According to the World Health Organization (WHO), depression is the most common illness worldwide and the leading cause of disability. They estimate that 350 million people are affected by depression, globally.
- Depression seems to be more common among women than men.
- Symptoms include lack of joy and reduced interest in things that used to bring a person happiness.
- Life events, such as bereavement, produce mood changes that can usually be distinguished from the features of depression.
- The causes of depression are not fully understood but are likely to be a complex combination of genetic, biological, environmental, and psychosocial factors.
Depression is a mood disorder characterized by persistently low mood and a feeling of sadness and loss of interest. It is a persistent problem, not a passing one, lasting on average 6 to 8 months.
Diagnosis of depression starts with a consultation with a doctor or mental health specialist. It is important to seek the help of a health professional to rule out different causes of depression, ensure an accurate differential diagnosis, and secure safe and effective treatment.
As for most visits to the doctor, there may be a physical examination to check for physical causes and coexisting conditions. Questions will also be asked – “taking a history” – to establish the symptoms, their time course, and so on.
Some questionnaires help doctors to assess the severity of depression. The Hamilton depression rating scale, for example, has 21 questions, with resulting scores describing the severity of the condition. The Hamilton scale is one of the most widely used assessment instruments in the world for clinicians rating depression.
What does not class as depression?
Depression is different from the fluctuations in mood that people experience as a part of normal life. Temporary emotional responses to the challenges of everyday life do not constitute depression.
Likewise, even the feeling of grief resulting from the death of someone close is not itself depression if it does not persist. Depression can, however, be related to bereavement – when depression follows a loss, psychologists call it a “complicated bereavement.”
Signs and symptoms
Symptoms of depression can include:
- depressed mood
- reduced interest or pleasure in activities previously enjoyed, loss of sexual desire
- unintentional weight loss (without dieting) or low appetite
- insomnia (difficulty sleeping) or hypersomnia (excessive sleeping)
- psychomotor agitation, for example, restlessness, pacing up and down
- delayed psychomotor skills, for example, slowed movement and speech
- fatigue or loss of energy
- feelings of worthlessness or guilt
- impaired ability to think, concentrate, or make decisions
- recurrent thoughts of death or suicide, or attempt at suicide
The causes of depression are not fully understood and may not be down to a single source. Depression is likely to be due to a complex combination of factors that include:
- biological – changes in neurotransmitter levels
- psychological and social (psychosocial)
Some people are at higher risk of depression than others; risk factors include:
- Life events: These include bereavement, divorce, work issues, relationships with friends and family, financial problems, medical concerns, or acute stress.
- Personality: Those with less successful coping strategies, or previous life trauma are more suceptible.
- Genetic factors: Having a first-degree relatives with depression increases the risk.
- Childhood trauma.
- Some prescription drugs: These include corticosteroids, some beta-blockers, interferon, and other prescription drugs.
- Abuse of recreational drugs: Abuse of alcohol, amphetamines, and other drugs are strongly linked to depression.
- A past head injury.
- Having had one episode of major depression: This increases the risk of a subsequent one.
- Chronic pain syndromes: These and other chronic conditions, such as diabetes, chronic obstructive pulmonary disease, and cardiovascular disease make depression more likely.