Antidepressants have side effects, and the common side effects vary from one antidepressant to another. Selective 5-hydroxytryptamine reuptake inhibitors, often referred to clinically as SSRIs, have the most common adverse effects of gastrointestinal reactions, such as nausea, vomiting, and diarrhea, but postprandial dosing, i.e., taking the medication after eating a meal, can alleviate the gastrointestinal reactions to a certain extent. There are also agitation, fidgeting, such as patients with early aggravation of fidgeting symptoms, sleep disorders, this type of side effects lead to accompanying symptoms of anxiety in the early stage of the drug, more anxiety or sleep disruption, often the early stage of the treatment to patients with a combination of benzodiazepines to alleviate the side effects in this regard. Sexual dysfunction, such as difficulty with erection or ejaculation, loss of libido, and frigidity, as well as migraines and tension headaches, may also occur in patients taking the medication.SSRIs also increase the risk of falls, and in some patients, long-term use of SSRIs may result in weight gain. Selective 5-hydroxytryptamine and norepinephrine reuptake inhibitors, also known as SNRs, have common adverse effects similar to those of SSRIs, such as nausea, vomiting, and sexual dysfunction. There are also adverse effects related to norepinephrine activity, such as increased blood pressure, increased heart rate, dry mouth, excessive sweating, and constipation. The most common side effects of tricyclics involve anticholinergic side effects, such as dry mouth, constipation, blurred vision, and difficulty urinating. Cardiovascular system side effects such as upright hypotension, bradyarrhythmia and tachycardia. There are also antihistaminergic side effects, sedation, weight gain and neurological side effects. However, patients do not need to resist medication because of the side effects because, according to clinical experience, the side effects of the newer antidepressants, such as SSRIs and SNRs, are relatively mild in the majority of patients and can be tolerated by those who take them. Generally speaking, the side effects last for about 2 weeks and gradually reduce or even disappear.