MAOIs hold the potential to induce life-threatening problems. The Side Effects associated with its use are hypertensive crisis, rapid heartbeat, blood cell problems, insomnia, dizziness, headache, fluid retention, and loss of appetite. It therefore cannot be used in patients of congestive cardiac failure or in those with a history of liver disease. It is unsafe for those who are hypersensitive to its ingredients.

Though the type of Side Effects experienced by the patient due to TCAs or MAOIs are many times similar, the frequency of these Side Effects is much less in the case of TCAs. Thus, TCAs enjoy a better rate of acceptance by the patients. The potential Side Effects of TCAs are allergic reactions, blood cell problems, blurred vision, dry mouth, weakness, fatigue, weight gain, constipation, difficulty with urination, sexual dysfunction, sweating, muscle twitches, rash, dizziness, tremors, ECG abnormalities, seizures, stroke, and Neuroleptic Malignant Syndrome (with amoxapine). The secondary amine TCAs (desipramine and nortriptyline) are generally better tolerated than tertiary amine TCAs.

The SSRIs are associated with nausea, anorexia, anxiety, agitation, insomnia, headache, dizziness, tremor somnolence, sweating, dry mouth, diarrhea, constipation, and sexual dysfunction as the general Side Effects. The sexual Side Effects of SSRIs often become the reason for its desired discontinuation.

The currently available SNRIs (desipramine, duloxetine, nefazodone, and venlafaxine) keep both serotonin and norepinephrine at the right level to alleviate depressive symptoms. The Side Effects associated with the use of nefazodone include dry mouth, constipation, and somnolence. Venlafaxine has significant anticholinergic effects (dry mouth, blurred vision, urinary hesitancy, and constipation) and induces sedation. Other Side Effects observed with its use are hypertension, agitation, tremor, sweating, headache, nausea and sleep disturbances. It has potential withdrawal effects.

The drug bupropion (Wellbutrin, Wellbutrin SR) is contraindicated in patients with seizure disorder or a history of anorexia nervosa or bulimia. Agitation, tremor, insomnia, decreased appetite, GI upset and psychoses are the bupropion-induced common Side Effects. The most common adverse effects of mirtazapine (a tetracyclic Antidepressant) include increased appetite, weight gain, lethargy and dizziness.

The most commonly associated Side Effects with the use of St. Johns wort (a natural Antidepressant) include fatigue, sedation, restlessness, anxiety, headache, dizziness, dry mouth, gastrointestinal symptoms, and skin reactions. Studies have reported that the rates of adverse events with St. Johns wort are comparable to those with a placebo.