Antidepressant Medications: Pharmacological Properties and Evidence for Acute-Phase Efficacy
Key points
- Many strategies have been applied to the classification of antidepressant drugs, including systems based on the perceived behavioral effects of different drugs, the severity of depression (Paykel 1990), and the drugs' chemical structures (Klein and Davis 1969).
- The traditional method involves the distinction between monoamine oxidase inhibitors (MAOIs) and tricyclic antidepressants (TCAs).
- This system has used pharmacological effects to define the former and chemical structure to define the latter.
- The advent of new medications that do not fall into either of these groups and increased knowledge regarding the pharmacological effects that are more important to the efficacy of current antidepressants have highlighted the inconsistencies in earlier approaches.
Antidepressant Medications: Pharmacological Properties and Evidence for Acute-Phase Efficacy
Classification of Antidepressant Drugs and Overview of Their Mechanism of Action
Many strategies have been applied to the classification of antidepressant drugs, including systems based on the perceived behavioral effects of different drugs, the severity of depression (Paykel 1990), and the drugs' chemical structures (Klein and Davis 1969). The traditional method involves the distinction between monoamine oxidase inhibitors (MAOIs) and tricyclic antidepressants (TCAs). This system has used pharmacological effects to define the former and chemical structure to define the latter. The advent of new medications that do not fall into either of these groups and increased knowledge regarding the pharmacological effects that are more important to the efficacy of current antidepressants have highlighted the inconsistencies in earlier approaches.
Most effective antidepressants potently increase synaptic levels of norepinephrine (NE) and/or serotonin (5-hydroxytryptamine [5-HT]) and in some cases dopamine (DA). Most accomplish this by inhibiting reuptake of monoamines (NE, DA, and serotonin) or inhibiting the enzyme monoamine oxidase (MAO). It has not been clear whether this increase in synaptic monoamine levels is the primary mechanism or even a necessary part of the mechanism of antidepressant action, because synaptic levels increase within hours of the first dose, but therapeutic response does not usually begin until 1-2 weeks later. This lack of temporal relationship between increased synaptic monoamine levels and clinical response led to a search for other effects that correlate more closely with therapeutic response.
Antidepressant and Antimanic Medications Introduction Diagnostic Indications and Contraindications
Written and revised by
Gerald Hurowitz, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
health.am provides general information, not medical advice. Always consult a qualified health professional about your own health.
Explore health topics
More in this topic
Mental Health →NewsIntranasal ketamine confers rapid antidepressant effect in depression
A research team from the Icahn School of Medicine at Mount Sinai published the first controlled evidence showing that an intranasal ketamine spray conferred an unusually rapid antidepressant effect –within 24 hours- and…
9 April 2014
NewsStudy finds no evidence that vitamin D supplements reduce depression
Vitamin D deficiency has been implicated in numerous health conditions in recent years, including depressed mood and major depressive disorder. Recent observational studies provide some support for an association of…
19 March 2014
NewsPrimary care practitioners hesitate to prescribe antidepressants for depressed teens
Pediatric primary care practitioners (PCPs) are reluctant to prescribe antidepressant medications to adolescent patients - even those with severe depression, reports a study in the January Journal of Developmental &…
