MayoClinic.com states that weight gain is a frequent side-effect of almost all antidepressants. Nevertheless, some antidepressants act as appetite stimulants. These include such medicines as monoamine oxidase inhibitors, or MAOIs, and selective serotonin reuptake inhibitors, or SSRIs. Some antidepressants are less likely to cause weight gain and may even help a patient to lose weight if needed. Weight gain while taking antidepressants is not always a drug side effect, however. Sometimes depressed people lose weight, and they may start eating more once they start feeling better.
Monoamine Oxidase Inhibitors
MAOIs reduce depression by elevating the levels of norepinephrine, serotonin and dopamine in the body, says MayoClinic.com. They are the oldest antidepressants and are still commonly used in patients that have not received any help from other antidepressants. MAOIs have numerous side-effects, however. Beside weight gain, patients have also reported that they suffer from insomnia, headaches, hypertension and erectile dysfunctions.
Selective Serotonin Reuptake Inhibitors
According to the HelpGuide.org, SSRIs are among the most widely prescribed antidepressants. They reduce depression by increasing the amount of serotonin in the body. This neurotransmitter or messenger regulates mood and plays a role in such body functions as pain and sleep. When SSRIs were first introduces, doctors believed that they might help the depressed patients lose some weight. It took some time to realize that if these antidepressants were used for more than six months they commonly caused the patients to gain 15 to 20 lbs. over the course of six months, says Depression-Guide.com.
Tricyclic Antidepressants
MayoClinic.com states that tricyclic antidepressants, or TCAs, inhibit the reuptake of such neurotransmitters as serotonin and norepinephrine. TCAs not only reduce depression but also the amount of anxiety that the depressed patients often feel. TCAs increase the risk for heart attack and should be not be used by patients who suffer from enlarged prostate or glaucoma. Beside weight gain, TCAs can cause nausea, sensitivity to sunlight, dizziness, dry mouth, low blood pressure and sexual dysfunctions.
