Our emotional experiences as well as expressions are heavily influenced by bodily chemicals. For example, hormones secreted by various endocrine glands mixes-up with blood and travel to distant locations within the body. Although this is a relatively slow process to immediately affect the emotional state, it does play crucial role when one has to respond in similar situation in the future. Certain hormones, such as norepinephrine, epinephrine, cortisol, and thyroid hormones, increase during stress, whereas others, such as insulin and testosterone, decreases. We have different types of neurotransmitters that are instrumental in communicating signals across synaptic junctions. They act as chemical messengers. Catecholamines (such as epinephrine, norepinephrine, and dopamine) are involved in extreme emotional reactions. They have been considered potential factors for psychiatric symptoms such as schizophrenia and depression. Similarly, corticosteroids, endogenous opioid peptides and neuromodulators such as prostaglandins are associated with shyness, distress, aggression and fear. The other group of chemicals is the enzymes that are instrumental in m etabolism of endogenous chemicals or exogenous materials, thus indirectly altering mood states.

Emotional experiences also affect changes in the endocrine secretions. Contrarily, such secretions are relatively slow processes and might not directly influence emotional experiences. However, they are likely to predispose an individual to respond in a specific pattern in similar emotion eliciting situations in the future. For instance, elevation of cortisol is associated with anxiety, bereavement and sadness, whereas decrease in cortisol is associated with relaxation and meditation. The table given below highlights the emotional states such as lust, care and distress and the chemical bases of such states.