Yes, it is considered disrespectful and offensive to use the term "schizo" or "schizophrenic" to refer to someone with schizophrenia. Using such terms is stigmatizing and can perpetuate negative stereotypes about mental health conditions.
People-first language is an important aspect of promoting empathy and understanding towards individuals with mental health conditions. Instead of labeling someone based on their condition, it is more respectful to use language that emphasizes their personhood first. For instance, it is more appropriate to say "a person with schizophrenia" rather than "a schizophrenic."
Stigma surrounding mental health can be harmful and prevent individuals from seeking help or support. By using respectful and person-centered language, we can contribute to reducing stigma and fostering a more inclusive and compassionate society. It's crucial to treat individuals with mental health conditions with the same respect and dignity as anyone else.