Difficulty concentrating, remembering, making decisions. Persistent physical symptoms that do not respond to treatment, such as headaches, digestive disorders, and chronic pain.

Types of depression : Depressive disorders come in different forms, just as do other illnesses, such as heart disease and diabetes. Three of the most common types of depressive disorders are discussed below. However, remember that within each of these types, there are variations in the number, severity, and persistence of symptoms. Major depression is characterized by a combination of symptoms, including sad mood (see symptom list), that interfere with the ability to work, sleep, eat, and enjoy once-pleasurable activities. Disabling episodes of depression can occur once, twice, or several times in a lifetime. Dysthymia is a less severe type of depression. It involves long-term (chronic) symptoms that do not disable, but yet prevent the affected person from functioning at "full steam" or from feeling good. Sometimes, people with dysthymia also experience episodes of major depression. This combination of the two types of depression is referred to as double-depression. Another type of depression is bipolar disorder, which was formerly called manic-depressive illness or manic depression. This condition shows a particular pattern of inheritance. Not nearly as common as the other types of depressive disorders, bipolar disorder involves cycles of depression and mania, or elation. Bipolar disorder is often a chronic, recurring condition. Sometimes, the mood switches are dramatic and rapid, but most often they are gradual. When in the depressed cycle, the person can experience any or all of the symptoms of a depressive disorder. When in the manic cycle, any or all of the symptoms listed under mania may be experienced. Mania often affects thinking, judgment, and social behavior in ways that cause serious problems and embarrassment. For example, unwise business or financial decisions may be made when an individual is in a manic phase.

Treatments are available for depression - Antidepressant Medications : Selective serotonin reuptake inhibitors (SSRIs) are medications that increase the amount of the neurochemical serotonin in the brain. (Remember that brain serotonin levels are low in depression.) As their name implies, the SSRIs work by selectively inhibiting (blocking) serotonin reuptake in the brain. This block occurs at the synapse, the place where brain cells (neurons) are connected to each other. Serotonin is one of the chemicals in the brain that carries messages across these connections (synapses) from one neuron to another. The SSRIs work by keeping the serotonin present in high concentrations in the synapses. These drugs do this by preventing the reuptake of serotonin back into the sending nerve cell. The reuptake of serotonin is responsible for turning off the production of new serotonin. Therefore, the serotonin message keeps on coming through. This, in turn, helps arouse (activate) cells that have been deactivated by depression, and relieves the depressed person's symptoms. In the United States, SSRIs have been used successfully for a decade to treat depression. They have fewer side effects than the tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors (MAOIs), which are discussed below. SSRIs do not interact with the chemical tyramine in foods, as do the MAOIs. Also, SSRIs do not cause orthostatic hypotension and heart rhythm disturbances, like the TCAs do. Therefore, SSRIs are often the first-line treatment for depression. Examples of SSRIs include fluoxetine (Prozac), paroxetine (Paxil), sertraline (Zoloft), citalopram (Celexa), and fluvoxamine (Luvox). SSRIs are generally well tolerated and side effects are usually mild. The most common side effects are nausea, diarrhea, agitation, insomnia, and headache. However, these side effects generally go away within the first month of SSRI use. Some patients experience sexual side effects, such as decreased sexual desire (decreased libido), delayed orgasm, or an inability to have an orgasm. Some patients experience tremors with SSRIs. The so-called serotonergic (meaning caused by serotonin) syndrome is a serious neurologic condition associated with the use of SSRIs. It is characterized by high fevers, seizures, and heart rhythm disturbances. This condition is very rare and has been reported only in very ill psychiatric patients taking multiple psychiatric medications. All patients are unique biochemically. Therefore, the occurrence of side effects or the lack of a satisfactory result with one SSRI does not mean that another medication in this group will not be beneficial. However, if someone in the patient's family has had a positive response to a particular drug, that drug would be the preferable one to try first. Dual Action Antidepressants : The biochemical reality is that all classes of medications that treat depression (MAOIs, SSRIs, TCAs, and atypical antidepressants) have some effect on both norepinephrine and serotonin, as well as on other neurotransmitters. However, the various medications affect the different neurotransmitters in varying degrees. Some of the newer antidepressant drugs, however, appear to have particularly robust effects on both the norepinephrine and serotonin systems. These drugs seem to be very promising, especially for the more severe and chronic cases of depression. (Psychiatrists, rather than family practitioners, see such cases most frequently.) Venlafaxine (Effexor) is one of these dual action compounds. It is a serotonin reuptake inhibitor that, at lower doses, shares many of the safety and low side effect characteristics of the SSRIs. At higher doses, this drug appears to block the reuptake of norepinephrine. Thus, venlafaxine can be considered an SNRI, a serotonin and norepinephrine reuptake inhibitor. Another newer antidepressant, mirtazapine (Remeron), is a tetracyclic compound (four-ring chemical structure). It works at somewhat different biochemical sites and in different ways than the other drugs. It affects serotonin, but at a post-synaptic site (after the connection between nerve cells.) It also increases histamine levels, which can cause drowsiness. For this reason, mirtazapine is given at bedtime and is often prescribed for people who have trouble falling asleep. Like venlafaxine, it also works by increasing levels in the norepinephrine system. Other than causing sedation, this medication has side effects that are similar to those of the SSRIs, but to a lesser degree in many cases. Atypical antidepressants are so named because they work in a variety of ways. Thus, atypical antidepressants are not TCAs or SSRIs, but they act like them. More specifically, they increase the level of certain neurochemicals in the brain synapses (where nerves communicate with each other). Examples of atypical antidepressants include nefazodone (Serzone), trazodone (Desyrel), venlafaxine (Effexor), and bupropion (Wellbutrin). The United States Food and Drug Administration (FDA) has also approved bupropion for use in weaning from addiction to cigarettes. This drug is also being studied for treating attention deficit disorder (ADD) or attention deficit hyperactivity disorder (ADHD). These problems affect many children and adults and restrict their ability to focus or concentrate on one thing at a time.

Symptoms of depression and mania : Not everyone who is depressed or manic experiences every symptom. Some people experience a few symptoms and some many symptoms. The severity of symptoms also varies with individuals. Depression Symptoms of Manic Depression : Persistently sad, anxious, or "empty" mood. Feelings of hopelessness, pessimism. Feelings of guilt, worthlessness, helplessness. Loss of interest or pleasure in hobbies and activities that were once enjoyed, including sex. Insomnia, early-morning awakening, or oversleeping. Decreased appetite and/or weight loss, or overeating and weight gain. Fatigue, decreased energy, being "slowed down." Thoughts of death or suicide, suicide attempts. Restlessness, irritability.