Hi, welcome to HCM. Thanks for asking your query at this forum. We understand your concern. I have read your question carefully and understood it. I will try my best to answer it. As you told, your mother is a known patients of Schizophrenia and you have noticed her pre-occupied to self, socially withdrawn, lethargic, sleepy, not communicating much and not able to follow simple instructions like giving you a spoon. This may be either due to prolonged state of schizophrenia or may be symptoms of Post schizophrenic depression. If your mother acknowledges that she is having sadness of mood which persists throughout the day since last many days, then these symptoms along with the above mentioned points towards Post Schizophrenic depression. If she denies sadness then she might be suffering from negative symptoms of schizophrenia. These symptoms are common in chronic patients of Schizophrenia. There occurs cognitive decline also after few months/years causing impaired higher mental function like difficulty in rational thinking, inability to understand a command, impaired judgement etc. She requires further evaluation and personal interview by a psychiatrist to determine the exact illness and then requires optimization of therapy. i hope it answers your query. I wish your mother all the best.