Most antidepressants have a delayed onset of action and are usually taken over the course of weeks, months or years. They are generally considered distinct from stimulants, and drugs used for an immediate euphoric effect only are not generally considered antidepressants. Despite the name, antidepressants are often used in the treatment of other conditions, including anxiety disorders, bipolar disorder, obsessive compulsive disorder, eating disorders and chronic pain. Some have also become known as lifestyle drugs or "mood brighteners". Other medications not known as antidepressants, including antipsychotics in low doses and benzodiazepines, are also widely used to manage depression.

The term antidepressant is sometimes applied to any therapy (e.g. psychotherapy, electro-convulsive therapy, acupuncture) or process (e.g. sleep disruption, increased light levels, regular exercise) found to improve clinically depressed mood. An inert placebo tends to have a significant antidepressant effect, so establishing event at the same time that an antidepressant in a clinical trial involves demonstrating a significant additional effect.
History

In attempting to improve the effectiveness of common of them, chlorpromazine, in conjunction with the Geigy pharmaceutical company, Kuhn discovered that compound "G 22355? (manufactured and patented in the US in 1951 by means of Hafliger and Schinder) had a beneficial effect in patients with depression with mental and motor retardation. He first reported his findings on what he called a "thymoleptic" (literally "taking hold of the emotions", by contrast with neuroleptics, "taking hold of the nerves") in 1955/56 and they gradually became established, resulting in the marketing of the first tricyclic antidepressant, imipramine, soon followed by variants.

Later history

These new drug therapies became prescription-only medications in the 1950s. It was estimated that no more than 50 to 100 people per million suffered from the kind of depression that these new drugs would treat and pharmaceutical companies were not earnest. Sales through the 1960s remained poor compared to the greater tranquilizers (neuroleptics/antipsychotics) and minor tranquilizers (such as benzodiazepines), which were being marketed for different uses.

The term antidepressant is reported to have been coined by Lurie and to not acquire been widely adopted until at least the 1960s. Imipramine remained in common use and numerous successors were introduced. The field of MAO inhibitors remained quietness for many years until "reversible" forms affecting only the MAO-A subtype were introduced, avoiding more of the adverse effects.

Most pharmacologists by the 1960s conclusion the main therapeutic action of tricyclics was to inhibit norepinephrine reuptake, but it was gradually observed that this action was associated by energizing and motor stimulating personal estate whilst some antidepressant compounds appeared to hold differing effects through action on serotonin systems (notably proposed by Carlsson and Lindqvist (1969) and Lapin and Oxenkrug (1969)).

Researchers began a process of rational mix with drugs design to lay by itself antihistamine-derived compounds that would "selectively" (specifically) target these systems. The first such compound to be patented, in 1971, was zimelidine, whilst the first released clinically was indalpine. Fluoxetine (Prozac), FDA approved for commercial conversion to one act in 1988, became the first blockbuster SSRI. Fluoxetine was developed at Eli Lilly in the seasonably 1970s by Bryan Molloy, David Wong and others.

Types of Antidepressants

Selective serotonin reuptake inhibitors (SSRIs) are a family of antidepressants considered to be the current standard of drug treatment. It is thought that one cause of depression is an inadequate amount of serotonin, a chemical used in the brain to transmit signals between neurons. SSRIs are uttered to work by preventing the reuptake of serotonin by the presynaptic nerve, thus maintaining higher levels of 5-HT in the synapse. Recently, however, work by two researchers has called into question the link between serotonin deficiency and symptoms of depression, noting that the efficacy of SSRIs considered in the state of treatment does not in itself prove the link. Recent inquiry indicates that these drugs may interact with transcription factors known as "clock genes", which may be important for the addictive properties of drugs of abuse, and possibly in obesity.