Addiction and High Risk Use

High Risk Use and Addiction

• High risk use: continued use of drugs despite severe social or legal consequences
• Characteristics:
• Temporary escape from reality becomes primary focus of life
• Unafraid or unaware of consequences of behavior
• Unbearable cravings drive behavior to obtain drugs

Addiction

• Defined as:
• Inability to control amount and frequency of drug use
• Irresistible cravings and urges for the substance
• Continued use despite adverse effects
• Denial of negative consequences
• Tendency to abuse other mood-altering drugs or alcohol
• Willingness to break the law to obtain the substance
• Tolerance and withdrawal signs and symptoms

Drug Abuse and Dependence

• Drug abuse: use of a drug in a manner not approved by the culture, resulting in social disapproval
• Non-medical drug use: recreational use of licit and illicit drugs for pleasurable effects
• Drug dependence: syndrome in which an individual continues to take a drug due to pleasurable effects, despite adverse social or medical consequences

Dose and Craving

• Dose of drug often increased to maintain desired effect (habituation or adaptation)
• Craving: uncontrolled desire to obtain and use drugs or substances an addict is dependent on

Central Pathways and Mechanisms of Dependence

• Main factors involved in drug dependence:
• Reward (reinforcing)
• Habituation
• Aversive effect on abstinence (physical withdrawal syndrome)
• Psychological changes resulting in craving
• Neurobiological basis of reward and habituation:
• Mesolimbic dopaminergic system
• Release of dopamine in nucleus accumbens (NAc) by various mechanisms

Other Transmitters Involved in Dependence

• Noradrenergic system: involved in excessive sympathetic activity following withdrawal
• Serotoninergic system: 5-HT uptake blockers or agonists decrease drug seeking behaviors
• Amino acid systems (GABAergic and glutamatergic): interact with barbiturates, BDZs, and alcohol
• Canabinoid action: via cannabinoid receptor (CB1)
• Cholinergic systems: nicotine interacts with

Mechanism of Habituation

• Chronic use of drugs increases adenylate cyclase in N.Acc., leading to increased cAMP, G-proteins, and protein kinases
• Protein kinases control activity of ion channels, leading to changes in neuronal activity