There are three major factors that are related to the development of mental illness . describe two biological causes that may influence the development of mental illness in an individual.

The answer is genetic and health habits.

Genetics act as a predisposing factor. Studies have shown that having some genes makes one susceptible to mental illness especially at older ages. An example is the DISC1 gene, which has been associated with schizophrenia.

Health habits that expose one to mental illness include poor nutrition, exposure to toxins such as lead and substance abuse.

risky behaviors. many behaviors are risky for your health and happiness. the main hazards include using tobacco, alcohol, and sexual activity.