Depression
Depression is a mood disorder. According to statistics from the Hospital Authority, more than 300,000 people in Hong Kong suffer from depression. Women are twice as likely as men to suffer from depression, but the symptoms of depression are often more severe in men and should never be ignored.
The two core symptoms of depression are:
1. Persistent low mood
2. Loss of interest or pleasure in activities
Other common symptoms include:
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Significant weight loss or gain—a change of more than 5% of body weight within one month
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Frequent insomnia
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Slowed movements
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Persistent tiredness or lack of energy
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Feelings of worthlessness, or excessive or inappropriate guilt
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Reduced ability to think or concentrate, or frequent indecisiveness
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Recurrent thoughts of suicide or suicidal behaviour
Types and Severity of Depression
Depending on the symptoms and their impact on daily life, depression may be classified as mild, moderate or severe. If a person experiences strong suicidal thoughts, attempts suicide, or develops psychotic symptoms such as auditory hallucinations or persecutory delusions, the depression is considered severe. Prompt intervention is essential, and hospital admission may be required.
Causes of Depression
Depression is not a sign of weakness or an inability to cope with stress. In clinical practice, many people with depression are responsible, motivated and set high standards for themselves. Depression often results from a combination of factors which, at a particular point in a person’s life, contribute to the onset of depressive symptoms.
External Stressors
Psychological Factors
Familial and Genetic Predisposition
The death of a loved one, marital breakdown, parental separation, housing problems, difficulties at work, interpersonal problems, retirement, debt and chronic illness can all cause stress. Such stress may gradually accumulate and, if it becomes overwhelming and is not adequately addressed, may contribute to the onset of depression.
Persistently negative thinking patterns, excessively high expectations of oneself, perfectionistic tendencies and an excessive sense of responsibility can create ongoing psychological stress and may contribute to the development of depression.
People with a parent or sibling who has depression may be 1.5 to 3 times more likely to develop the condition than the general population. However, it is important to emphasise that depression has many possible causes and is not simply an inherited disorder.
Biological Factors
Persistent low mood may affect the function and structure of the brain. Recurrent episodes of depression may be associated with a reduction in the size of the hippocampus, a region involved in emotional regulation and memory formation.
Research has also found that imbalances in neurotransmitters such as serotonin, noradrenaline and dopamine may make a person’s mood more vulnerable to external stress, potentially triggering a depressive episode.
Studies of brain function have identified reduced activity in the left dorsolateral prefrontal cortex (left DLPFC), which is involved in cognitive and thinking processes, in people with depression. This may impair its ability to regulate emotion-related regions such as the anterior cingulate cortex and the amygdala, resulting in excessive activity in these regions.
Impact of Depression
Depression can affect many aspects of a person’s life, including:
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Strained relationships with family and friends, with an increased likelihood of interpersonal conflict
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Reduced performance at work and a greater tendency to make mistakes
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Suicidal thoughts during periods of severe low mood, which may lead to self-harm
Main Treatments for Depression
Treatment for depression depends primarily on the severity of the symptoms and their impact on daily life. Most people experience an improvement in their symptoms following appropriate treatment and may regain their psychological, physical, social and occupational functioning.
The doctor will recommend the most suitable treatment plan for each individual. The main treatment options include medication, psychological therapy and transcranial magnetic stimulation (TMS).
Medication
The main medications used to treat depression are antidepressants. They work partly by regulating neurotransmitters in the brain, such as serotonin, noradrenaline and dopamine. They may also promote the production of brain-derived neurotrophic factor (BDNF), a protein that supports the growth, maintenance and recovery of nerve cells. These effects may help improve mood and relieve emotional distress.
Patients should take prescribed antidepressants regularly and follow their doctor’s instructions. Many patients begin to notice some improvement after approximately two weeks, although the full therapeutic effect may take longer. The doctor will select the most suitable medication based on the patient’s physical health, the severity of the condition and other individual factors. The appropriate dosage also varies from person to person.
The main types of antidepressants include:
Tricyclic Antidepressants (TCAs)
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An older class of antidepressants that may cause more side effects
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Common side effects include drowsiness, dry mouth and constipation
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Certain TCAs may be considered during pregnancy following an individual assessment of the potential benefits and risks
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Some TCAs may also help improve sleep
Selective Serotonin Reuptake Inhibitors (SSRIs)
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A newer class of antidepressants commonly used as a first-line treatment for depression
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Increase the availability of serotonin in the brain, helping to relieve symptoms of depression
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Generally cause fewer side effects than older antidepressants
Serotonin–Noradrenaline Reuptake Inhibitors (SNRIs)
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A newer class of antidepressants
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Act on both the serotonin and noradrenaline systems
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May be considered when a patient has not responded adequately to an SSRI
Intranasal Antidepressants
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Use a novel mechanism of action—the first new approach to antidepressant treatment to be approved in approximately 30 years
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May be suitable for adults with treatment-resistant depression who have previously tried at least two other antidepressants without sufficient improvement
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Act on the glutamate system and may strengthen connections between neurons, as well as help restore dopamine neurotransmission in brain regions involved in reward processing and learning
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May produce a more rapid antidepressant effect and may also be considered, under close medical supervision, for patients with depression who are at acute risk of suicide
Cognitive behavioural therapy (CBT) has been shown to be effective in treating depression. Through individual therapy sessions, a psychologist helps the patient identify and modify negative patterns of thinking and behaviour, thereby improving their emotional well-being.
Transcranial magnetic stimulation (TMS) is a non-invasive treatment that offers an alternative approach for people with depression. It may be suitable for many patients, particularly those who cannot tolerate the side effects of medication or whose symptoms have not responded adequately to several antidepressants.
TMS uses focused magnetic pulses to induce small electrical currents in targeted areas of the brain. These pulses are delivered at specific frequencies to regulate activity within neural circuits associated with cognitive and emotional functions. Stimulation of the left dorsolateral prefrontal cortex (left DLPFC) may help reduce excessive activity in the anterior cingulate cortex (ACC), an area with which it has negatively correlated functional connectivity, thereby helping to alleviate symptoms of depression and anxiety.
TMS has received clearance from the US Food and Drug Administration (FDA) for specified clinical uses. It is generally well tolerated, and serious side effects are uncommon. Treatment is carried out while the patient is awake and does not require anaesthesia.
A full course usually consists of approximately 20 to 30 sessions, with three to five sessions per week. Each session lasts approximately 30 minutes to one hour.