SUBSTANCE-RELATED DISORDERS
Description
Substance use disorders are a cluster of disorders in which cognitive, behavioral, and
physiological symptoms indicate that a person continues using a substance despite
significantsubstance-related problems
Psychiatric symptom clusters may be related to substance use, discontinuation of substance
use,or withdrawal from habitual substance use.
Substance use disorders lead to changes in brain circuits and physiological functions that lead
toa need for detoxification and a possible need for long-term treatment.
The word substance can describe a drug of abuse, a medication, or a toxin that produces
psychoactivation and alters cognitive, behavioral, and affectiveperceptions.
Dependence: repeated use of a substance with or without physical dependence
Abuse: use that is inconsistent with sociality use patterns
Misuse: usually applies to a prescribed substance
Intoxication: reversible syndrome caused by a specific substance affecting memory, judgment,
behavior, or social or occupational functioning
Withdrawal: substance-specific symptoms that occur after stopping or reducing use
Tolerance: needing more of the substance to get the desired effect
Etiology
Multiple theories ranging from psychological to
neurobiologicalProbable multifactorial etiological profile
Two common types of theories: psychodynamic and biological
Psychodynamic theory
Behaviors of abuse are seated in oral-stage fixation.
A person seeks gratification through oral
behaviors.
Maladaptive regressive behaviors can become overlearned, fixed, and reinforced
throughdysfunctional family patterns.
Sociocultural factors attempt to explain population-based differences in substance abuse rates.
,Biological theory
Genetic loading
People with a strong genetic vulnerability to addiction are thought to have defects in the
workingof the reward center of the brain, which predisposes them to stronger-than-normal
positive rewards that draw them to substance use.
Gender differences
Ethnic differences
A person is predisposed to stronger-than-normal negative rewards, making it more
difficult to stop abuse once it has begun.
Involves two neurobiological processes:
1. Reinforcement
Brain-based changes in structure and function can lead to addictive behavior.
The process of positive and negative rewards is physiologically linked to
memoryfunction.
Changes appear to occur with any drug of abuse.
Reinforcement results in “feel good” sensations when a drug of abuse is used and in
“feelbad” sensations when the drug exits the body.
Positive rewards of reinforcement result in the social rewards commonly associated with
drug use, such as disinhibition, euphoric mood, and anxiety reduction. Mediated by
dopamine (DA) pathways.
Negative rewards are aversive, such as increased anxiety and dysphoria. Mediated by
thegamma amino butyric acid (GABA) pathways .
Reinforcement occurs in the ventral tegmental area and the nucleus accumbens of
thebrain, collectively called the reward center.
DA release within the reward center is enhanced further by the release of natural
morphine-like neurotransmitters called neuropeptides (enkephalins, beta-
endorphins).
Neuropeptides further enhance the reinforcing pleasure experienced by the
person.With repeated drug use, the DA system becomes increasingly sensitized.
Eventually, associated drug use stimuli (e.g., pictures of drug paraphernalia) can cause
DA release, leading to reinforcement of use and often to increased drug use.
2. Neuroadaptation
Brain-based changes in structure and function can lead to tolerance and withdrawal.
, Drug-specific alterations in the normal level and function of neurotransmitters occur as
thebody adapts to the chronic presence of the substance of abuse.
Neuroadaptive processes become very significant when the person stops substance use.
These processes become the basis for withdrawal symptoms, because adaptive responses
areunopposed when the substance is no longer present.
Neuroadaptive changes may be more enduring in some persons, possibly lasting for
years,thus increasing their potential for relapse.
This concept helps to explain why, after a long period of sobriety, a person who returns to
substance abuse often picks up at the same level of tolerance and physical impact as
experienced before sobriety.
Incidence and Demographics
Persons age 18 to 24 years of age have high prevalence rates for using most substances.
The United States has higher rates of substance use than any other developed country.
More than 50% of U.S. clients with a psychiatric disorder have a comorbid substance
usedisorder.
Persons with schizophrenia are 4 times more likely to have a substance use
comorbiditythan the general population.
Persons with bipolar affective disorder are 5 times more likely to have a substance use
comorbidity than the general population.
More than 2 million admissions annually are made to inpatient substance use
treatment facilities.
Though now legal in some states, marijuana is the most commonly abused
illegalsubstance.
Alcohol is the most commonly abused legal substance.
Rates are higher in men than in
women.90% of men have used alcohol.
70% of women have used alcohol.
Rates are highest in African Americans, Hispanic Americans, and Native Americans; rates
are lowest in Asian Americans.
55% of fatal driving accidents in the United States occur with a driver under the influence
ofalcohol.
50% of crimes in the United Stated are committed under the influence of alcohol.
The lifetime risk for alcohol use disorder is 15% in the general U.S. population.
Risk Factors