Fluphenazine dihydrochloride is primarily used in the treatment of psychotic disorders, such as schizophrenia. It helps manage symptoms like hallucinations, delusions, and disorganized thinking by altering the effects of certain chemicals in the brain. It is also prescribed for severe anxiety or agitation in other mental health conditions. The medication is often administered in long-acting injectable forms, providing sustained symptom control for patients who may struggle with daily oral medication adherence. Additionally, it is sometimes used in combination with other therapies to enhance overall treatment effectiveness.