Does schizophrenia affect (reduce) intelligence? theres research that says 30 of the patients have an iq decline of less than 10 points, is decline resulted from attention, memory function getting affected, or intelligence getting affected directly?

It is my professional opinion as shared by CCHR.org & the late Dr Szasz that there are no biological markers for this subjective diagnosis & label by psychiatrists & so the diagnosis must always be questioned. However, nutritional deficiencies, food allergies, toxins, poor physical conditioning, poverty, & lack of positive stimulation for your brain can cause problems which should be addressed.