AAQ | Unit 1.3.B.2 Serotonin

Introduction
Neurotransmitters play a significant role in mood regulation, anxiety, and overall emotional stability. Recent research has suggested a strong link between serotonin levels and emotional regulation, leading to a deeper understanding of psychological disorders such as depression and anxiety. Researchers believe that if someone has high serotonin levels, then they will have high levels of emotional regulation and stability. This essay will describe a psychological study that aimed to investigate the effect of serotonin manipulation on emotional responses in a controlled experimental setting.

Participants
The study involved 60 participants (30 males and 30 females), aged between 18 and 35 years, recruited from a university population. The participants represented a diverse racial background: 40% Caucasian, 30% African American, 20% Asian, and 10% Hispanic. All participants were screened to ensure they had no history of psychiatric disorders, current use of psychoactive medication, or substance abuse. Additionally, participants were required to be in good general health, with no chronic illnesses that could affect the study’s outcomes. Participants were randomly assigned to one of two groups: the serotonin depletion group or the control group. Participants were assured of their right to withdraw from the study at any time without penalty.
 
Method
The study employed a double-blind, placebo-controlled design. Participants in the serotonin depletion group were administered a tryptophan-free amino acid drink, which temporarily lowered their serotonin levels. The control group received a placebo drink containing a balanced amino acid mixture.

After the administration of the drinks, participants were subjected to a series of emotional tasks designed to elicit responses to positive, neutral, and negative stimuli. These tasks included viewing emotional images, listening to emotionally charged music, and participating in a computerized emotional Stroop task. Emotional responses were measured using self-report scales (such as the Positive and Negative Affect Schedule) and physiological measures (heart rate and skin conductance). Results of the study are displayed below in Source 1, and 2. Assume any differences between groups are statistically significant.


Results and Discussion
In this study, the Amino Acid Mixture group saw an average of 5.6 on the self-report scale, and an average of 6.1 on the physiological measures. In the tryptophan-free amino acid group, the self-report scale was 3.2 on average, and the physiological measures were about 4.3 on average.

These findings support the hypothesis that serotonin plays a critical role in modulating emotional responses. The increase in negative affect and physiological arousal in the serotonin depletion group suggests that lower serotonin levels make individuals more susceptible to negative emotional stimuli and less responsive to positive stimuli. This has significant implications for understanding the biochemical underpinnings of mood disorders and could inform the development of more targeted treatments.

Further research is needed to explore the long-term effects of serotonin manipulation and its impact on different populations, including those with pre-existing mood disorders. Additionally, future studies should investigate the interaction between serotonin levels and other neurotransmitter systems to provide a more comprehensive understanding of emotional regulation.

References
● Harmer, C. J., Cowen, P. J. (2013). "Serotonin and emotional processing: Does it help explain antidepressant drug action?" Neuropharmacology, 67, 89-97.
● Booij, L., Van der Does, A. J. W., & Riedel, W. J. (2003). "Monoamine depletion in psychiatric and healthy populations: Review." Molecular Psychiatry, 8(12), 951-973.


Using the source provided, respond to the following questions:

A. Identify the research method used in the study.
B. State the operational definition of a dependent variable
C. Describe the meaning of the differences in means between the amino acid mixture group, and the tryptophan-free amino acid group.
D. Identify at least one ethical guideline applied by the researchers.
E. Explain the extent to which the research finding may or may not be generalizable using specific and relevant evidence from the study.
F. Explain how at least one of the research findings supports or refutes the researcher’s hypothesis that high levels of serotonin cause high levels of emotional stability and emotional regulation.