The major catalyst for the development of positive youth development came as a response to the negative and punitive methods of the "traditional youth development" approach. The traditional approach makes a connection between the changes occurring during adolescent years and either the beginning or peaking of several important public health and social problems, including homicide, suicide, substance use and abuse, sexually transmitted infections and teen and unplanned pregnancies.[5] Another aspect of the traditional approach lies in that many professionals and mass media contribute to it through the portrayal of adolescents as "inevitable problems" that simply need to be fixed. Specific evidence of this "problem-centered" model is present across professional fields that deal with young people.