Aetiology of Psychiatric Disorders

Dr. Khalid Bazaid, MB BS, FRCPCAssistant Professor & ConsultantChild & Adolescent Psychiatrist

College of MedicineKing Saud University

Vague but important to:

1. Diagnose and understand.

2. Allow early intervention.

3. 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

Biopsychosocial Model

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.

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. - Intrinsic to the disorder (avoidance in phobic disorders)

- Social circumstances (marital discords, over protecting parents).

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.

SocialSocial

PsychoPsycho

BIOBIO

Maintenance Maintenance PerpetuatingPerpetuatingPrecipitating Precipitating Predisposing Predisposing

EffectEffect

Nature Nature

SUPERNATURAL

Evil eye Witchcraft Possession

Islamic

vs.

Sociocultural concept

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بالتحديد أما ترد فلم منها لكل والعالمات الكيفية

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وأسبابها

الــشــرع الــشــرع في في

الشرع ● تمثل ال االجتماعية النظرة

تماما ) ( تخالف ال و تماما تطابق ال

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المجتمع المجتمع في في

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؟ العين / المـس /السحرهل ● ال أم نفسية Uأمراضا تسبب

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هل .... .... ... هل هل