Transcript Aetiology of Psychiatric Disorders

Aetiology of
Psychiatric Disorders
Dr. Fatima Alhaidar
Professor & Consultant
Child & Adolescent Psychiatrist
College of Medicine, KSU.
Vague but important to:
1.
2.
3.
Diagnose and understand.
Allow early intervention.
Optimize treatment.
In Psychiatry, the study of causation is complicated
by two problems:
1.
Causes are often remote in time from the effects
that they produce e.g. childhood experience  adult
anxiety disorders.
2.
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
Precipitating
factors
Illness
Perpetuating
factors
Recovery
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.
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.
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 reality
b – being dynamic
c – 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.
6. Social Science:
Many of the concepts used by sociologists are
relevant to psychiatry.
e.g. (1) Life events  Migration, unhappy marriage,
problems of work.
(2) Family factors  lack of social support,
criticism, and over
protection within the family.
Example:
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A 33 year old woman.
Mother of 5 children.
Presents with low mood and diminished interest in life
activities.
Divorced 8 months ago and return back to live with her
family.
Her father faces financial difficulties.
Her grand father has history of major depression.
Evil eye by a relative.