Depression - Epidemiology and Biological Basis Flashcards
According to the International Classification of Diseases, what are the core features of depression?
Low mood Loss of interest and enjoyment (anhedonia) Reduced energy (leading to increased fatiguability and diminished activity)
Define ‘mild’ depression.
2 core symptoms, 2 others None to an “intense degree” Distressed and “some difficulty” continuing with ordinary work and social activities
Define ‘moderate’ depression.
2 core symptoms, 3 or 4 others “Considerable difficulty continuing with ordinary work and social activities
Define ‘severe’ depression.
3 core symptoms, 4 others with some of “severe” intensity Unlikely able to continue social, work or domestic activities Includes all psychotic depression
Suicide is the second leading cause of death in which age group?
15-29, according to the WHO
According to the WHO, depression is the leading cause of disability world wide. True/false?
True
What is the ratio of males to females affected by depression?
1:2 - prevalence is double in females
What is the estimated prevalence of depression in the general population and in people with chronic illness? (US)
7% in general population 25% in patients with chronic illness
Name 4 epidemiological differences between bipolar disorder and unipolar depressive disorders.
- Bipolar disorder has much lower lifetime prevalence - estimated to be 0.3-1.5% 2. Bipolar disorder has the same 6-12 month prevalence as lifetime prevalence, indicating it is highly chronic. Unipolar disorders have a considerably lower 6-12 month prevalence than lifetime. 3. Mean age of onset is 17-21 in bipolar disorder and 27 in unipolar disorders. 4. Bipolar disorder is equally prevalent in males and females, whereas unipolar disorders affect double as many females.
Polymorphisms in which hormone receptor appear to reduce risk of depression?
Corticotrophin releasing hormone (CRH)
Polymorphisms in which chromosomes are associated with several mental health disorders, including depression?
3 and 10
What is the evidence for and against the involvement of genetics in depression?
There are higher concordance rates between 1st degree relatives and twins than we would expect to arise due to chance alone. However, these concordance rates are well below 100%, indicating there are other factors involved. Twins share similar psycho-social environments, which could account for the high concordance rate. Conclusion: there is clearly a genetic basis for depression, but other factors also play a significant role.
Name the 5 main neurotransmitters implicated in depression.
Serotonin, dopamine, noradrenaline, GABA, glutamate
The levels of what are increased by antidepressants and possibly ECT, and decreased by stress?
BDNF - brain derived neurotrophic factor
Explain the 5 main pieces of evidence for the monoamine (MA) hypothesis of depression.
- Reduced plasma concentrations of 5-HT precursors in patients with depression. 2. Reduced 5-HT in post-mortem brains of suicide victims and depressed patients. 3. Depleting tryptophan (serotonin precursor) leads to relapse of depression in patients. 4. Drugs that deplete NA e.g. desipramine induce depressive symptoms in recovered patients. 5. Decreased dopamine metabolites in CSF linked to depression.
