Etiology of mental illness

Aetiology of Mental Disorders

Professor Dr .Elham aljammas 9thof oct 2018

Objectives:

1.To determine the most important factor in the etiology of thedisorder 2.to treat the cause 3.to prevent further damage

In Psychiatry, the study of causation is complicated by two problems:

Causes are often remote in time from the effects that they produce e.g. childhood experience  adult anxiety disorders.a) A single cause may lead to several effects e.g. deprivation of parental affection  antisocial behavior, suicide, depression…b) A single effect may arise from several causes e.g. M.R. Depression.

Classification of Causes:  1- According to nature: a) Biological  b) Psychological c) Social


  2- According to the effect: a. Predisposing factors b. Precipitating factors c. Perpetuating (maintaining) factors

A- Predisposing factors:- Operating from early life, that determine a person’s vulnerability to causes acting close to the time of illness. -Constitution is often used to describe the mental and physical make up of a person at any point in his life  Personality is always an essential element that help to explain why the patient responds to certain stressful events and he reacts in a particular way. e.g. - Genetic endowment- Environment in utero- Trauma at birth- Social & psychological factors in infancy & early childhood.

B- Precipitating factors: Events that occur shortly before the onset of a disorder and appear to have induced it. e.g. - Physical disease - Drug - Loss of job - Changing residency


C- Perpetuating factors: These factors prolong the course of a disorder after it has been provoked. e.g. - Intrensic to the disorder (avoidance in phobic disorders) - Social circumstances (marital discords, over protecting parents).

Predisposing factors

Constitution
Illness
Recovery
Precipitating factors
Perpetuating factors

Approaches to Etiology:

1. Genetics: - Family risk studies - Twin studies - Adoption studies - Genetic causes have been studies mainly in moderate to severe mood disorders and schizophrenia.

Case presentation

23 year old female patient presents herself at the Department after a family debate.Chief complaints: „I am treated brutally by my family… I think people on the street mean bad to me…”Following examination: symptoms of anxiety, paranoid and religious delusions, acoustic hallucinations (I heard the voice of Jesus.)Question: What is the cause of her psychiatric problems according to the patient? According to you?

Questions

How do we call the decribed condition? What is the most probable diagnosis? What other diagnoses should we think of? What is the cause of her psychiatric problems according to the patient? According to you? The fundamental question of etiology: What causes the disorder? Environmental or genetic factors?


Genetic studies
Population genetics: Family studies Twin studies Adoption studies Epidemiologic studies: Genetic cohorts
Molecular methods Linkage studies Association studies Expression studies (epigenetic analyses) Animal models

Gene-Environment Interactions

Refers to the phenomenon where genetic and environmental factors both play a role in the etiology of a disease and possibly strengthen each others effect. Especially important in chronic non-communicable diseases and psychiatry. Elucidating GxE interactions can lead to better prevention and therapeutic measures. The field is connected closely to psychiatric genetics.

In summary 

Genetic and environmental factors are both extremely important in the etiology of psychiatric disorders Schizophrenia: high heritability, demonstrated gene- environment interactions for urban upbringing and cannabis use. Major depression: moderate level of heritability, Understanding gene-environment interactions is very important for the treatment as well


2. Biochemical studies: - Can be directed either to the cause of the disease or to the mechanism by which it produces its effect. - Most studies have focused on the monoamine neurotransmitters. - 5 Hydroxy tryptamine. - Noradrenaline - Dopamine

3. Endocrinology:

Hormonal changes can have profound effects or mood and behavior.

4. Neuropathology:

- Attempt to answer the question as to whether a structural change in the brain (localized or diffuse) accompanies a particular kind of mental disorder. - There is an obvious application to the etiology of dementia and other psychiatric disorders associated with organic lesions.


5. Psychological theories of etiology: a) Psychoanalysis- Provides a comprehensive range of explanation for clinical phenomena.-The central feature is the concept of unconscious mind which characterized by:a – divorce from realityb – being dynamicc – being in conflict with the conscious mind.-It is important in the etiology of neurotic disorders.-Neurosis originate from failure to pass normally through 3 stages of development oral  anal  genital.-Anxiety is the central symptom of all neurosis.-Defense mechanisms (such as rationalization and projection)are used to reduce anxiety.

b) Learning theories: Experiences in childhood and later life give rise to neurosis.

c) Cognitive theories: Symptoms and behavior are produced and maintained by maladaptive ways of thinking.