Aetiology of Psychiatric Disorders

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Aetiology of Psychiatric Disorders

• Dr. Fatima Al-Haidar
• Associate Professor Consultant
• Child Adolescent Psychiatry
• College of Medicine, KSU.

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Vague but important to

• Diagnose and understand.
• Allow early intervention.
• Optimize treatment.

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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 neurotic 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.

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Classification of Causes
1- According to nature
a) Biological
b) Psychological
c) Social
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2- According to
the effect a. Predisposing
factors b. Precipitating
factors c. Perpetuating
(maintaining) factors
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• A- Predisposing factors
• - Operating from early life, that determine a
  persons 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.

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• 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

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• 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).

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Predisposing factors
Constitution
Illness
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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.

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• 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

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• 3. Endocrinology
• Hormonal changes can have profound
  effects or mood and behavior.

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• 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.

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• 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.

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

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

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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.

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Example

• - Nada is 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.
• December 2006 / wendell