Psychologically happiness is an emotional state of joy and satisfaction. It is subjective signs of well-being. Srimadbhagwatgita deals happiness under three categories in chapter 18. The verse 38 deals with Rajsik type of happiness resulted from senses and objects. Generally, such happiness is anticipated by mass. Even, neurobiology of happiness is associated to sensory pleasure. An article published in Journal of Alzheimer’s Disease on 28th September 2021 revealed the links of happiness in early adulthood with dementia. The study was conducted on 15,000 participants between ages 20 to 89. The odds of cognitive impairment were observed 73 percent higher in those having elevated depressive symptoms in early adulthood. Separate studies have highlighted the mechanisms of stress hormones in relation to deleterious effects on brain contributing to cognitive functions.
Second types of happiness mentioned in Srimadbhagwatgita, 18/39 is different. It about the feeling of happiness in sleeping and indolence. It is a kind of Tamasa. An article of Neurology published online on 21st March 2017 evaluates the prolonged sleeping (more than 9 hours) connection with dementia and as marker of neurodegeneration. Even apathy and less physical activities increase the risk of dementia or neurological problems directly or via the cardiovascular pathway.
The happiness felt by soul is regarded as real happiness by philosophers across the globe. Spiritually, Indian texts believe in highest level of happiness through non-attachment based on self-knowledge. Such happiness is Satvik in nature. Neurobiological changes in connection to feelings of non-attachment are not studied so far in details. Only some studies are restricted to mindfulness with control on emotions etc. In one of the study done at Harvard, researchers have observed increased cortical thickness in hippocampus. This also assists in reducing stress, anxiety, fear etc. progressing to improve neurological conditions.
More researches with imaging proofs are required to study in details about the neurological changing occurring in individual types of happiness suggested by Srimadbhagwatgita.