What might an excess of norepinephrine lead to in terms of mood disorders?

An excess of norepinephrine is often associated with elevated arousal and heightened alertness, which can contribute to symptoms of mania. In mood disorders, mania is characterized by extreme elevations in mood, energy levels, and activity. This state is often accompanied by racing thoughts, decreased need for sleep, impulsivity, and sometimes, irritability. The link between high norepinephrine levels and mania is rooted in the neurotransmitter's role in the brain's activation of the fight-or-flight response, which can enhance mood and energy in excessive amounts.

In contrast, other options represent different aspects of mood disorders. For instance, depression is more commonly linked to deficiencies in neurotransmitters such as serotonin and norepinephrine, while excessive norepinephrine is more indicative of manic or hypomanic states. Anxiety, although it may be influenced by norepinephrine, is more complex and involves a variety of neurotransmitters and psychological factors. Fatigue, on the other hand, typically aligns with low energy states seen in depression rather than the high-energy states associated with an overabundance of norepinephrine.