serotonin theory of depression

The serotonin theory of depression suggests that a deficiency or imbalance of serotonin—a key neurotransmitter involved in regulating mood, sleep, and other functions—may contribute to depression. The idea is that when serotonin levels are too low or its signaling is disrupted, it can lead to symptoms of depression such as persistent sadness, low energy, and loss of interest. Many antidepressant medications aim to increase brain serotonin levels or enhance its activity to help improve mood and alleviate symptoms. However, while this theory has guided treatment development, depression is complex and involves multiple biological, psychological, and social factors.