Introduction to the complex world of mood Flashcards
What are affective disorders?
Neuropsychiatric conditions broadly divided into 2 conditions:
- Depressed mood (MDD, clinical, unipolar, or major depression)
- Bipolar disorder
= Mood disorders
- conditions characterised by a disturbance in one’s mood
What do the DSM and ICD offer?
- Common language, standard criteria
- help mh professionals determine/communicate patient’s diagnosis - Diagnostic criteria for research
- Resource for health insurance, pharmaceutical companies, and legal system
What are the comorbidities associated to affective disorders?
- Anxiety disorders
- Substance use disorders
- Impulse control disorders
What is the association between mood disorders and dementia?
Increased risk of dementia
- over 60,000 individuals, depression associate with 2-fold increased risk of developing dementia in older age
How does the identification of correlates and causes differ in mood disorders?
Correlates are more easily identifiable than causes in mood disorders
What is aetiology of an affective disorder?
> Nurture: environment/experience
> Nature: genes
What can improve our understanding of affective disorders?
> Engagement and communication with patients and their families
> Evaluation of underlying biological factors
How can you evaluate the underlying biological factors of affective disorders?
- Examining patients’ blood, saliva, hair, nails, urine, faecal matter
- Imaging techniques (patients vs. controls)
- Post-mortem sampling
- iPS cells
- Use of genome association and animal models
What is the benefit of using animal models for understanding mood disorders?
> Provide behavioural readouts
> Enhance understanding of biological underpinning through brain-behaviour associations
> Help identify new underlying pathways, drug targets, test protective interventions
What are the four types of environmental manipulations (procedures) we can operate in animal models?
> Social isolation
> Unpredictable chronic mild stress
> Social defeat (introduction of agressive animal)
> Physical manipulations
- restraint stress
- maternal deprivation
- sleep deprivation
What are the three types of internal alterations we can operate in animal models?
> Permanent
- olfactory bulbectomy (removal of olfactory bulb)
- adrenalectomy (removal of adrenal glands)
> Transient
- manipulation of immune/stress systems
- disruptions induced by changing dietary composition
> Genetic modifications
Which genetic modifications can be made in animal models?
> Transgenic and knock-out animals with genetically altered systems
> Selection of extreme types from an animal population
> Use of inbred strains
What is the purpose of pharmacogenetics?
Identify genetic variants that control efficacy and possible adverse reactions to drugs
What is the genetic contribution to unipolar depression (Craddock and Forty, 2006)
Between 33-42%
What is the genetic contribution to bipolar disorder (Craddock and Forty, 2006)?
Between 80-90%
What did the mega-analysis of genome-wide association studies for major depressive disorders (Ripke et al., 2013) show?
> No single nucleotide polymorphisms (SNPs) reaching genome-wide significance
> Lack of result might be due to underlying heterogeneity of MDD cases part of the study
What is the limit of most studies that try to identify the genetic contribution to depression?
- Insufficient power
- Need of large sample size and/or decrease in heterogeneity of selected cases
Which neuroimaging techniques indirectly measure neuronal activity?
- PET
- SPECT
- fMRI
Which neuroimaging techniques directly measure electrical activity?
- MEG
- EEG
How do PET and SPECT scans indirectly measure neuronal activity?
Look at distribution and density of neurotransmitter receptors in certain areas
How does grey matter vary in depressive disorders (Redlich et al., 2014)?
Individuals with bipolar depression (BD) had decreased grey matter in sagittal and coronal slices of hippocampus and amygdala
vs. those with unipolar depression UD)
What is the effect of electroconvulsive therapy (ECT) on the cortical structures of patients with major depression (Joshi et al., 2016)?
- Patients with refractory depression showed smaller hippocampal volumes at baseline compared to controls
- Increase in hippocampal and amygdala volumes after ECT treatment in relation to improvement in symptoms
What is the National Institute for Health and Care Excellence (NICE)?
Public organisation which is part of Department of Health in UK
- helps clinicians to choose the best therapies for their clients based on research, therapeutic outcomes, and health economics
What is the leading cause of disability worldwide according to the World Health Organization (WHO, 2018)?
Depression
- high rate of relapse despite wide range of psychological/pharmacological treatments available
