Depression is a common mental health issue affecting millions around the world. It's like being in a cloud of persistent sadness and losing interest in activities you once enjoyed . This isn't just about having a bad day; depression significantly impacts daily life.
Types of Depression
According to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), depression can take several forms [1-3].
- Major Depressive Disorder: This is when feelings of sadness and loss of interest last for at least two weeks.
- Persistent Depressive Disorder (Dysthymia): This type lasts longer, but may not feel as intense.
- Premenstrual Dysphoric Disorder: This type of depression is connected with a woman's menstrual cycle.
- Depressive Disorder Due to Medical Conditions: This type is directly related to a physical health problem.
Prevalence of Depression
Depression is a global issue, affecting people of all ages, including children and adults. One in six individuals between the ages of 10 and 19 worldwide experiences a mental health condition, with depression being a common disorder. In 2021, about 3.4% of the global population had depression . This means around five per cent of the general population experiences depression at some point, which translates to millions worldwide.
Depression in Australia: Facts and Stats
Mental health issues, including depression, are a major concern in Australia, making up 13% of all health conditions in 2018 . They ranked among the top five health problems that year. On average, one out of five Australians aged between 16 and 85 deals with a mental health issue each year [4, 5]. Furthermore, about 44% of Australians within the age range of 16 to 85, which equates to roughly 8.6 million people, have experienced a mental disorder at some point in their lives. In the previous year alone, about 4.2 million Australians experienced a mental health issue. The most prevalent mental health issues in the country include anxiety, mood disorders like depression, and disorders related to substance use [4-6].
Each year, about 1 million Australians are affected by depression and nearly 2 million people face anxiety. For those aged 15 to 25, these two conditions are the second and third most common contributors to health problems, making up 7.6% and 7% of the total health burden for this age group [4, 5].
According to the ABS National Study of Mental Health and Wellbeing, about one-third of Australians aged 16 to 25 (or 31.5%) experience anxiety disorders within a year . About 13.6% of them encounter depressive disorders. Within a year, roughly one in seven people aged 16 to 24, and more than one in ten people aged 25 to 34, undergo a mood disorder, such as depression. The most common mood disorder is a depressive episode, which affects 4.6% of the population. Women are more likely to experience a depressive episode; in the 2020-21 period, 5.3% of women had a depressive episode, compared to 3.8% of men .
Mental health issues not only reduce an individual's quality of life but also cut short the number of healthy years due to illness and premature death. These mental health challenges contribute to 23% of health problems that don't lead to death, becoming the second largest cause of such non-fatal health burdens. Interestingly, nearly all (or 98%) of this burden stems from the everyday challenges of living with these disorders. In 2015, for instance, mental health issues caused Australians to lose a total of 572,775 years of a healthy life, a figure calculated using Disability Adjusted Life Years (DALYs) [4-5]. The Australian healthcare system allocates a hefty $10.4 billion annually to manage mental disorders, ranking them as the fourth most expensive health problem in the country .
Causes and Risk Factors of Depression
Depression often occurs due to adverse life events, such as loss or decline in health. However, depression can also arise without an obvious trigger. Factors contributing to depression can be genetic, environmental, or psychological. Stress, trauma, or a family history of depression can make an individual more susceptible [1-3].
Signs and Symptoms of Depression
If you're suffering from depression, you might experience [1-3]:
- Constant Sadness: Feeling down most of the time.
- Loss of Interest: No longer enjoying activities you once loved.
- Changes in Appetite or Weight: Eating too much or too little.
- Sleep Issues: Difficulty sleeping or sleeping too much.
- Physical Changes: Experiencing changes in physical activity or movement.
- Lack of Energy: Constantly feeling tired.
- Feelings of Worthlessness: Feeling guilty or worthless.
- Difficulty Concentrating: Having trouble with decision-making or attention.
- Suicidal Thoughts: Thinking about self-harm or suicide.
Impact of Depression
Depression can have far-reaching consequences [1-3]. It is linked with decreased educational attainment, especially among teenagers, and can lead to social deprivation and substance abuse. Depression is also a significant risk factor for suicide, impacting not only the individual suffering from depression but also their caregivers, family, friends, and society at large. Depression, therefore, presents a significant burden on individuals, communities, and public health as a whole.
Medications for Depression
There are special medications designed to help manage depression. These medications focus on balancing certain chemicals in the brain that affect our mood. The first of these, introduced in the late 1950s, were called monoamine oxidase inhibitors (MAOIs) and tricyclic antidepressants (TCAs). Today, there are around 35 different kinds of antidepressants used worldwide [1, 2, 7].
One common type of antidepressant is called selective serotonin reuptake inhibitors (SSRIs). They work by increasing the amount of a mood-related chemical called serotonin in the brain. There are also serotonin-norepinephrine reuptake inhibitors (SNRIs) that work similarly, but they affect two chemicals, serotonin and norepinephrine. Tricyclic and tetracyclic antidepressants (TCAs and TeCAs) affect both serotonin and norepinephrine as well. Monoamine oxidase inhibitors work by stopping the action of a certain enzyme that breaks down these mood-related chemicals [1,2, 7].
These antidepressants can help improve mood by changing the levels of these chemicals and improving the way brain cells communicate. It's important to remember that everyone is unique, and these medications may work differently for different people. Sometimes, changes in the amount of medication or the type of medication may be needed .
Therapies for Depression
Alongside medication, certain types of therapy are effective in treating depression.
Cognitive-behavioural therapy (CBT) is a therapy that helps individuals recognize and change negative thinking and behaviour patterns linked to depression. This approach focuses on reshaping thoughts and adopting behaviours that can enhance mood and overall functioning. It can be helpful for people of all ages and is useful in preventing future bouts of depression .
Mindfulness-based cognitive therapy (MBCT) is a type of CBT designed to prevent relapse in people who frequently experience depression. It includes mindfulness practices to help manage repetitive thought patterns .
Interpersonal therapy (IPT) is another type of therapy with a set timeframe that concentrates on relationships and current issues causing stress. It helps in managing issues like grief, interpersonal conflicts, changes in life roles, and developing social skills .
Treatment-resistant depression (TRD) is a specific type of Major Depressive Disorder (MDD). In this type of depression, the person does not respond to standard and initial treatments that are typically used as the first line of therapy . Although different definitions exist for TRD, it's generally understood as a situation where an individual hasn't shown improvement after trying two different antidepressant medications. MDD is a very diverse condition, and about 30% of people diagnosed with MDD don't respond to conventional treatment methods, resulting in what is known as TRD.
Several therapeutic options are available for TRD :
- Brain Stimulation, such as TMS (Transcranial Magnetic Stimulation): This advanced treatment involves the application of brief magnetic pulses to the brain, leading to cortical stimulation. It's a non-invasive technique that does not require surgery or seizure induction. Instead, TMS uses an electromagnetic coil placed on the scalp to generate a powerful magnetic field that stimulates cortical neurons. Patients being treated with TMS undergo five daily treatment sessions over three to six weeks, resulting in a total of 20 to 30 sessions.
- Psychotherapy: Techniques like cognitive-behavioural therapy, interpersonal therapy, and mindfulness-based cognitive therapy can reduce symptoms and improve long-term outcomes.
- Lithium Augmentation: Boosting the antidepressant treatment with lithium, particularly when used with certain other antidepressants.
- T3 Augmentation: Adding T3, a thyroid hormone, to the antidepressant treatment can improve symptoms, especially when used with certain antidepressants.
- Second-Generation Antipsychotics Augmentation: Certain antipsychotic medications have shown positive results when used with other specific antidepressants.
- Optimizing Antidepressant Pharmacotherapy: Adjusting dosages, combining antidepressants, or switching to a different type can help improve outcomes.
TMS (Transcranial Magnetic Stimulation) Efficacy
Transcranial Magnetic Stimulation (TMS) is a non-invasive treatment for patients with Treatment-Resistant Depression (TRD). It uses an electromagnetic coil to repeatedly send targeted pulses to certain brain cells, altering their activity without causing a seizure. This is a non-surgical treatment that's done on the outside of the scalp, generally targeting a specific part of the brain known as the dorsolateral prefrontal cortex using a handheld magnetic coil [10, 11].
rTMS has been tested in many scientific studies over the last 20 years, involving thousands of patients. These tests have shown that they can be effective in treating depression. Because of these positive results, health authorities in countries like Canada, the US, Europe, Australia, and Israel have approved rTMS for treating depression that doesn't respond to other treatments [10, 11].
This method was first tried out on healthy people, who showed some improvements in their mood after the treatment. Later on, when researchers used rTMS on people with major depression, they found that it significantly helped 4 out of 6 patients who had not responded to other treatments.
There are several ways to use rTMS, each with its success rate. One approach, called Conventional High-Frequency Left DLPFC rTMS, was shown in a 2010 study to help about 14.1% of patients in a controlled study and approximately 30% in a later follow-up trial. Another study in 2014 found a response rate of 29.3% in 1,371 patients with treatment-resistant depression, nearly twice the rate seen with certain antidepressant medications [10, 11].
Another type of rTMS called Theta-Burst Stimulation (TBS) tries to closely target and promote changes in brain activity [10, 11]. This method uses bursts of three pulses delivered five times per second. A large-scale trial found that TBS was just as effective as regular rTMS, leading to the FDA giving it the green light as a new treatment for depression that doesn't respond to other treatments.
Recently, researchers have been looking at accelerated rTMS, which involves giving multiple treatment sessions per day . This approach is being considered for patients in critical situations, such as those with severe suicidal thoughts. Early research suggests that this method may lead to higher levels of brain activity and plasticity with multiple rTMS sessions in one day. In some studies, this method led to recovery rates of up to 56%. However, the accelerated treatment might cause more discomfort and a slightly higher dropout rate.
In a comprehensive study from 2017, researchers examined data from 81 rTMS studies, comparing eight different rTMS methods with placebo treatments. The researchers found that high frequency, low frequency, bilateral rTMS, and TBS all helped patients more than the placebo treatment. Furthermore, all rTMS treatments were well-tolerated by the patients, much like the placebo treatments [10, 11].
To sum up, rTMS has been established as an effective and well-tolerated option for treating depression that doesn't respond to other treatments. But we still need more detailed research to determine the best way to use rTMS and to rank the different treatment methods.
Availability of TMS in Australia
Transcranial Magnetic Stimulation, often known as TMS, is a technique used to treat depression. It's been approved for use in several countries, including Australia, since 2007. TMS works by using an electromagnetic coil to send targeted pulses to specific areas of the brain that deal with mood control. This method is safe and has few side effects.
In Australia, to start TMS treatment, you need a referral from your General Practitioner (GP). After getting a referral, you'll be assessed by a psychiatrist who specializes in TMS. If you are deemed eligible, your TMS treatment will then be given by a specially trained operator .
Exciting news for Australians is that Medicare, the national health insurance scheme, can cover TMS treatment costs if you meet certain criteria . To be eligible, you need to be at least 18 years old and diagnosed with a major depressive episode. Additionally, you must have tried at least two different types of antidepressant medications without satisfactory improvement, unless there's a specific reason why you shouldn't take these medications. Other requirements include your commitment to the treatment and adjustments to the highest tolerated dose. You must also have tried psychological therapy if it's suitable for you .
The Medicare Benefits Schedule (MBS) includes four specific items related to TMS treatment for depression .
- Prescription and initial planning for TMS treatment.
- Delivery of an initial course of up to 35 TMS treatment sessions.
- Prescription and planning for a repeated course of TMS treatment.
- Delivery of a repeated course of up to 15 TMS treatment sessions.
To access these services, you need a referral from a GP or a psychiatrist. The treatment can be provided in various settings, including outpatient or consultation rooms, or even in a hospital for some cases. In all situations, Medicare rebates are applicable to eligible patients .
The person administering TMS should be a psychiatrist trained in this method or a healthcare professional supervised by the psychiatrist. This trained psychiatrist is responsible for planning and monitoring your treatment outcomes and should be available to advise on the treatment. Providers must also comply with ongoing training requirements.
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