Ayurveda states that Kama (lust), Krodha(anger), Lobha (greed), Bhaya (fear) Moha (desires), Irsha (jealousy), Dwesa (hate), Visada (grief), Ego (pride) causes stress, anxiety, & depression and these in next stages lead to physical illnesses. Stressful life and unhealthy lifestyle are the primary reason for all chronic disorders.
Stress usually depends on your adaptability factor. The factors mentioned above reduces your ability to adapt and in turn increases the stress levels. The ability to control negative thoughts, negative actions, control the diversion of mind into other activities, having belief in the existence of a divine power are very few basic ideas for increasing the inner strength & confidence and in turn maintaining a better health.