Both psychotherapy as well as different drugs (e.g. serotonin reuptake inhibitors - SSRIs or mood stabilizers, e.g. lithium, antiepileptics) have been suggested as treatments. However, no randomized controlled treatment trial of RBD has been conducted.

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.

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.

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.

There is some evidence that omega-3 fatty acids fish oil supplements containing high levels of eicosapentaenoic acid (EPA) to docosahexaenoic acid (DHA) are effective in the treatment of, but not the prevention of major depression. However, a Cochrane review determined there was insufficient high quality evidence to suggest Omega-3 fatty acids were effective in depression. There is limited evidence that vitamin D supplementation is of value in alleviating the symptoms of depression in individuals who are vitamin D deficient. There is some preliminary evidence that COX-2 inhibitors have a beneficial effect on major depression. Lithium appears effective at lowering the risk of suicide in those with bipolar disorder and unipolar depression to nearly the same levels as the general population. There is a narrow range of effective and safe dosages of lithium thus close monitoring may be needed. Low-dose thyroid hormone may be added to existing antidepressants to treat persistent depression symptoms in people who have tried multiple courses of medication. Limited evidence suggests stimulants such as amphetamine and modafinil may be effective in the short term, or as add on therapy.

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.

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.

Depression is a treatable illness. Treatments for a major depressive episode may be obtained in one or more of the following settings: mental health specialists (i.e. psychologist, psychiatrists, social workers, counselors, etc.), mental health centers or organizations, hospitals, outpatient clinics, social service agencies, private clinics, peer support groups, clergy, and employee assistance programs. The treatment plan could include psychotherapy alone, antidepressant medications alone, or a combination of medication and psychotherapy.

For major depressive episodes of severe intensity (multiple symptoms, minimal mood reactivity, severe functional impairment), combined psychotherapy and antidepressant medications are more effective than psychotherapy alone. Patients with severe symptoms may require outpatient treatment or hospitalization.

Psychotherapy, also known as talk therapy, counseling, or psychosocial therapy, is characterized by a patient talking about their condition and mental health issues with a trained therapist. Different types of psychotherapy can be effective for depression. These include cognitive behavioral therapy, interpersonal therapy, dialectical behavior therapy, acceptance and commitment therapy, and mindfulness techniques.

Medications used to treat depression include selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), norepinephrine-dopamine reuptake inhibitors (NDRIs), tricyclic antidepressants, monoamine oxidase inhibitors (MAOIs), and atypical antidepressants such as mirtazapine, which do not fit neatly into any of the other categories. Different antidepressants work better for different individuals. It is often necessary to try several before finding one that works best for a specific patient. Some people may find it necessary to combine medications, which could mean two antidepressants or an antipsychotic medication in addition to an antidepressant. If a person's close relative has responded well to a certain medication, that treatment will likely work well for him or her.

Sometimes, people stop taking antidepressant medications due to side effects, although side effects often become less severe over time. Suddenly stopping treatment or missing several doses may cause withdrawal-like symptoms. Some studies have shown that antidepressants may increase short-term suicidal thoughts or actions, especially in children, adolescents, and young adults. However, antidepressants are more likely to reduce a person's risk of suicide in the long run.

If left untreated, a typical major depressive episode may last for about six months. About 20% of these episodes can last two years or more. About half of depressive episodes end spontaneously. However, even after the major depressive episode is over, 20% to 30% of patients have residual symptoms, which can be distressing and associated with disability.

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.

It is proposed that ameliorating the stress response will allow neurotransmission to return to homeostasis. Anxiolytic medications that act as 5-HT receptor agonists (in particular, 5-HT1A) together with CRH and/or cortisol antagonists (which are implicated in the stress response) are hypothesized to be an appropriate method of achieving this therapeutic response. Psychological interventions can also help to raise the threshold for stress and thereby restore the stress response to normal.

There are different types of treatments available for mood disorders, such as therapy and medications. Behaviour therapy, cognitive behaviour therapy and interpersonal therapy have all shown to be potentially beneficial in depression. Major depressive disorder medications usually include antidepressants, while bipolar disorder medications can consist of antipsychotics, mood stabilizers, anticonvulsants and/or lithium. Lithium specifically has been proven to reduce suicide and all causes of mortality in people with mood disorders. If mitochondrial dysfunction or mitochondrial diseases are the cause of mood disorders like bipolar disorder, then it has been hypothesized that N-acetyl-cysteine (NAC), acetyl-L-carnitine (ALCAR), S-adenosylmethionine (SAMe), coenzyme Q10 (CoQ10), alpha-lipoic acid (ALA), creatine monohydrate (CM), and melatonin could be potential treatment options.

There have been a few studies of medications for treating PPD, however, the sample sizes were small, thus evidence is generally weak. Some evidence suggests that mothers with PPD will respond similarly to people with major depressive disorder. There is evidence which suggests that selective serotonin reuptake inhibitors (SSRIs) are effective treatment for PPD. However, a recent study has found that adding sertraline, an SSRI, to psychotherapy does not appear to confer any additional benefit. Therefore, it is not completely clear which antidepressants, if any, are most effective for treatment of PPD, and for whom antidepressants would be a better option than non-pharmacotherapy.

Some studies show that hormone therapy may be effective in women with PPD, supported by the idea that the drop in estrogen and progesterone levels post-delivery contribute to depressive symptoms. However, there is some controversy with this form of treatment because estrogen should not be given to people who are at higher risk of blood clots, which include women up to 12 weeks after delivery. Additionally, none of the existing studies included women who were breastfeeding.

Electroconvulsive therapy (ECT) has shown efficacy in women with severe PPD that have either failed multiple trials of medication-based treatment or cannot tolerate the available antidepressants.

As of 2013 it is unclear if acupuncture, massage, bright lights, or taking omega-3 fatty acids are useful.

Major depressive episodes may show comorbidity (association) with other physical and mental health problems. About 20-25% of individuals with a chronic general medical condition will develop major depression. Common comorbid disorders include: eating disorders, substance-related disorders, panic disorder, and obsessive-compulsive disorder. Up to 25% of people who experience a major depressive episode have a pre-existing dysthymic disorder.

Some persons who have a fatal illness or are at the end of their life may experience depression, although this is not universal.

A study on comorbidity of GAD and other depressive disorders has shown that treatment is not more or less effective when there is some sort of comorbidity of another disorder. The severity of symptoms did not affect the outcome of the treatment process in these cases.

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.

Pharmaceutical treatments for GAD include selective serotonin reuptake inhibitors (SSRIs). These are the preferred first line of treatment. SSRIs used for this purpose include escitalopram and paroxetine.

Common side effects include nausea, sexual dysfunction, headache, diarrhea, constipation, restlessness, increased risk of suicide in young adults and adolescents, among others. Overdose of an SSRI can result in serotonin syndrome.

CGD is relatively unresponsive to antidepressants or interpersonal psychotherapy; however, recent studies support the use of CG-targeted psychotherapy (similar to PTSD-targeted psychotherapy). Other methods of psycho-pharmacological treatment are under investigation.

Psychotherapy, more specifically, cognitive behavioral therapy (CBT), is the most widely used form of treatment for Somatic symptom disorder. In 2016, a randomized 12-week study suggested steady and significant improvement in health anxiety measures with cognitive behavioral therapy compared to the control group.

CBT can help in some of the following ways:

- Learn to reduce stress

- Learn to cope with physical symptoms

- Learn to deal with depression and other psychological issues

- Improve quality of life

- Reduce preoccupation with symptom

Moreover, brief psychodynamic interpersonal psychotherapy (PIT) for patients with multisomatoform disorder has shown its long-term efficacy for improving the physical quality of life in patients with multiple, difficult-to-treat, medically unexplained symptoms.

Antidepressant medication has also been used to treat some of the symptoms of depression and anxiety that are common among people who have somatic symptom disorder. Medications will not cure somatic symptom disorder, but can help the treatment process when combined with CBT.

Several studies have suggested that omega 3 fatty acids may have beneficial effects on depressive symptoms, but not manic symptoms. However, only a few small studies of variable quality have been published and there is not enough evidence to draw any firm conclusions.

The recommended treatment for adjustment disorder is psychotherapy. The goal of psychotherapy is symptom relief and behavior change. Anxiety may be presented as "a signal from the body" that something in the patient's life needs to change. Treatment allows the patient to put his or her distress or rage into words rather than into destructive actions. Individual therapy can help a person gain the support they need, identify abnormal responses and maximize the use of the individual's strengths. Counseling, psychotherapy, crisis intervention, family therapy, behavioral therapy and self-help group treatment are often used to encourage the verbalization of fears, anxiety, rage, helplessness, and hopelessness. Sometimes small doses of antidepressants and anxiolytics are used in addition to other forms of treatment. In patients with severe life stresses and a significant anxious component, benzodiazepines are used, although non-addictive alternatives have been recommended for patients with current or past heavy alcohol use, because of the greater risk of dependence. Tianeptine, alprazolam, and mianserin were found to be equally effective in patients with AD with anxiety. Additionally, antidepressants, antipsychotics (rarely) and stimulants (for individuals who became extremely withdrawn) have been used in treatment plans.

There has been little systematic research regarding the best way to manage individuals with an adjustment disorder. Because natural recovery is the norm, it has been argued that there is no need to intervene unless levels of risk or distress are high. However, for some individuals treatment may be beneficial. AD sufferers with depressive and/or anxiety symptoms may benefit from treatments usually used for depressive and/or anxiety disorders. One study found that AD sufferers received similar interventions to those with other psychiatric diagnoses, including psychological therapy and medication. Another study found that AD responded better than major depression to antidepressants. Given the absence of a meaningful evidence base for the treatment of AD "per se", watchful waiting should be considered initially; if symptoms are not improving or causing the sufferer marked distress then treatment should be directed at the predominating symptoms.

In addition to professional help, parents and caregivers can help their children with their difficulty adjusting by:

- offering encouragement to talk about his/her emotions

- offering support and understanding

- reassuring the child that their reactions are normal

- involving the child's teachers to check on their progress in school

- letting the child make simple decisions at home, such as what to eat for dinner or what show to watch on TV

- having the child engage in a hobby or activity they enjoy

Short courses of benzodiazepines may be used in addition to other medications until mood stabilizing become effective. Electroconvulsive therapy (ECT) is an effective form of treatment for acute mood disturbances in those with bipolar disorder, especially when psychotic or catatonic features are displayed. ECT is also recommended for use in pregnant women with bipolar disorder.

MD is supposed to be a common clinical phenomenon. According to some authors, masked depression is as frequent as overt depression. Although masked depression can be found at any age, it has been observed more commonly after mid-life.

Making the diagnosis and the management of MD in clinical practice are complicated by the fact that he who has got MD is unaware of his mental illness.

Patients with MD are reluctant to associate their physical symptoms with an affective disorder and refuse mental health care. As a rule, these patients attribute their disturbances to physical illness, seek medical care for them, and report only somatic complaints to their physicians, with the consequence that many of such depressions are not recognized or are misdiagnosed and mistreated Estimates of depressed patients who are correctly identified and treated range from 5% to 60%. Recent data show that about 10% of people who consult a physician for any reason originally suffer from affective disorders disguised by physical symptoms.

The lifetime prevalence of RBD has been estimated at 2.6 to 10.0%, and the one-year prevalence at 5.0-8.2%. The World Health Organization project on "Psychological problems in general health care", which was based on primary care samples, reported a one-year prevalence of 3.7 – 9.9%. However none of these studies differentiate between RBD with and without a history of other mood disorders (e.g. major depression). DSM-IV field trial estimated the life-time of RBD only to be about 2%.