???????? Do you believe that homosexuality is abnormal? Why or why not? The question of where to draw the line between normal and abnormal behavior continues to be a subject of debate within the mental health field and the broader society. Unlike medical illness, a psychological or mental disorder cannot be identified by a spot on an X-ray or from a blood sample. Classifying these disorders involves clinical judgments, not findings of fact; and as we have noted, these judgments can change over time and can vary from culture to culture. For example, medical professionals once considered masturbation a form of mental illness. Although some people today may object to masturbation on moral grounds, professionals no longer regard it as a mental disturbance.

Consider other behaviors that may blur the boundaries between normal and abnormal: Is body-piercing abnormal, or is it simply a fashion statement? (How much piercing do you consider

“normal”?) Might excessive shopping behavior or overuse of the Internet be forms of mental illness? Is bullying a symptom of an underlying disorder, or is it just bad behavior? Mental health professionals base their judgments on the kinds of criteria we outline in this text. But even in professional circles, debate continues about whether some behaviors should be classified as forms of abnormal behavior or mental disorders.