Motivation and emotion/Book/2016/Antidepressants and emotion
What are the effects of popular antidepressants on human emotions?
- 1 Overview
- 2 Depression
- 3 Emotion
- 4 Antidepressants
- 4.1 Application
- 4.2 Neural mechanisms of antidepressants
- 4.3 Common types of antidepressants
- 5 Test your knowledge
- 6 How do antidepressants affect emotion?
- 7 Conclusion
- 8 See also
- 9 References
- 10 External links
"it was really alarming at first, since the change was subtle, but I did notice that my surrounding took on a different tone at certain times: the shadows of nightfall seemed more somber, my mornings were less buoyant, walks in the woods became less zestful, and there was a moment during my working hours in the late afternoon when a kind of panic and anxiety overtook me..." - William Styron, Darkness Visible
The emotional hold of depression, the overpowering feelings of anxiety, worthlessness, anger, aggression and guilt have long been studied in attempts to help people regain control over their lives. Antidepressants offer a way out of the constant battle with onesemotions and neurological studies have offered a biological basis for emotional disturbances. Understanding these processes are essential for rehabilitation and the limitations of the usefulness of antidepressants in emotion regulation must also be recognised to prevent relapses or false hope of the treatment.
The following chapter will explore the different types of antidepressants and their neural mechanisms. The effects of these treatments on emotions will also be looked at in relation to their long term and short term benefits. In addition, the limitations of emotional control with the use of antidepressants, such as 'blunted effects,' will also be evaluated.
Depression is a psychological mood disorder and people who suffer from it experience persistent feelings of sadness, hopelessness, worthlessness, guilt and loss of motivation or interest. Depression effects peoples thoughts, feelings, and other behaviours such as eating, drinking and sleeping. There are many interpretations of the underlying mechanisms of depression including the behaviourist theory, psychodynamic theory, cognitive approach theory, and humanist approach theory. According to these, depression can result from interactions within our environment, biological processes and cognitive dispositions.
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What is an emotion?
Emotions are short lived and help us to adapt to opportunities and challenges within our environment. They have synchronized brain activity that influences feelings, bodily responses, purpose, and expression. Emotion also plays a role in motivation as it directs and energizes behavior towards specific goals and is an indicator of how well or how poorly one is adapting to the constantly changing environment. The cause of an emotion stems from many interacting phenomenon such as significant life events, neural activity, cognitive processes, biological processes and feelings, sense of purpose, bodily arousal and social-expression.
Antidepressants are used to treat depressive disorders and are most effective when used in combination with other psychosocial interventions. The main purpose of these drugs is to correct imbalances of neurotransmitters within the brain that are related to changes in emotion, mood and behaviours. The most common neurotransmitters associated with depression are serotonin, norepinephrine and dopamine.
Serotonin is commonly associated with the regulation of sleep, aggression, eating, sexual behaviour, and mood. Tryptophan is a precursor of serotonin and any deficiencies in the production of serotonin through these can lead to depressive symptoms (Neumeister, 2002). Antidepressants aim to reduce the effects of low serotonin levels by preventing the re-uptake of serotonin in the synapse (Neumeister, 2002). Serotonin re-uptake inhibition is one of the most common properties of antidepressants.
The role of norepinephrine is to help our bodies recognise and respond to stressful situations (Moret & Briley, 2011). It is thought that some people may suffer from deficiencies of norepinephrine, resulting in the inability to tolerate stress-induced depressive behaviour (Moret & Briley, 2011). Modifying the norepinephrine system to increase norepinephrine neurotransmissions has shown to be effective in treating emotional and cognitive symptoms of depression, while manipulations to decrease norepinephrine increases chances of depressive relapses (Moret & Briley, 2011).
Dopamine is an important neurotransmitter for the regulation of individualsmotivation to seek out rewards (Rampello et al., 2000). It is also associated with feelings of pleasure and a lack of dopamine can result in depression associated with low motivation and energy for life (Rampello et al., 2000). Serotonin enhances dopamine outflow from neurones and therefore antidepressants such as serotonin re-uptake inhibitors are effective for increasing dopamine release (Rampello et al., 2000).
Neural mechanisms of antidepressants
Neurotransmitters within the brain are used to communicate messages from one neuron to another. Neurotransmitters are housed in vesicles in the presynaptic neuron and are released into the synaptic gap between the presynaptic and postsynaptic neurone (Olijslagers et al., 2006). Receptors of the postsynaptic neuron bind with specific neurotransmitters and are activated. Once the message is received, the postsynaptic receptor releases the neurotransmitter back into the synapse where it can be taken up again by the presynaptic neuron through a process called re-uptake. The neurotransmitters are then repackaged and reused.
People with neurotransmitter deficiencies release less neurotransmitters into the synapse and, due to premature re-uptake, less are attached to their receptor molecules on the postsynaptic neuron. Antidepressant drugs work by blocking the re-uptake channels of neurotransmitters which increases the amount of neurotransmitters in the synapse available for attachment to receptor molecules (Olijslagers et al., 2006). In effect, depressive symptoms associated with low neurotransmitter levels is relieved.