A 70 yr old man presents with 10 prosopagnosia loss of memory, 3rd person hallucination for 1 month. On examination deep Tendon reflexes are increased, mini-mental examination score is 20/30. What is most likely diagnosis:

C i.e. Alzheimer's diseaseDuration of 1 month only, is enough to rule out schizophrenia, in which duration should be at least 6 monthsIn psychiatric disorders like schizophrenia & psychosis, there may never be organic symptoms like increased tendon reflexes.Features of Alzheimer dementia areMemory impairment without impairment of consciousnessAnosognosia (Unaware of his problem) Prosopagnosia (difficulty in identifying known faces)Focal neurological signs (ex asymmetrical hyperreflexia or weakness)Primitive reflexes (ex grasp, snout, suck, Palmo-mental, & tonic foot reflexes)Frontal lobe signsAphasia (language disturbance)Apraxia (impaired ability to carry out motor activities despite intact motor function)Agnosia (failure to recognize or identify objects despite intact sensory function)Disturbance in executive functioning (i.e. planning, organizing, sequencing, abstracting)