In Japan, mood Disorder is managed by psychiatrys. Mood disorders are a family of psychiatric conditions defined by sustained disturbances in emotional state that impair functioning, including major depressive disorder, persistent depressive disorder (dysthymia), bipolar I and II disorders, cyclothymic disorder, premenstrual dysphoric disorder, and substance- or medical-condition-induced mood disorders. Globally, mood disorders affect roughly 280 million people; major depression alone affects 8.4% of US adults annually (NSDUH 2022) and is the leading cause of disability worldwide.
Mood disorders (ICD-10: F30-F39) comprise a DSM-5 diagnostic category of psychiatric conditions defined by sustained, clinically significant disturbance of mood that impairs functioning. The major subtypes are: major depressive disorder (single or recurrent episode of depressed mood plus neurovegetative symptoms for at least two weeks), persistent depressive disorder formerly dysthymia (chronic low-grade depression lasting at least two years in adults), bipolar I disorder (history of at least one manic episode), bipolar II disorder (at least one major depressive episode plus at least one hypomanic episode without full mania), cyclothymic disorder (chronic fluctuating subthreshold hypomanic and depressive symptoms for at least two years), premenstrual dysphoric disorder (cyclical luteal-phase mood disturbance), and substance- or medical-condition-induced mood disorder. Diagnosis follows DSM-5-TR criteria with full psychiatric history, mental status examination, and exclusion of medical contributors (thyroid disease, anemia, vitamin B12 deficiency, sleep apnea, medication side effects). The disorders share dysregulation of monoamine neurotransmitters, HPA axis hyperactivity, neuroinflammation, and altered limbic-cortical circuitry.
The key symptoms of Mood Disorder are: Persistent low or sad mood most of the day, nearly every day, that does not lift with positive events or distraction., Loss of interest or pleasure (anhedonia) in activities that previously brought enjoyment — hobbies, social contact, intimacy, work., Significant change in appetite or weight (5% or more in a month) without intentional dieting., Sleep disturbance including early morning awakening, frequent awakenings, or excessive sleep that does not feel restorative., Fatigue or loss of energy nearly every day even after adequate rest., Feelings of worthlessness or excessive, inappropriate guilt — guilt about past events that exceeds proportion to the actual circumstance., Difficulty concentrating, indecisiveness, or perceived slowing of thought that interferes with work or daily tasks..
Diagnosis follows DSM-5-TR criteria after comprehensive psychiatric assessment including detailed history of mood symptoms, family history, medical history, substance use, suicidality, and current functioning. The clinician distinguishes the specific mood disorder subtype because treatment differs substantially: bipolar disorder requires mood stabilizers rather than antidepressant monotherapy (which can precipitate manic switch). Validated rating scales support diagnosis and severity assessment: PHQ-9 for depression severity (≥10 suggests moderate depression, ≥20 severe), GAD-7 for comorbid anxiety, MDQ or Bipolar Spectrum Diagnostic Scale for bipolar screening, and Columbia Suicide Severity Rating Scale (C-SSRS) for suicide risk. Mental status examination notes appearance, behavior, speech, mood, affect, thought form and content, perceptual abnormalities, cognition, insight, and judgment. Medical workup excludes secondary causes: TSH and free T4, complete blood count, comprehensive metabolic panel, vitamin B12 and folate, vitamin D, urine toxicology in suspected substance involvement, and screening for sleep apnea when fatigue or hypersomnia predominates. Brain imaging is reserved for atypical presentations, first-onset psychosis, or focal neurological signs. Time course is critical: at least two weeks of symptoms is required for major depressive disorder, two years for persistent depressive disorder, seven days for mania, and four days for hypomania. Episodes are described as mild, moderate, severe, or with psychotic features, and bipolar mood disorders are tracked across the lifespan with mood charts. Differential diagnosis includes adjustment disorder, grief, anxiety disorders, ADHD, post-traumatic stress disorder, personality disorders, and secondary medical causes.
Prognosis varies by mood disorder subtype and adherence to treatment. Major depressive disorder remits with treatment in 60-80% of patients within 6-12 months when adequate therapy is matched to severity. Recurrence is common — 50% after one episode, 70% after two, 90% after three — so maintenance therapy after three or more episodes is recommended indefinitely. Bipolar disorder is a lifelong illness with episodic course; maintenance lithium reduces relapse by 50% and suicide risk by 60%. Persistent depressive disorder responds more slowly but improves with sustained combined treatment. Cyclothymic disorder often persists across the lifespan but rarely causes severe functional impairment. Untreated severe depression carries 15% lifetime suicide risk; bipolar disorder carries roughly 6-7% lifetime suicide risk, both substantially reduced by adequate treatment. Adverse prognostic factors include severe initial episode, psychotic features, comorbid substance use, chronic medical illness, early onset, and poor social support. Favorable factors include early treatment, adherence, social support, regular psychotherapy, and absence of substance use.
A psychiatrist should be involved when symptoms fail to remit on first-line antidepressant after 6-8 weeks at adequate dose, when bipolar disorder is suspected (any history of manic or hypomanic symptoms), when suicide risk is moderate to high, when psychosis is present, in pregnancy or postpartum mood disorders, when comorbid substance use complicates care, and in any first-onset severe depression. Primary care manages most uncomplicated mild-moderate depression effectively with appropriate stepped care and supervision.
Find specialists →Antidepressant response typically emerges over 2-4 weeks with full effect at 6-8 weeks. Psychotherapy benefits are usually evident at 4-8 weeks and continue developing over 12-20 sessions. Bipolar mood stabilizers take 2-4 weeks for full effect; lithium maintenance reduces relapse over the first 6-12 months. ECT shows response in 6-12 sessions over 3-4 weeks. Full functional recovery (returning to work, relationships, normal activities) typically occurs 2-6 months after symptomatic remission.
Aim for 150-300 minutes weekly of moderate aerobic activity, ideally including outdoor exposure to daylight. Resistance training 2-3 times weekly adds antidepressant benefit. Exercise improves mood, sleep, energy, and cognitive function. Even 10-15 minutes of walking helps when starting from inactivity. Engage in social or group exercise where possible to combine activity with connection.
Look for a board-certified psychiatrist or psychiatric nurse practitioner with experience in your specific mood disorder subtype (especially bipolar disorder, perinatal psychiatry, or treatment-resistant depression). Access to integrated psychotherapy (CBT, IPT) through the same practice or an established referral network is important. Cultural and linguistic match matters in long-term mental health care.
Medically reviewed by AIHealz Medical Editorial Board · May 13, 2026
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