Final answer:
Imipramine can cause sedative effects such as sleepiness, light-headedness, and increased anxiety when given to normal subjects; however, it leads to elevated mood in depressed patients after several weeks of use.
Step-by-step explanation:
Imipramine is a tricyclic antidepressant widely used for the treatment of major depression. When administered to a non-depressed person, it may cause sedative effects such as sleepiness, quietness, a slight drop in blood pressure, lightheadedness, unhappiness, and increased anxiety. Additionally, repeated use might lead to difficulty concentrating and thinking. However, in depressed patients, after continuous usage for about two to three weeks, imipramine can lead to mood elevation, which justifies its use in the treatment of depression. Compared to selective serotonin reuptake inhibitors (SSRIs), such as Prozac, imipramine and other tricyclic antidepressants have more anticholinergic side effects and have a different mechanism of action, namely inhibiting the reuptake of neurotransmitters like epinephrine and serotonin. Due to their side effects and potential for fatal overdose, they are now less commonly used than SSRIs. It's also worth noting that unlike monoamine oxidase inhibitors (MAOIs), tricyclic antidepressants are not usually associated with stimulatory effects in non-depressed subjects.