Depression: Patient Information Leaflet

What is Major Depressive Disorder (MDD)?

Major Depressive Disorder is one of the most common and disabling psychiatric conditions worldwide. It is characterized by episodes of persistent low mood and/or a marked loss of interest or pleasure in activities (anhedonia), accompanied by a range of physical symptoms — changes in sleep, appetite, and energy — and cognitive symptoms such as poor concentration, feelings of worthlessness, and, in more severe cases, thoughts of death or suicide. Episodes may occur once or recur throughout life, and severity ranges from mild to severe, occasionally with psychotic features.

Common symptoms of Major Depressive Disorder (MDD)

• Depressed mood most of the day, nearly every day
• Markedly diminished interest or pleasure in almost all activities (anhedonia)
• Significant weight loss or gain, or change in appetite
• Insomnia or hypersomnia (sleeping excessively)
• Psychomotor agitation or retardation (restlessness or noticeably slowed movement/speech)
• Fatigue or loss of energy
• Feelings of worthlessness or excessive, inappropriate guilt
• Diminished ability to think, concentrate, or make decisions

What causes Major Depressive Disorder (MDD)?

MDD arises from a combination of genetic vulnerability (heritability of around 40%), dysregulation of neurotransmitter systems (serotonin, noradrenaline, and dopamine), and disruption of the hypothalamic-pituitary-adrenal (HPA) axis, which governs the body's stress-hormone response. Chronic stress, significant loss, trauma, and adverse childhood experiences increase vulnerability, and depression frequently co-occurs with or follows chronic medical illness.

Treatment options for Major Depressive Disorder (MDD)

Mild depression often responds well to psychotherapy alone. Moderate-to-severe depression generally requires a combination of psychotherapy (such as CBT or Interpersonal Therapy) and antidepressant medication. Severe depression with psychotic features, high suicide risk, or an inability to care for oneself may require hospitalization, and treatment-resistant or severe cases may be considered for electroconvulsive therapy (ECT), which remains one of the most effective treatments for severe depression.

Self-help tips for Major Depressive Disorder (MDD)

• Engage in regular physical exercise, which has evidence comparable to medication for mild-to-moderate depression
• Maintain a consistent sleep schedule and address sleep disturbance directly
• Stay socially engaged even when motivation is low, rather than withdrawing
• Establish a structured daily routine, especially when energy and motivation are reduced
• Limit alcohol, which is a depressant and can worsen symptoms
• Prioritize sunlight exposure and time outdoors where possible

What is the outlook (prognosis) for Major Depressive Disorder (MDD)?

MDD is highly treatable, with most people experiencing substantial improvement with appropriate treatment. However, depression has a significant risk of recurrence — over 50% after a first episode, and higher after multiple episodes — which is why maintenance treatment is often recommended for people with recurrent depression, even after symptoms resolve.