Focus is increasing on prevention of anxiety disorders. There is tentative evidence to support the use of cognitive behavior therapy and mindfulness therapy. As of 2013, there are no effective measures to prevent GAD in adults.

Selective serotonin reuptake inhibitors (SSRIs), a class of antidepressants, are first choice medication for generalized social phobia but a second line treatment. Compared to older forms of medication, there is less risk of tolerability and drug dependency associated with SSRIs.

In a 1995 double-blind, placebo-controlled trial, the SSRI paroxetine was shown to result in clinically meaningful improvement in 55 percent of patients with generalized social anxiety disorder, compared with 23.9 percent of those taking placebo. An October 2004 study yielded similar results. Patients were treated with either fluoxetine, psychotherapy, or a placebo. The first four sets saw improvement in 50.8 to 54.2 percent of the patients. Of those assigned to receive only a placebo, 31.7 percent achieved a rating of 1 or 2 on the Clinical Global Impression-Improvement scale. Those who sought both therapy and medication did not see a boost in improvement.

General side-effects are common during the first weeks while the body adjusts to the drug. Symptoms may include headaches, nausea, insomnia and changes in sexual behavior. Treatment safety during pregnancy has not been established. In late 2004 much media attention was given to a proposed link between SSRI use and suicidality [a term that encompasses suicidal ideation and attempts at suicide as well as suicide]. For this reason, [although evidential causality between SSRI use and actual suicide has not been demonstrated] the use of SSRIs in pediatric cases of depression is now recognized by the Food and Drug Administration as warranting a cautionary statement to the parents of children who may be prescribed SSRIs by a family doctor. Recent studies have shown no increase in rates of suicide. These tests, however, represent those diagnosed with depression, not necessarily with social anxiety disorder.

In addition, studies show that more socially phobic patients treated with anti-depressant medication develop hypomania than non-phobic controls. The hypomania can be seen as the medication creating a new problem.

Other prescription drugs are also used, if other methods are not effective. Before the introduction of SSRIs, monoamine oxidase inhibitors (MAOIs) such as phenelzine were frequently used in the treatment of social anxiety. Evidence continues to indicate that MAOIs are effective in the treatment and management of social anxiety disorder and they are still used, but generally only as a last resort medication, owing to concerns about dietary restrictions, possible adverse drug interactions and a recommendation of multiple doses per day. A newer type of this medication, Reversible inhibitors of monoamine oxidase subtype A (RIMAs) such as the drug moclobemide, bind reversibly to the MAO-A enzyme, greatly reducing the risk of hypertensive crisis with dietary tyramine intake.

Benzodiazepines such as clonazepam are an alternative to SSRIs. These drugs are often used for short-term relief of severe, disabling anxiety. Although benzodiazepines are still sometimes prescribed for long-term everyday use in some countries, there is concern over the development of drug tolerance, dependency and misuse. It has been recommended that benzodiazepines be considered only for individuals who fail to respond to other medications. Benzodiazepines augment the action of GABA, the major inhibitory neurotransmitter in the brain; effects usually begin to appear within minutes or hours. In most patients, tolerance rapidly develops to the sedative effects of benzodiazepines, but not to the anxiolytic effects. Long-term use of benzodiazepine may result in physical dependence, and abrupt discontinuation of the drug should be avoided due to high potential for withdrawal symptoms (including tremor, insomnia, and in rare cases, seizures). A gradual tapering of the dose of clonazepam (a decrease of 0.25 mg every 2 weeks), however, has been shown to be well tolerated by patients with social anxiety disorder. Benzodiazepines are not recommended as monotherapy for patients who have major depression in addition to social anxiety disorder and should be avoided in patients with a history of substance abuse.

Certain anticonvulsant drugs such as gabapentin are effective in social anxiety disorder and may be a possible treatment alternative to benzodiazepines.

Serotonin-norepinephrine reuptake inhibitors (SNRIs) such as venlafaxine have shown similar effectiveness to the SSRIs. In Japan, Milnacipran is used in the treatment of Taijin kyofusho, a Japanese variant of social anxiety disorder. The atypical antidepressants mirtazapine and bupropion have been studied for the treatment of social anxiety disorder, and rendered mixed results.

Some people with a form of social phobia called performance phobia have been helped by beta-blockers, which are more commonly used to control high blood pressure. Taken in low doses, they control the physical manifestation of anxiety and can be taken before a public performance.

A novel treatment approach has recently been developed as a result of translational research. It has been shown that a combination of acute dosing of d-cycloserine (DCS) with exposure therapy facilitates the effects of exposure therapy of social phobia. DCS is an old antibiotic medication used for treating tuberculosis and does not have any anxiolytic properties per se. However, it acts as an agonist at the glutamatergic N-methyl-D-aspartate (NMDA) receptor site, which is important for learning and memory.

Kava-kava has also attracted attention as a possible treatment, although safety concerns exist.

Lifestyle changes include exercise, for which there is moderate evidence for some improvement, regularizing sleep patterns, reducing caffeine intake, and stopping smoking. Stopping smoking has benefits in anxiety as large as or larger than those of medications.

The use of medication is applied in extreme cases of SAD when other treatment options have been utilized and failed. However, it has been difficult to prove the benefits of drug treatment in patients with SAD because there have been many mixed results. Despite all the studies and testings, there has yet to be a specific medication for SAD. Medication prescribed for adults from the Food and Drug Administration (FDA) are often used and have been reported to show positive results for children and adolescents with SAD.

There are mixed results regarding the benefits of using tricyclic antidepressants (TCAs), which includes imipramine and clomipramine. One study suggested that imipramine is helpful for children with “school phobia,” who also had an underlying diagnosis of SAD. However, other studies have also shown that imipramine and clomipramine had the same effect of children who were treated with the medication and placebo. The most promising medication is the use of selective serotonin reuptake inhibitors (SSRI) in adults and children. Several studies have shown that patients treated with fluvoxamine were significantly better than those treated with placebo. They showed decreasing anxiety symptoms with short-term and long-term use of the medication.

Non-medication based treatments are the first choice when treating individuals diagnosed with separation anxiety disorder. Counseling tends to be the best replacement for drug treatments. There are two different non-medication approaches to treat separation anxiety. The first is a psychoeducational intervention, often used in conjunction with other therapeutic treatments. This specifically involves educating the individual and their family so that they are knowledgeable about the disorder, as well as parent counseling and guiding teachers on how to help the child. The second is a psychotherapeutic intervention when prior attempts are not effective. Psychotherapeutic interventions are more structured and include behavioral, cognitive-behavioral, contingency, psychodynamic psychotherapy, and family therapy.

Cognitive behavioral therapy (CBT) has been shown to be effective in PMS and is suggested as a successful adjunct to SSRI treatment. CBT is an evidence-based treatment approach for treating depression and focuses on the link between mood, thoughts, and actions to help patients address current issues and symptoms. When CBT was compared to SSRI alone or in combination with SSRI, groups receiving CBT had significant improvement of PMS symptoms. Through the practice of CBT, patients are better able to recognize and modify recurrent issues as well as thought and behavior patterns that interfere with functioning well or that make depressive symptoms worse.

There have been some nutritional supplements that have been shown to help alleviate the symptoms of PMDD. In 1998, a placebo-controlled, randomized trial of 720 people with PMDD found that calcium carbonate demonstrated up to a 50% reduction in symptoms, compared with a 30% reduction in the control group. Herbal treatments that have shown promise in PMDD include chasteberry ("Vitex agnus castus"), St. John's wort ("Hypericum perforatum"), and ginkgo ("Ginkgo biloba)". Studies have been conducted on the efficacy of chasteberry and gingko, but as of this writing, no randomized controlled trial has been conducted on the efficacy of St. John's wort in alleviating PMDD symptoms.

The first line of pharmacotherapy is usually SSRIs due to their more tolerable nature and reduced side effects compared to the irreversible monoamine oxidase inhibitors or tricyclic antidepressants. Studies have found that the mean response to antidepressant medications for people with dysthymia is 55%, compared with a 31% response rate to a placebo. The most commonly prescribed antidepressants/SSRIs for dysthymia are escitalopram, citalopram, sertraline, fluoxetine, paroxetine, and fluvoxamine. It often takes an average of 6–8 weeks before the patient begins to feel these medications' therapeutic effects. Additionally, STAR*D, a multi-clinic governmental study, found that people with overall depression will generally need to try different brands of medication before finding one that works specifically for them. Research shows that 1 in 4 of those who switch medications get better results regardless of whether the second medication is an SSRI or some other type of antidepressant.

In a meta-analytic study from 2005, it was found that SSRIs and TCAs are equally effective in treating dysthymia. They also found that MAOIs have a slight advantage over the use of other medication in treating this disorder. However, the author of this study cautions that MAOIs should not necessarily be the first line of defense in the treatment of dysthymia, as they are often less tolerable than their counterparts, such as SSRIs.

Tentative evidence supports the use of amisulpride to treat dysthymia but with increased side effects.

A combination of antidepressant medication and psychotherapy has consistently been shown to be the most effective line of treatment for people diagnosed with dysthymia. Working with a psychotherapist to address the causes and effects of the disorder, in addition to taking antidepressants to help eliminate the symptoms, can be extremely beneficial. This combination is often the preferred method of treatment for those who have dysthymia. Looking at various studies involving treatment for dysthymia, 75% of people responded positively to a combination of cognitive behavioral therapy (CBT) and pharmacotherapy, whereas only 48% of people responded positively to just CBT or medication alone.

In a meta-analytic study from 2008, researchers found an effect size of -0.07 (Cohen's d) between pharmacologic treatments and psychological treatments for depressive disorders, suggesting pharmacologic treatments to be slightly more effective, though the results were not found to be statistically significant. This small effect is true only for SSRIs, with TCAs and other pharmacologic treatments showing no differences from psychological treatments. Additionally, there have been several studies yielding results that indicate that severe depression responds more favorably to psychotherapy than pharmacotherapy.

Treatments for classic (winter-based) seasonal affective disorder include light therapy, medication, ionized-air administration, cognitive-behavioral therapy and carefully timed supplementation of the hormone melatonin.

Photoperiod-related alterations of the duration of melatonin secretion may affect the seasonal mood cycles of SAD. This suggests that light therapy may be an effective treatment for SAD. Light therapy uses a lightbox which emits far more lumens than a customary incandescent lamp. Bright white "full spectrum" light at 10,000 lux, blue light at a wavelength of 480 nm at 2,500 lux or green (actually cyan or blue-green) light at a wavelength of 500 nm at 350 lux are used, with the first-mentioned historically preferred.

Bright light therapy is effective with the patient sitting a prescribed distance, commonly 30–60 cm, in front of the box with her/his eyes open but not staring at the light source for 30–60 minutes. A study published in May 2010 suggests that the blue light often used for SAD treatment should perhaps be replaced by green or white illumination. Discovering the best schedule is essential. One study has shown that up to 69% of patients find lightbox treatment inconvenient and as many as 19% stop use because of this.

Dawn simulation has also proven to be effective; in some studies, there is an 83% better response when compared to other bright light therapy. When compared in a study to negative air ionization, bright light was shown to be 57% effective vs. dawn simulation 50%. Patients using light therapy can experience improvement during the first week, but increased results are evident when continued throughout several weeks. Most studies have found it effective without use year round but rather as a seasonal treatment lasting for several weeks until frequent light exposure is naturally obtained.

Light therapy can also consist of exposure to sunlight, either by spending more time outside or using a computer-controlled heliostat to reflect sunlight into the windows of a home or office. Although light therapy is the leading treatment for seasonal affective disorder, prolonged direct sunlight or artificial lights that don't block the ultraviolet range should be avoided due to the threat of skin cancer.

SSRI (selective serotonin reuptake inhibitor) antidepressants have proven effective in treating SAD. Effective antidepressants are fluoxetine, sertraline, or paroxetine. Both fluoxetine and light therapy are 67% effective in treating SAD according to direct head-to-head trials conducted during the 2006 Can-SAD study. Subjects using the light therapy protocol showed earlier clinical improvement, generally within one week of beginning the clinical treatment. Bupropion extended-release has been shown to prevent SAD for one in eight people, but has not been compared directly to other preventive options in trials.

Negative air ionization, which involves releasing charged particles into the sleep environment, has been found effective with a 47.9% improvement if the negative ions are in sufficient density (quantity).

Depending upon the patient, one treatment (e.g., lightbox) may be used in conjunction with another (e.g., medication).

Modafinil may be an effective and well-tolerated treatment in patients with seasonal affective disorder/winter depression.

Another explanation is that vitamin D levels are too low when people do not get enough Ultraviolet-B on their skin. An alternative to using bright lights is to take vitamin D supplements. However, studies did not show a link between vitamin D levels and depressive symptoms in elderly Chinese nor among elderly British women.

Physical exercise has shown to be an effective form of depression therapy, particularly when in addition to another form of treatment for SAD. One particular study noted marked effectiveness for treatment of depressive symptoms when combining regular exercise with bright light therapy. Patients exposed to exercise which had been added to their treatments in 20 minutes intervals on the aerobic bike during the day along with the same amount of time underneath the UV light were seen to make quick recovery.

Winter depression is a common slump in the mood of some inhabitants of most of the Nordic countries. It was first described by the 6th century Goth scholar Jordanes in his "Getica" wherein he described the inhabitants of Scandza (Scandinavia). Iceland, however, seems to be an exception. A study of more than 2000 people there found the prevalence of seasonal affective disorder and seasonal changes in anxiety and depression to be unexpectedly "low" in both sexes. The study's authors suggested that propensity for SAD may differ due to some genetic factor within the Icelandic population. A study of Canadians of wholly Icelandic descent also showed low levels of SAD. It has more recently been suggested that this may be attributed to the large amount of fish traditionally eaten by Icelandic people, in 2007 about 90 kilograms per person per year as opposed to about 24 kg in the US and Canada, rather than to genetic predisposition; a similar anomaly is noted in Japan, where annual fish consumption in recent years averages about 60 kg per capita. Fish are high in vitamin D. Fish also contain docosahexaenoic acid (DHA), which help with a variety of neurological dysfunctions.

The controversy over the use of antidepressants began in 2003 when Great Britain's Department of Health stated that, based on data collected by the Medicines and Healthcare products Regulatory Agency, paroxetine (an antidepressant) should not be used on patients under the age of 18. Since then, the United States Food and Drug Administration (FDA) has issued a warning describing the increased risk of adverse effects of antidepressants used as treatment in those under the age of 18. The main concern is whether the risks outweigh the benefits of the treatment. In order to decide this, studies often look at the adverse effects caused by the medication in comparison to the overall symptom improvement. While multiple studies have shown an improvement or efficacy rate of over 50 percent, the concern of severe side effects – such as suicidal ideation or suicidal attempts, worsening of symptoms, or increase in hostility – are still concerns when using antidepressants. However, an analysis of multiple studies argues that while the risk of suicidal ideation or attempt is present, the benefits significantly outweigh the risks. Due to the variability of these studies, it is currently recommended that if antidepressants are chosen as a method of treatment for children or adolescents, the clinician monitor closely for adverse symptoms, since there is still no definitive answer on the safety and overall efficacy.

Among the psychological assessments for identifying whether or not children and adolescents are experiencing depression and/or depressive symptoms is the Children's Depression Inventory. In early 2016, the USPSTF released an updated recommendation for the screening of adolescents ages 12 to 18 years for major depressive disorder (MDD). Appropriate treatment and follow-up should be provided for adolescents who screen positive.

Treatment of minor depressive disorder has not been studied as extensively as major depressive disorder. Although there are often similarities in the treatments used, there are also differences in what may work better for the treatment of minor depressive disorder. Some third-party payers do not pay to cover treatment for minor depressive disorder.

The leading treatment techniques for minor depressive disorder are the use of antidepressants and therapy. Typically, patients with minor depression were treated by watchful waiting, prescribed antidepressants, and given brief supportive counseling, but Problem-Solving Treatment for Primary Care (PST-PC) is a Cognitive-Behavioral Therapy that has gained popularity. In one study, Problem-Solving Treatment for Primary Care (PST-PC) and Paroxetine, an antidepressant, were shown to be equally effective in significantly reducing symptoms. In another study, PST-PC was compared with the more typical care of the time and shown to reduce symptoms more quickly. Although the use of antidepressants has been widely used, not all agree that it is an appropriate treatment for some minor depression disorder settings.

Another alternative that has been researched is the use of St. John's wort ("Hypericum perforatum"). This herbal treatment has been studied by various groups with various results. Some studies show evidence of the treatment being helpful to treat minor depression, but others show that it does no better than the placebo.

Preventative efforts may result in decreases in rates of the condition of between 22 and 38%. Eating large amounts of fish may also reduce the risk.

Behavioral interventions, such as interpersonal therapy and cognitive-behavioral therapy, are effective at preventing new onset depression. Because such interventions appear to be most effective when delivered to individuals or small groups, it has been suggested that they may be able to reach their large target audience most efficiently through the Internet.

However, an earlier meta-analysis found preventive programs with a competence-enhancing component to be superior to behavior-oriented programs overall, and found behavioral programs to be particularly unhelpful for older people, for whom social support programs were uniquely beneficial. In addition, the programs that best prevented depression comprised more than eight sessions, each lasting between 60 and 90 minutes, were provided by a combination of lay and professional workers, had a high-quality research design, reported attrition rates, and had a well-defined intervention.

The Netherlands mental health care system provides preventive interventions, such as the "Coping with Depression" course (CWD) for people with sub-threshold depression. The course is claimed to be the most successful of psychoeducational interventions for the treatment and prevention of depression (both for its adaptability to various populations and its results), with a risk reduction of 38% in major depression and an efficacy as a treatment comparing favorably to other psychotherapies.

Psychotherapy can be delivered, to individuals, groups, or families by mental health professionals. A 2015 review found that cognitive behavioral therapy appears to be similar to antidepressant medication in terms of effect. A 2012 review found psychotherapy to be better than no treatment but not other treatments. With more complex and chronic forms of depression, a combination of medication and psychotherapy may be used. A 2014 Cochrane review found that work-directed interventions combined with clinical interventions helped to reduce sick days taken by people with depression.

Psychotherapy has been shown to be effective in older people. Successful psychotherapy appears to reduce the recurrence of depression even after it has been terminated or replaced by occasional booster sessions.

When treating addictive personalities, the primary or presenting addiction needs to be treated first. Only once the behavior is under control can the person truly begin to do any of the therapeutic work necessary for recovery.

Common forms of treatment for addictive personalities include cognitive behavioral therapy, as well as other behavioral approaches. These treatments help patients by providing healthy coping skills training, relapse prevention, behavior interventions, family and group therapy, facilitated self-change approaches, and aversion therapy. Behavioral approaches include using positive reinforcement and behavioral modeling. Along with these, other options that help with treating those who suffer with addictive personality include social support, help with goal direction, rewards, enhancing self-efficacy and help teaching coping skills.

Another important skill to learn in treatment, which can be overlooked, is self-soothing. People with addictive personalities use their addictions as coping mechanisms when in stressful situations. However, since their addictions do not actually soothe them, so much as they provide momentary relief from anxiety or uncomfortable emotions, these individuals feel the need to use their addiction more often. Thus, self-soothing and other mindfulness-based interventions can be used for treatment because they provide healthier coping mechanisms once the addictive behavior has been removed. These strategies relate to the use of dialectical behavior therapy, another useful technique. DBT provides ways to tolerate distress and regulate emotions, both of which are challenging to someone with an addictive personality. DBT may not be the most effective treatment for all substance abusers, but there is evidence that it is helpful for most alcoholics and addicts, as well as in eating disorders, and those with co-occurring conditions.

Another form of treatment that has been considered for people with addictive personalities who tend towards substance abuse is medication. A medication called Disulfiram was created in 1947. This pill was used for alcoholics and would cause adverse effects if combined with alcohol. This medication is still used today but two others have been made to help treat alcohol dependence (Acamprosate and Naltrexone). Along with alcohol addictions, Naltrexone is also used for opioid addiction.

Although these medications have proven results in decreasing heavy drinking, doctors still have to consider the patients' health and the risky side effects when prescribing these medications.

Minor depressive disorder, also known as minor depression, is a mood disorder that does not meet the full criteria for major depressive disorder but at least two depressive symptoms are present for two weeks. These symptoms can be seen in many different psychiatric and mental disorders, which can lead to more specific diagnoses of an individual's condition. However, some of the situations might not fall under specific categories listed in the "Diagnostic and Statistical Manual of Mental Disorders". Minor depressive disorder is an example of one of these nonspecific diagnoses, as it is a disorder classified in the DSM-IV-TR under the category Depressive Disorder Not Otherwise Specified (DD-NOS). The classification of NOS depressive disorders is up for debate. Minor depressive disorder as a term was never an officially accepted term, but was listed in Appendix B of the DSM-IV-TR. This is the only version of the DSM that contains the term, as the prior versions and the most recent edition, DSM-5, does not mention it.

A person is considered to have minor depressive disorder if they experience 2 to 4 depressive symptoms, with one of them being either depressed mood or loss of interest or pleasure, during a 2-week period. The person must not have experienced the symptoms for 2 years and there must not have been one specific event that caused the symptoms to arise. Although not all cases of minor depressive disorder are deemed in need of treatment, some cases are treated similarly to major depressive disorder. This treatment includes cognitive behavioral therapy (CBT), anti-depressant medication, and combination therapy. A lot of research supports the notion that minor depressive disorder is an early stage of major depressive disorder, or that it is simply highly predictive of subsequent major depressive disorder.

Psychologic therapies are recommended for elderly patients with depression because of this group’s vulnerability to adverse effects and high rates of medical problems and medication use. Psychotherapeutic approaches include cognitive behavioral therapy, supportive psychotherapy, problem-solving therapy, and interpersonal therapy. The potential benefit of psychotherapy is not diminished by increasing age. Older adults often have better treatment compliance, lower dropout rates, and more positive responses to psychotherapy than younger patients. Consultation with a clinical geropsychologist is useful.

Pharmacotherapy for acute episodes of depression usually is effective and free of complications. Underuse or misuse of antidepressants and prescribing inadequate dosages are the most common mistakes physicians make when treating elderly patients for depression. Only 10 to 40 percent of depressed elderly patients are given medication. Antidepressants, in general, may also work by playing a neuroprotective role in how they relieve anxiety and depression. It's thought that antidepressants may increase the effects of brain receptors that help nerve cells keep sensitivity to glutamate which is an organic compound of a nonessential amino acid. This increased support of nerve cells lowers glutamate sensitivity, providing protection against the glutamate overwhelming and exciting key brain areas related to depression. Antidepressant medications are often the first treatment choice for adults with moderate or severe depression, sometimes along with psychotherapy. Although antidepressants may not cure depression, they can lead to remission, which is the disappearance or nearly complete reduction of depression symptoms.

Non-pharmaceutical therapies can also help those with the illness. These include cognitive behavioral therapy (CBT), psychodynamic therapy, psychoanalysis, social rhythm therapy, interpersonal therapy, behavioral therapy, cognitive therapy, art therapy, music therapy, psychoeducation, mindfulness, light therapy, and family-focused therapy. Relapse can still occur, even with continued medication and therapy.

The most common treatment for reducing bipolar II disorder symptoms is medication, usually in the form of mood stabilizers. However, treatment with mood stabilizers may produce a flat affect in the patient, which is dose-dependent. Concurrent use of SSRI antidepressants may help some with bipolar II disorder, though these medications should be used with caution because it is believed that they may cause a hypomanic switch.

The pharmaceutical management of bipolar II disorder is not generally supported by strong evidence, with limited randomised controlled trials (RCTs) published in the literature. Some medications used are:

- Lithium - There is strong evidence that lithium is effective in treating both the depressive and hypomanic symptoms in bipolar II. In addition, its action as a mood stabilizer can be used to decrease the risk of hypomanic switch in patients treated with antidepressants.

- Anticonvulsants - there is evidence that lamotrigine decreases the risk of relapse in rapid cycling bipolar II. It appears to be more effective in bipolar II than bipolar I, suggesting that lamotrigine is more effective for the treatment of depressive rather than manic episodes. Doses ranging from 100–200 mg have been reported to have the most efficacy, while experimental doses of 400 mg have rendered little response. A large, multicentre trial comparing carbamazepine and lithium over two and a half years found that carbamazepine was superior in terms of preventing future episodes of bipolar II, although lithium was superior in individuals with bipolar I. There is also some evidence for the use of valproate and topiramate, although the results for the use of gabapentin have been disappointing.

- Antidepressants - there is evidence to support the use of SSRI and SNRI antidepressants in bipolar II. Indeed, some sources consider them to be one of the first line treatments. However, antidepressants also pose significant risks, including a switch to mania, rapid cycling, and dysphoria and so many psychiatrists advise against their use for bipolar. When used, antidepressants are typically combined with a mood stabilizer.

- Antipsychotics - there is good evidence for the use of quetiapine, and it has been approved by the FDA for this indication. There is also some evidence for the use of risperidone, although the relevant trial was not placebo controlled and was complicated by the use of other medications in some of the patients.

- Dopamine agonists - there is evidence for the efficacy of pramipexole from one RCT.

Depressed mood may not require professional treatment, and may be a normal temporary reaction to life events, a symptom of some medical condition, or a side effect of some drugs or medical treatments. A prolonged depressed mood, especially in combination with other symptoms, may lead to a diagnosis of a psychiatric or medical condition which may benefit from treatment. Different sub-divisions of depression have different treatment approaches.

In the United States, it has been estimated that two thirds of people with depression do not actively seek treatment. The World Health Organisation (WHO) has predicted that by 2030, depression will account for the highest level of disability accorded any physical or mental disorder in the world (WHO, 2008).

The UK National Institute for Health and Care Excellence (NICE) 2009 guidelines indicate that antidepressants should not be routinely used for the initial treatment of mild depression, because the risk-benefit ratio is poor. A recent meta-analysis also indicated that most antidepressants, besides fluoxetine, do not seem to offer a clear advantage for children and adolescents in the acute treatment of major depressive disorder.

A major depressive episode is a period characterized by the symptoms of major depressive disorder: primarily depressed mood for two weeks or more, and a loss of interest or pleasure in everyday activities, accompanied by other symptoms such as feelings of emptiness, hopelessness, anxiety, worthlessness, guilt and/or irritability, changes in appetite, problems concentrating, remembering details or making decisions, and thoughts of or attempts at suicide. Insomnia or hypersomnia, aches, pains, or digestive problems that are resistant to treatment may also be present. The description has been formalised in psychiatric diagnostic criteria such as the DSM-5 and ICD-10.

Significant emotional pain and economic costs are associated with depression. In the United States and Canada, the costs associated with major depression are comparable to those related to heart disease, diabetes, and back problems and are greater than the costs of hypertension. According to the Nordic Journal of Psychiatry, there is a direct correlation between major depressive episode and unemployment.

Treatments for a major depressive episode include exercise, psychotherapy and antidepressants, although in more serious cases, hospitalization or intensive outpatient treatment may be required.

There are many theories as to how depression occurs. One interpretation is that neurotransmitters in the brain are out of balance, and this results in feelings of worthlessness and despair. Magnetic resonance imaging shows that brains of people who have depression look different than the brains of people not exhibiting signs of depression. A family history of depression increases the chance of being diagnosed.