Depressive Disorder

憂鬱症

Depression is a common issue. A meta-analysis found that the lifetime prevalence of depression is 10.8%. Point prevalence of depression was significantly higher in women (14.4%) [1]. Depressive disorder is characterized by low mood, low energy, poor appetite, poor sleep, low sexual drive, poor concentration, and hopelessness. Severe cases may involve suicidal thoughts and false beliefs of guilt. It is currently estimated that at least 30% of people with depression meet the criteria for treatment-resistant depression. Pharmacotherapies (e.g., antidepressants) are the primary treatment for major depressive disorder. Manual-based psychotherapies provide significant symptom relief when combined with conventional antidepressants [2].

A case of depression

Miss Chan is a secretary. Her boss told her, “Could you type this report for me? I have made a few corrections?” Miss Chan is depressed and thinks she is a failure. She believes that she must correct the report. She is bad at her job, and these negative thoughts make her more depressed.

How common is depression?

Depression is common. According to the World Health Organization (WHO), about 280 million people worldwide have depression, including 5% of the world's adults and 5.7% of adults above age 60.

What are the common causes of depression?

Top 10 stressful events in life

Death of a spouse
Divorce
Marital separation
Prison term
Death of a close friend
Illness or injury
Marital problem
Losing your job
Retirement/Menopause

Illnesses linked with depression

Alcohol misuse
Brain tumour
Chronic fatigue syndrome
Dementia
Diabetes
Head injury
Thyroid disorder
Parkinson’s disease

Source:British Medical Association: Understanding Depression Family Doctor Series 2003.

What will your family doctor/psychiatrist do?

Antidepressant tablets can be a very effective treatment for depression. When antidepressants are taken as prescribed, they often start to improve depression in 2 weeks, though it may take longer for full benefit to be felt. You normally continue taking them for at least six months after depression has vanished. Antidepressants can reduce suicide risk if the antidepressants are at adequate doses.

Antidepressants increase neurotransmitters that are low in depression. Different antidepressants have different mechanisms. If one antidepressant does not work, your family doctor/psychiatrist can change the antidepressant.

Many people think they will become dependent on antidepressants, but this will not happen.

Is there any objective test that can further verify whether my brain function is in the range of healthy people or major depressive disorder?

The answer is Yes. A study involving 105 healthy controls and 105 patients with major depressive disorder found that NIRS signals during a mental task were acquired using a functional near-infrared spectroscopy (fNIRS) system, and changes in oxy-haemoglobin in the frontal and temporal regions were quantified. Patients with major depressive disorder had smaller changes in oxy-haemoglobin in the frontal and temporal cortices than healthy controls. In both regions of interest, oxy-haemoglobin was not associated with any of the clinical variables studied. 75.2% and 76.5% of patients with major depressive disorder were correctly classified using frontal and temporal region oxy-haemoglobin, respectively. Haemodynamic response measured by fNIRS during an English letter fluency task is a promising biomarker for major depressive disorder [3].

Source: Academic papers in which Dr Roger Ho is one of the co-authors.

[1] Lim GY, Tam WW, Lu Y, Ho CS, Zhang MW, Ho RC. Prevalence of Depression in the Community from 30 Countries between 1994 and 2014. Sci Rep. 2018 Feb 12;8(1):2861. doi: 10.1038/s41598-018-21243-x. Erratum in: Sci Rep. 2022 Sep 1;12(1):14856. doi: 10.1038/s41598-022-19021-x. PMID: 29434331; PMCID: PMC5809481.

[2] McIntyre RS, Alsuwaidan M, Baune BT, Berk M, Demyttenaere K, Goldberg JF, Gorwood P, Ho R, Kasper S, Kennedy SH, Ly-Uson J, Mansur RB, McAllister-Williams RH, Murrough JW, Nemeroff CB, Nierenberg AA, Rosenblat JD, Sanacora G, Schatzberg AF, Shelton R, Stahl SM, Trivedi MH, Vieta E, Vinberg M, Williams N, Young AH, Maj M. Treatment-resistant depression: definition, prevalence, detection, management, and investigational interventions. World Psychiatry. 2023 Oct;22(3):394-412. doi: 10.1002/wps.21120. PMID: 37713549; PMCID: PMC10503923.

[3] Husain SF, Yu R, Tang TB, Tam WW, Tran B, Quek TT, Hwang SH, Chang CW, Ho CS, Ho RC. Validating a functional near-infrared spectroscopy diagnostic paradigm for Major Depressive Disorder. Sci Rep. 2020 Jun 16;10(1):9740. doi: 10.1038/s41598-020-66784-2. PMID: 32546704; PMCID: PMC7298029.

憂鬱症