What is depression?|
Depression is a normal reaction to grievous loss. However, some people have a tendency to suffer depression far worse than the situation would indicate. Clinical depression refers to an extreme state of lowered mood, often accompanied by disturbances of sleep, energy, appetite, concentration, interest and libido. Depression may arise following stressful life events (reactive depression), however most often it arises without detectable external influences (endogenous depression).
Pathology of depression
Research indicates that low levels of chemicals which carry signals from one nerve cell to another, particularly norepinephrine(noradrenaline) and serotonin in the brain, are the biological cause of the disorder. These neurotransmitters are involved in the functioning of the hypothalamus, which helps to regulate sleep, appetite, sexuality and physical movement.
Depression is a common and highly treatable disorder, with most patients returning to pre-depression levels of functioning after treatment. Proper treatment relieves symptoms in 80-90% of patients. Patients with depression must be carefully assessed for the presence of other psychiatric or medical disorders, as well as psychosocial stresses in their lives. Beyond diagnosis, treatment consists of patient education and support, evaluation of the risk of suicide, and treatment of symptoms with antidepressant medication, psychotherapy, or both.
Antidepressant drugs are medicines that relieve the symptoms of mental depression. A wide range of antidepressants is available, including tricyclic antidepressants, selective serotonin re-uptake inhibitors (SSRI), monoamine oxidase inhibitors (MAOI), selective norepinephrine re-uptake inhibitors (SNRI), and heterocyclic drugs. Most of these medications are in the form of tablets or capsules, that are taken orally in recommended doses.
All available antidepressants have been found effective in the treatment of mild-to-moderate depression. The choice of which agent to use in any particular case is based primarily on the side-effect profile of the drug and how it would effect the patient. Women, elderly patients and children may achieve higher plasma concentrations of antidepressants and thus may require lower dosages of these medications.
Although these drugs are usually effective against depression, it takes 1-2 weeks for the effects to be noticeable in the patient, yet many adverse side effects are apparent much quicker. Antidepressant drugs can also be used to treat other conditions, such as obsessive compulsive disorder, premenstrual syndrome, chronic pain and eating disorders.
If the patient has not responded to antidepressant medication, in cases of major depression, or if the patient is becoming dehydrated, extremely suicidal or psychotic, electroconvulsive therapy may be indicated. This is administered under anaesthesia and modified by muscle relaxant drugs. An example of alternative treatment for depression is St John's wort, used extensively in Europe.
MARIs eg nortriptyline and amitriptyline.
Tricyclic drugs are monoamine re-uptake inhibitors (MARI). They are so named because their chemical structures include a three-ring chain. They block the pre-synaptic (a synapse is the junction between two neurones) re-uptake of both serotonin and norepinephrine. Pre-synaptic re-uptake is the removal of the neurotransmitters by the neurone (nerve cell) that produced them before they have time to affect a second neurone, the post-synaptic neurone.
Thus the tricyclic antidepressants increase the levels of these two neurotransmitters in the brain (more molecules of neurotransmitter can affect the post-synaptic receptor sites).
Tricyclic drugs are the most frequently used antidepressant medication. They may achieve a better response in patients with severe depression or melancholic symptoms, and are more ef