Draft an Insurance Medical Necessity Appeal Letter

Draft a medical necessity letter for an insurance appeal for continued outpatient mental health treatment. Diagnosis: [diagnosis category]. Current treatment: [modality, frequency, number of sessions completed]. Reason for denial: [denial reason if known]. Patient functional impairment: [describe impact on work, relationships, or daily functioning — general, not specific to a named client]. Write 3 paragraphs: clinical presentation, treatment rationale and progress, and medical necessity argument. Use DSM-5 language. Professional tone.