Too much of which neurotransmitter can lead to unwanted jealousy and obsession?

The neurotransmitter that can lead to unwanted jealousy and obsession when present in excess is dopamine. Dopamine plays a significant role in the brain's reward system and is involved in feelings of pleasure, motivation, and reinforcement of rewarding behaviors. When levels of dopamine are elevated, it can create intense feelings of attachment, desire, and the need for reward, potentially leading to obsessive thoughts and behaviors.

In contrast, serotonin is generally associated with mood regulation and a sense of well-being, whereas acetylcholine is primarily involved in muscle activation and cognitive functions like attention and memory. Norepinephrine plays a role in the body’s stress response and attention, but it is not primarily linked to jealousy or obsession in the same way dopamine is. Thus, recognizing the role of dopamine in these emotional states is key to understanding this aspect of behavioral psychology.