These spectrum disorders tend to be chronic illnesses that cause severe communal and personal side effects. SSDs (schizophrenia spectrum disorders) display symptoms similar to psychotic symptomatology, such as hallucinations, speech changes, and delusions. Out of all these disorders, schizoaffective disorder and schizophrenia tend to occur the most often (whether it is in adolescence or early adulthood). Both of these disorders display a significant overlap in clinical symptoms, leading some research to question whether they are distinct or not.