There is no direct link between intelligence and mental illness. However, several studies have found that there may be an association between certain types of mental illness and certain cognitive abilities. For example, some studies have suggested that people with schizophrenia may have lower IQ scores than the general population. Additionally, research has suggested that people with certain mental illnesses, such as bipolar disorder, may have differences in their processing speed, memory, and attention. Overall, the research on this topic is complex and does not provide a clear answer as to whether there is a direct link between intelligence and mental illness. More research is needed to better understand the relationship between mental illness and cognitive abilities.