Over the years, there have been many theories about emotions, with different hypothesis provided by various psychologists. Researchers have tried to establish a somatic, empirical, evolutionary, and cognitive connection between emotions and resultant behaviors.
Emotion is an unconscious process. Modern psychologists suggest that emotions are a state where the brain attributes a positive or negative value to external and internal stimuli. The emotions, in most cases, furnish a plan of action. Simply stated, there is a quick and automatic assessment by the nervous system that brings in appropriate actions based on subjective experiences. For example, if you are being threatened, the rising fear directs the brain to drop whatever you are doing and find routes of escape.
Emotions are a subject matter of emotional neuroscience. This science tries to understand various disorders connected to emotions. It is now believed that chemical imbalances and the lesser availability of neurotransmitters are responsible for emotional disorders like anxiety and depression. Neurotransmitters are organic substances that occur in neural activity and transmit nerve impulses across a synapse.
Neurotransmitters like dopamine, noradrenaline and serotonin increase or decrease the brain's activity level. Specifically, serotonin is involved in sleep, depression and memory. It is for this reason that the first prescription for depression is most likely a SSRI, also known as a selective serotonin uptake inhibitor.
However, low serotonin is not the finite cause of depression. What actually causes serotonin levels to drop is not known to medical science, despite extensive research on the subject.
Research provides us with possible reasons like genetics and improper brain development behind a drop in serotonin levels and chemical imbalances. Another theory that has gained plausibility is that our own thoughts and behaviors affect serotonin levels. If you are negative in your approach and do not participate in activities that give pleasure, your serotonin levels are likely to drop.
It is hard to believe, but the hypothesis is based on the fact that whatever we do and think happens due to production, release, and absorption of chemicals like hormones, neurotransmitters, and amino acids. When we have to deal with stress over a prolonged period, it forces the brain to cycle through serotonin more rapidly. This is mainly done to control stress and overall mood, thus reducing the availability of serotonin. Similarly, when we feel positive, there is a better availability of serotonin.
Emotions are considered to be related to brain areas that direct our attention, motivate our behavior, and determine the significance of what is going around us.References: