Final answer:
An imbalance in serotonin can lead to diseases such as depression, anxiety, bipolar disorder, schizophrenia, and ADHD.
Step-by-step explanation:
An imbalance in serotonin can lead to various diseases including depression, anxiety, bipolar disorder, schizophrenia, and Attention Deficient Hyperactivity Disorder (ADHD). In depression, there is a decrease in norepinephrine and serotonin neurotransmission. Medications called antidepressants help bring serotonin levels back to normal to control the symptoms of depression. Similarly, imbalances in serotonin have been implicated in anxiety disorders, bipolar disorder, schizophrenia, and ADHD.