According to Ayurveda, the root cause of any disease is always the imbalance of tridoshas, or body humors, which further manifests as imbalance in other body components inevitably leading to disease.
Three main causes-
1. Misuse of intellect—prajnaparadha-
•Prajna means "wisdom" or "intelligence", and apradha means "offence". So the literal meaning of prajnaparadha is "an offence against wisdom".
• That is, doing things without discriminating as to whether it is favorable or harmful for the body or mind. These actions may be verbal, mental or physical.
•The actions generated by prajnaparadha aggravate the tridosa and stimulate the rajas and tamas gunas, allowing diseases to become established.
•Excessive/ atiyoga forms of this include talking too much, or excessive thinking, reading, mental work or physical activity.
• A deficiency (hina- yoga) of these actions is not undertaking these activities sufficiently, like not speaking at all or very little, and not working or engaging in any intellectual or physical activity.
•Incorrect (mithya yoga) forms include gossip, lying, inciting violence and irrelevant, illogical or harsh speech. Actions that are motivated by greed, anger, material attachment, envy, ego, fear, grief or delusion also are mithya-yoga.
The physical form of this includes the suppression of natural urges or performing unnatural activity such as smoking cigarettes, driving recklessly or participating in dangerous sports.
2.Misuse of senses—Asatmendriyartha samyoga-
Astmaya means "improper", indriya means "sense organs", artha is "the objects of the senses" and samyoga means "to combine" or "to link".
Asatmendriyartha samyoga refers to improper contact of the senses with their objects, and results in an over stimulation or deficiency of sensory activity.
This harms the body- mind, which requires moderation and harmony internally and externally for healthy functioning .
3.Seasonal variations—parinama or kala-
The external envirorment can trigger disease by unbalancing the body through unnatural or extreme variations in temperature, rainfall or wind.
Excessive or atiyoga of parinama is extraordinary or unexpected climatic conditions, such as excessive heat in summer or cold in winter.
Deficient/ hina- yoga seasonal conditions include very mild temperature variations are not experienced.
Incorrect/ mithya- yoga parinama occurs when conditions are opposite to the normal season, such as being cold in summer or warm in winter.
Parinama or kala also refers more generally to the effects of time, and natural physical transformation that occur over time. For example, seasonal influences on the dosas, and the disorders associated with specific phases of life and aging are all in this category.