To find the most effective
pharmaceutical drug treatment, the dosages of medications must often be adjusted, different combinations of antidepressants tried, or antidepressants changed. Some of the medications have side effects that affect certain people in different ways. The combinations of medication can change these side effects, so it is essential to monitor the changes that occur once we begin medication.
Serotonin modulator and stimulator Vortioxetine is a multimodal antidepressant that can be more effective than some other antidepressants.
Selective serotonin reuptake inhibitors Selective serotonin reuptake inhibitors (SSRIs), such as
sertraline (Zoloft, Lustral),
escitalopram (Lexapro, Cipralex),
fluoxetine (Prozac),
paroxetine (Seroxat), and
citalopram, are the primary medications considered, due to their relatively mild side effects and broad effect on the symptoms of depression and anxiety, as well as reduced risk in overdose, compared to their older tricyclic alternatives. Those who do not respond to the first SSRI tried can be switched to another. If sexual dysfunction is present prior to the onset of depression, SSRIs should be avoided. Another popular option is to switch to the atypical antidepressant
bupropion (Wellbutrin) or to add bupropion to the existing therapy; this strategy is possibly more effective. It is not uncommon for SSRIs to cause or worsen insomnia; the sedating
noradrenergic and specific serotonergic antidepressant (NaSSA) antidepressant
mirtazapine (Zispin, Remeron) can be used in such cases. For children and adolescents with moderate-to-severe depressive disorder, fluoxetine seems to be the best treatment (either with or without
cognitive behavioural therapy) but more research is needed to be certain. Sertraline, escitalopram,
duloxetine might also help in reducing symptoms. Evidence of effectiveness of SSRIs in those with depression complicated by
dementia is lacking.
Norepinephrine dopamine reuptake inhibitor Some
norepinephrine–dopamine reuptake inhibitors can be used as antidepressants.
Norepinephrine reuptake inhibitor Norepinephrine reuptake inhibitors (NRIs) can be used as antidepressants.
Serotonin norepinephrine reuptake inhibitor Venlafaxine (Effexor) from the SNRI class may be moderately more effective than SSRIs; however, it is not recommended as a first-line treatment because of the higher rate of side effects, and its use is specifically discouraged in children and adolescents.
Tricyclic antidepressant Tricyclic antidepressants (TCAs) have a different side effect profile than SSRIs. In a study of inpatients the tricyclic antidepressant
amitriptyline, in particular, appears to be more effective.
Monoamine oxidase inhibitor Monoamine oxidase inhibitors, have historically been plagued by questionable efficacy (although early studies used dosages now considered too low) and life-threatening adverse effects. They are still used only rarely, although newer agents of this class (
RIMA), with a better side effect profile, have been developed. In older patients TCAs and SSRIs are of the same efficacy. However, there are differences between TCA related antidepressants and classical TCAs in terms of side effect profiles and withdrawal when compared to SSRIs. A nasal spray formulation of
esketamine, sold under the brand name Spravato, gained FDA approval in 2019 for the treatment of treatment-resistant depression when combined with an oral antidepressant.
Dextromethorphan Dextromethorphan/bupropion, sold under the brand name Auvelity, is a combination medication approved by the US FDA in 2022 for the treatment of major depressive disorder (MDD) in adults. The formulation pairs
dextromethorphan, an N-methyl-D-aspartate (NMDA) receptor antagonist and
sigma-1 receptor agonist, with bupropion, a norepinephrine-dopamine reuptake inhibitor that also functions as a
CYP2D6 enzyme inhibitor. Bupropion is included in the combination to slow the metabolism of dextromethorphan by inhibiting CYP2D6, thereby increasing its bioavailability and allowing dextromethorphan's potential antidepressant effects to be achieved. While the precise mechanism of action in treating depression is not fully understood, it is hypothesized that the medication works by modulating glutamate signaling and influencing other neurotransmitter systems.
Zinc A 2012 cross-sectional study found an association between zinc deficiency and depressive symptoms among women, but not men, and a 2013 meta-analysis of 17 observational studies found that blood zinc concentrations were lower in depressed subjects than in control subjects. A 2012 meta-analysis found that zinc supplementation as an adjunct to antidepressant drug treatment significantly lowered depressive symptom scores of depressed patients. The potential mechanisms underlying the association between low serum zinc and depression remain unclear, but may involve the regulation of neurotransmitter, endocrine and neurogenesis pathways. Zinc supplementation has been reported to improve symptoms of
ADHD and depression. A 2013 review found that zinc supplementation may be an effective treatment in major depression.
Acetyl-l-carnitine Acetylcarnitine levels were lower in depressed patients than controls and in rats it causes rapid antidepressant effects through epigenetic mechanisms. A systematic review and meta-analysis of 12 randomized controlled trials found "supplementation significantly decreases depressive symptoms compared with placebo/no intervention, while offering a comparable effect with that of established antidepressant agents with fewer adverse effects."
Augmentation Physicians often add a medication with a different mode of action to bolster the effect of an antidepressant in cases of treatment resistance; a 2002 large community study of 244,859 depressed Veterans Administration patients found that 22% had received a second agent, most commonly a second antidepressant. Stephen M. Stahl, renowned academician in psychopharmacology, has stated resorting to a dynamic
psychostimulant, in particular,
d-amphetamine is the "
classical augmentation strategy for treatment-refractory depression". However, the use of stimulants in cases of treatment-resistant depression is relatively controversial. It is also possible to use a benzodiazepine as to improve sleep without impairing the antidepressant response specially in patients presenting symptoms of insomnia and disturbed sleep. A randomized controlled trial found that the use of eszopiclone with fluoxetine resulted in a better remission rate. Addition of
atypical antipsychotics when the patient has not responded to an antidepressant is also known to increase the effectiveness of antidepressant drugs, albeit at the cost of more frequent and potentially serious side effects.
Lithium Lithium has been used to augment antidepressant therapy in those who have failed to respond to antidepressants alone. As an augmentation agent for major depression, lithium is much more effective than placebo. Lithium augmentation has proven efficacy in treating major depressive disorder in multiple
randomized controlled trials. For treatment-resistant depression, lithium augmentation reduces the odds of remaining ill by 56-95%. In the STAR-D study, for patients who had not achieved remission with two previous treatment trials, an additional 15.9% achieved remission. In addition to its effects on suicide, lithium also decreases mortality from all causes in people with mood disorders.
Thyroid hormones There is some evidence for the addition of a thyroid hormone,
triiodothyronine, in patients with normal thyroid function. For TRD patients, T3 has been studied in the STAR-D study with having a remission rate of 24.7%. T4 is also being studied for this purpose and found remission rates of 21.5%–64.7% for TRD patients.
Regulatory status, efficacy and tolerability of adjunctive treatments in depression Efficacy of medication and psychotherapy Antidepressants are
statistically superior to
placebo but their overall effect is low-to-moderate. In that respect they often did not exceed the
National Institute for Health and Clinical Excellence criteria for a "clinically significant" effect. In particular, the effect size was very small for moderate depression but increased with severity, reaching "
clinical significance" for very severe depression. These results were consistent with the earlier clinical studies in which only patients with severe depression benefited from either psychotherapy or treatment with an antidepressant,
imipramine, more than from the placebo treatment. Despite obtaining similar results, the authors argued about their interpretation. One author concluded that there "seems little evidence to support the prescription of antidepressant medication to any but the most severely depressed patients, unless alternative treatments have failed to provide benefit." Antidepressants in general are as effective as psychotherapy for major depression, and this conclusion holds true for both severe and mild forms of MDD. In contrast, medication gives better results for
dysthymia. Similarly, TORDIA showed a 55% improvement with CBT and drugs versus a 41% with drug therapy alone.
Treatment resistance The risk factors for treatment resistant depression are: the duration of the episode of depression, severity of the episode, if bipolar, lack of improvement in symptoms within the first couple of treatment weeks, anxious or avoidant and borderline comorbidity and old age. Treatment resistant depression is best handled with a combination of conventional antidepressant together with atypical antipsychotics. Another approach is to try different antidepressants. It's inconclusive which approach is superior. Treatment resistant depression can be misdiagnosed if subtherapeutic doses of antidepressants is the case, patient nonadherence, intolerable adverse effects or their thyroid disease or other conditions is misdiagnosed as depression.
Experimental treatments Ayahuasca Research into ayahuasca has been recommended, given there is limited early evidence of potential
antidepressant and
anxiolytic effects.
Bretisilocin In March 2026,
bretisilocin entered
European Medicines Agency's priority medicines (PRIME) scheme for major depressive disorder, while a phase 2 clinical trial was still ongoing.
Chromium Clinical and experimental studies have reported antidepressant activity of
chromium particularly in
atypical depression, characterized by increased appetite and carbohydrate craving. Studies on mice have found that the antidepressant effects of creatine can be blocked by
dopamine receptor antagonists such as
haloperidol, suggesting that the drug acts on dopamine pathways.
Inositol Inositol, a sugar alcohol in fruits, beans, grains and nuts, was found to be significantly better than placebo in treating depression in a double-blind, controlled trial. It was also reported to be reduced in human CSF in depression and found to lead to "major improvement" in 9 of 11 depressed patients in an open label trial.
Magnesium A meta-analysis has found an association between
magnesium intake and depression. Magnesium was lower in serum of depressed patients than controls. A 2018 review found that Mg2+ supplementation (range 225–4000 mg) and number of weeks of treatment (range 1–12) were not related to changes in mood disorder. A 2016 review found that if trials with formulations containing mostly
eicosapentaenoic acid (EPA) are separated from trials using formulations containing
docosahexaenoic acid (DHA), it appeared that EPA may have an effect while DHA may not, but there was insufficient evidence to be sure. A 2020 meta-analysis showed that a high dose of omega-3 polyunsaturated fatty acid (>2 g/day) used as an adjuvent improved depressive symptoms.
Dopamine receptor agonist Some research suggests
dopamine receptor agonists, most commonly
pramipexole, may be effective in treating depression. Studies are few and results are preliminary, however.
N-Acetylcysteine A systematic review and meta-analysis of 5 studies found that
N-acetylcysteine reduces depressive symptoms more than placebo and has good tolerability. N-acetylecysteine may exert its benefits by replenishing the chief cellular antioxidant,
glutathione, thus modulating glutamatergic, neurotropic and inflammatory pathways.
Psilocybin Psilocybin has been shown in several studies to improve symptoms in people with treatment-resistant depression. In 2018 and 2019, the FDA designated psilocybin as a "
breakthrough therapy" for drug-resistant depression and major depressive disorder.
St John's wort A 2008
Cochrane Collaboration meta-analysis concluded that "The available evidence suggests that the
hypericum extracts tested in the included trials a) are superior to placebo in patients with major depression; b) are similarly effective as standard antidepressants; c) and have fewer
side effects than standard antidepressants. The association of country of origin and precision with effects sizes complicates the interpretation." The United States
National Center for Complementary and Integrative Health advice is that "St. John's wort may help some types of depression, similar to treatment with standard prescription antidepressants, but the evidence is not definitive." and warns that "Combining St. John's wort with certain antidepressants can lead to a potentially life-threatening increase of
serotonin, a brain chemical targeted by antidepressants. St. John's wort can also limit the effectiveness of many
prescription medicines."
Rhodiola rosea A 2011 review reported
Rhodiola rosea "is an adaptogen plant that can be especially helpful in treating asthenic or lethargic depression, and may be combined with conventional antidepressants to alleviate some of their common side effects."
Saffron A 2013 meta-analysis found that
saffron supplementation significantly reduced depression symptoms compared to placebo, and both saffron supplementation and the antidepressant groups were similarly effective in reducing depression symptoms. A 2015 meta-analysis supported the "efficacy of saffron as compared to placebo in improving the following conditions: depressive symptoms (compared to anti-depressants and placebo), premenstrual symptoms, and sexual dysfunction. In addition, saffron use was also effective in reducing excessive snacking behavior." Therapeutic doses of saffron exhibits no significant toxicity in both clinical and experimental investigations.
SAMe S-Adenosyl methionine (SAMe) is available as a prescription antidepressant in
Europe and an over-the-counter
dietary supplement in the US. Evidence from 16 clinical trials with a small number of subjects, reviewed in 1994 and 1996 suggested it to be more effective than placebo and as effective as standard antidepressant medication for the treatment of major depression.
Tryptophan and 5-HTP The
amino acid tryptophan is converted into
5-hydroxytryptophan (5-HTP) which is subsequently converted into the
neurotransmitter serotonin. Since serotonin deficiency has been recognized as a possible cause of depression, it has been suggested that consumption of tryptophan or 5-HTP may therefore improve depression symptoms by increasing the level of serotonin in the brain. 5-HTP and tryptophan are sold
over the counter in North America, but requires a prescription in Europe. The use of 5-HTP instead of tryptophan bypasses the conversion of tryptophan into 5-HTP by the enzyme
tryptophan hydroxylase, which is the rate-limiting step in the synthesis of serotonin, and 5-HTP easily crosses the blood–brain barrier unlike tryptophan, which requires a transporter. The safety of these medications has not been well studied. Due to the lack of high quality studies, preliminary nature of studies showing effectiveness, the lack of adequate study on their safety, and reports of
eosinophilia–myalgia syndrome from contaminated tryptophan in 1989 and 1990, the use of tryptophan and 5-HTP is not highly recommended or thought to be clinically useful. ==Medical devices==