additionally, it underlines the importance of childhood trauma in the development of psychosis and examines the effects of substance abuse and brain injury. Neuropsychological evaluations and targeted therapies are highlighted as crucial for the understanding, diagnosis, and treatment of psychotic disorders. The research further includes evidence of neurocognitive dysfunction in individuals with a high risk of psychosis and emphasizes the advanced brain aging in schizophrenia and bipolar disorder. The necessity of comprehensive clinical evaluations and targeted therapies for cognitive impairments is underscored throughout the research. The potential effects of dementia on individuals with psychosis, neurobiological patterns, the role of childhood trauma, the impact of psychosis in dementia patients, and proposed treatments are also explored in depth. Overall, the paper underscores the integral role neuropsychological knowledge plays in understanding, diagnosing, managing, and treating psychotic spectrum disorders.