DEFINITION
FACTS
PRINCIPAL TYPES OF DEPRESSION
CAUSES
SIGNS AND SYMPTOMS
rTMS AND DEPRESSION
SEARCH JOURNAL ARTICLES

DEFINITION

• Depression is a mental illness that manifests with low mood, low self-worth, sadness, lack of interest in everyday activities, feelings of guilt or worry, disturbed sleep and appetite, as well as poor concentration. Depression can be triggered by a tragic event or can occur unprompted. It is highly correlated with decreased levels of activity in the prefrontal cortex of the brain, particularly on the left side.

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FACTS

• Depression affects about 121 million people worldwide
• It is the second largest killer after heart disease and is shown to be a contributory factor to fatal coronary disease
• About 20% of men and 30% of women suffer from depression during their lifetimes
• An astounding 23% of children worldwide suffer from depression
• Less than 30% of those with depression experience some symptom alleviation from antidepressants
• Depression results in more absenteeism than any other physical disorder and costs employers hundreds of billions a year in lost productivity
• It is the fourth leading contributor to the global burden of disease

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PRINCIPAL TYPES OF DEPRESSION

Major Depression (Clinic Depression, Unipolar Depression): social and/or occupational impairment, sadness, apathy, hyperactivity, feelings of worthlessness, fatigue, poor attention, sleep and appetite difficulties, poor sexual interest or ability, decreased speech, emotion, and movement. Major depression usually strikes people between the ages of 25 and 44, although it can affect any person at any age. For most people, episodes of major depression last from six to nine months.

Dysthymia: longer lasting, yet milder than major depression. About 3% of the population will suffer from dysthymia at some time. Poor school/occupational performance, social withdrawal, shyness, irritability, conflicts with friends and family, physiological abnormalities, sleep disturbances, parents with major depression.

Manic-Depressive (Bipolar Disorder): inflated self-esteem, decreased need for sleep, more talkative or pressured speech, flight of ideas, poor concentration, increased agitation, reckless involvement in pleasurable activities, sadness, apathy, disturbed appetite, fatigue, excessive worry or guilt, and recurrent thoughts of death. About 1% of the population age 18 or older will suffer from manic-depressive disorder at some time.

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CAUSES

There is no one cause of depression. However, there are general factors that may make some people more likely than others to experience this mental illness. These may include biological or genetic, psychological, or social factors:

• Biological/Genetic:  some people who are depressed have an imbalance or a change in the level of a biochemical in their brain. Others may be at a greater risk of having depression if close blood relatives suffered from depression.

• Social:  for many people, depression is triggered by social factors, such as stressful life events, or alcohol and drug abuse.

• Psychological:  having a negative or pessimistic view of life may also contribute to depression.

• Depression is still not fully understood so there may be no obvious trigger for some people. For example, a physical illness or taking certain kinds of medication may cause symptoms of depression.

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SIGNS AND SYMPTOMS

The signs and symptoms of depression fall into three broad categories: mood, physical, and cognitive ("thought") symptoms:

Mood symptoms

• Persistent feelings of sadness
• Reduced ability to experience pleasure (i.e. loss of interest)
• Irritability and intolerance

Physical symptoms

• Changes in appetite (i.e. eating more or less than usual)
• Changes in sleep (i.e. sleeping more or less than usual)
• Changes in energy level
• Disturbances of motor function
• Physical aches and pain

Cognitive symptoms

• Thoughts or feelings of hopelessness and helplessness
• Thoughts or feelings of guilt and pessimism
• Disturbances of attention, concentration and memory

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rTMS AND DEPRESSION

• In treating depression, rTMS therapy targets the area just a few inches above the temple and beneath the skull. This area is called the left dorsolateral prefrontal cortex (DLPFC). The DLPFC is readily accessible to the magnetic field and is highly interconnected with limbic structures, which plays a dominant role in mood modulation and major depression. rTMS is used to treat depression by inducing a current in the DLPFC with stimulation by a magnetic field. Several studies have suggested that rTMS regulates beta adreno receptors and increases dopamine and serotonin levels.
• rTMS can alter activity in other remote brain structures that are not directly accessible to the rTMS coil by focal cortical stimulation. Some of these remote brain structures are also believed to be linked to depression. The indirect stimulation occurs via trans-synaptic effects. This means that the accessible areas of the brain, such as the DLPFC described above, are first directly stimulated by the magnetic field. This direct stimulation will then cause the inaccessible areas of the brain to be stimulated which results in an indirect stimulation.
• Brain imaging techniques demonstrate that individuals suffering from depression often portray insufficient levels of glucose metabolism, lower blood flow in the DLPFC and increased activity in the Limbic system. rTMS creates a magnetic current in the DLPFC to regulate the flow of interactions between neurons that will appropriately increase or decrease the desired regions to relieve the depression.
• The human brain is naturally an electrical organ that functions through transmitting electrical signals from one nerve cell to another. rTMS plays on this process by simply increasing the number and frequency of transmissions.
• High frequency rTMS is administered to the left DLPFC.
• The stimulations are short but intense, lasting less than a millisecond. The penetration itself holds little energy.
• The initial course of rTMS therapy for Depression involves 20 to 30 treatment sessions, over a period of 2 to 3 consecutive weeks.

   Please contact MindCare Centres staff members directly to obtain further details

EXCERPTS FROM PEER-REVIEWED MEDICAL JOURNAL ARTICLES ON RTMS:

• “Over the 3 weeks, the active rTMS treatment was superior to sham TMS… which indicates not only a statistically but also a clinically significant effect. The patients had typically been through two failed antidepressant treatment attempts with non-tricyclics before inclusion in the study.” (Bretlau et al., 2008)
• “These findings show that high-frequency rTMS over the left DLPFC is superior to sham in the treatment of depression. The effect size is robust and comparable to at least a subset of commercially available antidepressant drug agents.” (Schutter, 2008)
• “Repeated rTMS applications have demonstrated a reproducible antidepressant effect in patients with refractory depression who initially showed a clinically significant benefit. The duration of effect varied across patients, but benefits were sustained for a mean of nearly 5 months.” (Demirtas-Tatlidede et al., 2008)
• “All published, sham-controlled rTMS depression trials were reviewed for reported side-effects and outcomes of formal neuropsychological testing…the overall safety profile of rTMS is good, and supports its further development as a clinical treatment.” (Loo et al., 2008)
• “High-frequency rTMS of the left dorsolateral prefrontal cortex is effective in treatment-resistant depression.” (Kito et al., 2008)
• “Active TMS was significantly superior to sham TMS... Active TMS was well tolerated with a low dropout rate for adverse events (4.5%) that were generally mild and limited to transient scalp discomfort or pain.” (O’Reardon et al., 2007)
• "...rTMS in the high-frequency range is effective in patients with drug-resistant major depression." (Rossini et. al, 2005)
• "There was a significantly greater response to active than sham stimulation at 2 weeks and across the full duration of the study. A significant proportion of the study group receiving active treatment met response (11 of 25 [44%]) or remission (nine of 25 [36%]) criteria by study end compared to the sham stimulation group (two of 25 [8%] and none of 25 respectively)." (Fitzgerald et. al, 2006)

• "Double-blind, placebo-controlled trial finds 61% of patients respond to rTMS therapy." (Rossini et. al, 2005):

• "In patients treated with rTMS, cognitive performance remained constant or improved and memory complaints alleviated, whereas in the ECT group memory recall deficits emerged and memory complaints remained." (Schulze-Rauschenbach et. al, 2005):

• "A substantive number of the trials published so far support the efficacy of TMS as a nonpharmacological tool in the treatment of the drug-resistant depressives." (Rossini et. al, 2005)
• Holtzheimer Study of Hamilton Depression Rating Scales shows rTMS with a 22% deduction in scores and sham treatment with a 8% deduction.
• "This study adds to the growing literature supporting an antidepressant effect for rTMS. This study is particularly relevant because it suggests that rTMS and ECT reach similar results in nonpsychotic major depressive disorder." (Grunhaus et. al, 2003)
• "The meta-analysis supports the hypothesis that left prefrontal rTMS is an acute antidepressant treatment with statistically significant effect sizes and measurable clinical improvement." (Kozel, 2002)

Search journal articles on Depression

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