Explain psychological and physical aspect of health, population and environment​

How do healthier citizens save the government money?

How harmful is it to smoke a pack of cigarettes a week?

“an abused child's thoughts occasionally drift to other, less anxiety-arousing topics; this anxiety reduction thus serves to strengthen 'other' thoughts, while weakening the thoughts about abuse.” a psychologist with which theoretical background would be most likely to offer this quotation as an explanation for the development of dissociative disorders?