Week 5: The Nature and Causes of Psychological Disorders Part 2
SUBSTANCE- RELATED DISORDERS
Substance- use disorders
Psychoactive substance: A chemical substance that acts upon the central nervous system where it
affects brain function, changing a person’s emotions, perceptions, or thoughts
Examples: Alcohol, drugs, caffeine,
Substance dependence occurs when…
An individual's repeated use results in "tolerance
withdrawal and compulsive drug-seeking
behaviour"; includes difficulty cutting back
despite wanting to do so.
Substance abuse is diagnosed when a person's
repeated use of a substance results in serious
A diagnosis is made when the individual’s repeated use of the substance results in serious
adverse consequences. In order to be diagnosed with substance abuse the individual must meet
one of the following:
1. Repeated failure to fulfill important obligations as a result of the substance (e.g. missing work)
2. Repeated use of the substance in a situation that is dangerous (e.g. drinking and driving)
3. Repeated legal problems related to the substance (e.g. being arrested for public intoxication)
4. Continued use of the substance despite it causing problems in the individual's social or
interpersonal relationships (e.g. frequent fights with a partner while intoxicated regarding usage)
Substance- induced disorders
Substance intoxication: Occurs when a person suffers clinically significant negative or harmful
behavioural changes or psychological effects because of the influence of a psychoactive
Substance withdrawal: Occurs when a person suffers clinically significant negative or harmful
behavioural changes or psychological effects because they recently stopped prolonged use of a
Criteria when making a substance- related disorder diagnosis ~
o Repeated intoxication o Tolerance o Degree to which
o Withdrawal o Difficulty quitting problems result
symptoms o General well being Substance- induced mental disorders ~
o Sleep disorders
Noted symptoms include ~
Positive and negative symptoms
Positive symptoms: Positive symptoms such as delusions or hallucinations usually reflect
an excess or distortion of a normal brain function.
Negative symptoms: Negative symptoms such as slowed speech or movement normally
reflect a diminution or loss of normal brain function.
NOTE - (positive = presence and negative = absence)
Psychosis: Conditions which affect the mind whereby there has been a loss of contact
Schizophrenia and schizophreniform disorders
Schizophrenia has five main subtypes, all which have different symptoms. However, all are
characterized by the presence of at least two of the following:
Grossly disorganized or catatonic behaviour
Negative symptoms (e.g., flattened affect, decrease in production of speech) Schizophreniform disorder: A psychological disorder where the individual experiences the
symptoms of schizophrenia for a period of only one to six months.
Schizoaffectic disorder: A psychological disorder where a person experiences a mood episode
such as depression or mania at the same time that he/she is exhibiting symptoms of
schizophrenia such as hallucinations or delusions.
Biological bases ~
Schizophrenia is a pervasive illness, affecting perception, emotion, cognition, motivation, etc.
The diathesis-stress model tells us that it most likely results from a combination of
predispositions and environmental stress. This combination provides biochemical and anatomical
change in the brain.
Dopamine is one of the chemicals used in the brain to communicate among brain cells. A