Chapter 18 Psychoactive Substance Use Disorders: Drugs

Description of the Disorder Drug use is a prevalent and pervasive issue in the United States SUDs incur a huge cost to society. – $484 billion annually In 2008, about 22.2 million individuals were classified with substance dependence or abuse as defined by DSM-IV-TR Associated with increased risk-taking behavior

Clinical Picture SUDs may result from single or multiple substances Classes of drugs: – Cannabinoids – Hallucinogens – Depressants – Opioids – Stimulants – Inhalants – Dissociative anesthetics

Diagnostic Considerations Maladaptive pattern of behaviors related to substance use Four categories of maladaptive behaviors: 1.Impaired control 2.Social impairment 3.Risky use 4.Pharmacological criteria

Impaired Control Unsuccessful attempts to cut back Taking more than planned Longer duration of use Craving or a perceived need to engage in substance use Craving may consume one’s thoughts

Social Impairment Inability to carry out needs of daily life Failing to fulfill obligations Engaging in substance use rather than social activities Persistent use in spite of negative social impact

Risky Use Continued use when known danger exists Dangerous situation Likely physiological consequences

Pharmacological Criteria Tolerance: State that develops wherein the user needs progressively larger doses of the drug to feel the desired effect Withdrawal: Physical response to specific substances that can occur after extended, consistent use

Epidemiology 8% of Americans over the age of 12 report illicit drug use – Rates of marijuana use are rising, particularly among youth 1.8 million admissions to treatment in 2007 – Largely for alcohol use or alcohol and a secondary substance

Psychological and Biological Assessment Important to assess for other psychological disorders, given the high rate of comorbidity – Assessing for daily impairment and readiness to change may provide useful information for treatment – Functional analysis may also be beneficial – Outcome assessments should be performed to monitor progress Biological methods include: – Urinalysis – Blood, saliva, and hair testing

Etiological Considerations Behavioral genetics – Genetic factors account for a significant portion of the variance in substance use disorders – Genetic influence appears to increase over time until middle adulthood Molecular genetics – Strongest single-gene effects have been found for polymorphisms of the ALDH and ADH genes in Asian samples – GABA receptor genes on chromosome 4 and substance abuse – Polymorphisms in dopamine receptor genes

Etiological Considerations cont. Gene–environment interactions – Stress, the DRD2 gene, and alcohol dependence – MAOA, childhood maltreatment, and alcohol use problems – More environmental measures need to be utilized in genetic studies

Etiological Considerations cont. Brain reward circuits are associated with increased risk – Enhanced activity in regions often associated with reward systems Chronic drug administration is associated with alterations in this system, including decreased extracellular dopamine and reduced D2 receptor availability Brain stress circuits – Greater reactivity in the HPA axis of rats has been associated with greater self-administration of addictive substances – HPA axis activation also associated with increased dopaminergic neurotransmission in reward circuits

Etiological Considerations cont. Neuroadaptation in reward and stress circuitry – Reward and stress circuits become dysregulated with chronic drug use, which creates a state of negative affect when the drug is not used, thus increasing the reinforcing properties of the drug – Users have difficulty dealing with stress when the circuit becomes dysregulated

Etiological Considerations cont. Learning and modeling – Drugs are reinforcers Use increases in environments devoid of alternative forms of reinforcement Life events – Chronic stress contributes to both initiation and maintenance of drug use – Emotional stressors associated with greater vulnerability to SUDs

Etiological Considerations cont. Cognitive influences – Expectancies Relationship between positive expectancies and substance use Negative expectancies associated with maintaining abstinence from use – Executive functioning Drug use alters executive functions (e.g., decision making and attention)

Etiological Considerations cont. Sex – Men and women differ in their pathways to drug addiction Women are less likely to have an SUD, and onset is often later in life; however, they become dependent more quickly and experience more severe consequences Men and women have different barriers to treatment Racial/ethnic factors – Minorities in inner cities are particularly vulnerable to drug use – Reduced access/use of community services for treatment

Course and Prognosis Development and progression of substance use among adolescents is debated in the literature – “Gateway theory” Risk factors include age of initiation and frequency of use during adolescence – Others include mood/anxiety disorders and certain personality disorders Recovery is notoriously difficult once an SUD is present

Course and Prognosis Treatment outcome – Influenced by: Severity of addiction Individual characteristics Length of stay in treatment – Recovery is a long-term process