Depression is one of the most common causes of suffering and disability. It is not a sign of weakness, nor something that can be solved by willpower alone.
What it is
A depressive episode is diagnosed when depressed mood or loss of interest and pleasure in usual activities is present most of the day, nearly every day, for at least two weeks, together with other symptoms and with an impact on personal, family or working life.
It results from the interaction of biological, psychological and social factors. Physical illnesses, some medicines and alcohol use can cause or worsen it. The relationship with cardiovascular disease runs both ways: depression increases cardiovascular risk and is more common in people with heart disease.
Signs and symptoms
- persistent sadness, emptiness or irritability;
- loss of interest or pleasure in almost all activities;
- disproportionate tiredness and lack of energy;
- changes in sleep (insomnia or sleeping too much) and in appetite or weight;
- difficulty concentrating and making decisions;
- slowing down or, conversely, agitation;
- feelings of excessive guilt or worthlessness;
- recurrent thoughts of death or suicide.
When to seek an assessment
When symptoms last more than two weeks and interfere with work, relationships or self-care; when they return after a period of improvement; or when a current treatment is not working. Suicidal thoughts require urgent assessment.
What the assessment involves
The psychiatric assessment characterises the current and previous episodes, their severity and risk, and looks for factors that would change treatment. One of the most important points is to find out whether there have been periods of euphoria, excessive energy or a reduced need for sleep, because bipolar disorder often begins with depressive episodes and is treated differently.
Depending on the case, blood tests may be requested (for example thyroid function, vitamin B12, full blood count) to rule out medical causes, and the medication the person already takes is reviewed.
Treatment
Treatment depends on severity, history and the person's preferences:
- Mild depression: psychoeducation, behavioural activation, structured physical activity and psychotherapy (for example cognitive behavioural therapy) are first-line options.
- Moderate to severe depression: combining an antidepressant with psychotherapy is generally more effective than either alone.
Antidepressants usually take a few weeks to work. After improvement, continuing them for at least six months is recommended to reduce the risk of relapse; stopping should be gradual and supervised. Regularising sleep and treating associated physical illnesses are part of the plan.
Treatment-resistant depression
Depression is considered treatment-resistant when it does not respond to at least two antidepressant treatments of adequate dose and duration. Before changing strategy, the diagnosis, adherence and other factors (physical illness, alcohol use, an associated personality or anxiety disorder) are reviewed.
Options include optimising or switching the antidepressant, adding another medicine, intensifying psychotherapy, an intranasally administered medicine approved for treatment-resistant depression and given in a clinical setting, and electroconvulsive therapy. Learn more about psychedelic-assisted therapy.
Frequently asked questions
What is the difference between sadness and depression?
Sadness is a normal reaction to loss and hardship and tends to ease with time. In depression, mood and interest are persistently altered, with other symptoms (sleep, energy, concentration, guilt) and an impact on functioning.
Are antidepressants addictive?
They do not cause dependence in the sense of addiction, and the dose does not need to be increased to maintain the effect. Stopping abruptly can cause discontinuation symptoms, which is why tapering should be gradual and supervised by the doctor.
How long does treatment last?
It varies. After remission of a first episode, medication is usually continued for at least six months. In people who have had several episodes, longer maintenance treatment may be justified.
References
- National Institute for Health and Care Excellence. Depression in adults: treatment and management (NG222). 2022.
- American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 5th ed., text revision (DSM-5-TR). 2022.
- World Health Organization. Depressive disorder (depression), fact sheet. 2023.
This page is for information only and does not replace an individual medical assessment. Clinical review: Pedro Zuzarte, psychiatrist · Published and reviewed: .