Introduction
Mood disorders are mental health conditions where persistent disturbance of mood—depression, mania, or both—causes significant distress or impairment. Major categories include major depressive disorder, bipolar disorder, persistent depressive disorder (dysthymia), and related specifiers.
Depression involves prolonged low mood, loss of interest, sleep and appetite changes, fatigue, guilt, poor concentration, and sometimes suicidal thoughts. Bipolar disorder adds episodes of mania or hypomania—elevated mood, increased energy, reduced sleep need, impulsivity, and sometimes psychosis.
Effective treatments include psychotherapy, antidepressants, mood stabilisers, antipsychotics, and lifestyle interventions. Early recognition and adherence improve outcomes and reduce suicide risk.
This page provides an overview of common mood disorders, symptoms, causes, diagnosis, treatment, crisis warning signs, and when urgent mental health care is needed.
Overview
Mood disorders are among the leading global causes of disability. They often begin in adolescence or young adulthood but can occur at any age. Comorbid anxiety, substance use, and medical illness are common.
Diagnosis uses structured clinical criteria (DSM/ICD). Medical causes—hypothyroidism, anaemia, medications—must be excluded when indicated.
Prognosis improves with combined biological and psychosocial treatment and social support.
- Include depression, bipolar disorder, dysthymia, cyclothymia
- Depression: low mood, anhedonia, neurovegetative symptoms ≥2 weeks
- Bipolar: depressive plus manic/hypomanic episodes
- Strong genetic and environmental contributions
- Treatment: therapy, medications, lifestyle, crisis planning
- Suicide risk assessment essential in all mood disorders
- Medical and substance-induced mimics must be excluded
- Chronic but manageable with ongoing care
What happens in the body
Depression involves dysregulation of monoamine neurotransmitters, stress-axis hyperactivity, inflammatory signals, and altered brain network function in prefrontal and limbic regions. Bipolar disorder adds unstable circadian and dopaminergic drive during mania.
Psychosocial stress, trauma, and sleep disruption trigger episodes in genetically vulnerable individuals.
- Genetic heritability moderate for depression and higher for bipolar
- HPA axis and inflammation implicated in some depression
- Mania linked to dopaminergic excess and circadian rhythm disruption
- Kindling model: recurrent episodes may lower trigger threshold
- Neuroplasticity changes with chronic untreated illness
Signs and symptoms
Symptoms differ between depressive and manic poles:
- Depression: sad mood, anhedonia, insomnia or hypersomnia, appetite change, fatigue, worthlessness, poor focus, suicidal ideation
- Mania/hypomania: elevated or irritable mood, grandiosity, decreased sleep need, talkativeness, racing thoughts, risky behaviour, psychosis in severe mania
- Mixed features: depression with agitation and manic energy
- Seasonal pattern in some depressions
- Peripartum mood episodes in pregnancy/postpartum
- Physical aches without clear medical cause in depression
Causes and risk factors
Multifactorial biopsychosocial model:
- Family history of depression or bipolar disorder
- Childhood trauma and chronic stress
- Medical illness: hypothyroidism, Parkinson disease, chronic pain
- Medications: steroids, interferon, some cardiovascular drugs
- Substance use: alcohol, stimulants
- Major life events and social isolation
- Not weakness of character—medical brain–mind conditions
Diagnosis and evaluation
Clinical interview and criteria-based diagnosis:
- Structured history of mood episodes, duration, functional impact
- Screen for mania before starting antidepressants in bipolar-spectrum patients
- PHQ-9, MDQ, or other tools as adjuncts not substitutes
- Labs: TSH, B12, metabolic panel when medically indicated
- Exclude substance-induced and grief (with duration/context rules)
- Risk assessment for suicide and self-harm
Treatment and management
Individualised combination therapy:
- Psychotherapy: CBT, interpersonal therapy, behavioural activation, DBT as appropriate
- Antidepressants (SSRIs, SNRIs, etc.) for depression with monitoring for activation in bipolar
- Mood stabilisers: lithium, valproate, lamotrigine in bipolar disorder
- Antipsychotics for mania or treatment-resistant depression augmentation
- Electroconvulsive therapy or TMS for severe or refractory depression
- Sleep regularisation and exercise as adjuncts
- Substance use treatment integrated when comorbid
- Crisis plan and emergency contacts for suicidal ideation
Prevention, self-care, and lifestyle
Not every condition is fully preventable, but the steps below may lower risk or recurrence:
- Treat subsyndromal symptoms early
- Maintain sleep schedule and reduce alcohol
- Stress management and social connection
- Adherence to maintenance mood stabilisers in bipolar disorder
- Postpartum monitoring and support
Possible complications
Delay, missed care, or unsafe self-medication can raise the chance of complications in some cases:
- Suicide and self-harm
- Disability, job loss, relationship breakdown
- Substance misuse as self-medication
- Medical comorbidity from poor self-care in depression
- Cardiometabolic effects of some psychotropic medicines
- Psychosis during severe mania or melancholic depression
When to see a doctor or seek emergency care
Seek prompt medical advice or emergency care if any of the following apply—it is safer not to wait and see:
- Persistent low mood or loss of interest more than two weeks
- Suicidal thoughts, plans, or self-harm urges—crisis line or emergency
- Suspected mania: decreased sleep with risky behaviour
- Postpartum mood symptoms beyond brief blues
- Depression not improving on initial treatment
Living with the condition
Mood disorders are chronic-recurrent for many—maintenance therapy and early warning sign lists help. Sleep protection is critical in bipolar disorder. Peer support and psychoeducation reduce stigma and isolation.
Frequently asked questions
Are mood disorders curable?
Many achieve long remissions; bipolar often needs lifelong management. Depression may be single-episode or recurrent.
Do antidepressants cause bipolar?
They can trigger mania in undiagnosed bipolar—screen for manic history before prescribing.
Is hospitalisation needed?
Severe suicide risk, psychosis, or inability to care for self may require inpatient care.
Important caution
This article is general mental health education, not personal psychiatric treatment.
If you are in immediate danger of self-harm, contact emergency services or a crisis helpline now.
Medication changes for mood disorders require clinician supervision—do not stop abruptly.