Test: Drug Dependence - 1 - MCAT MCQ

The gene variant that causes slower metabolization of acetaldehyde leads to a buildup of acetaldehyde in individuals who consume alcohol. Acetaldehyde is a toxic byproduct of alcohol metabolism that can cause unpleasant symptoms such as facial flushing, rapid heartbeat, nausea, and dizziness. These adverse effects create an aversive reaction to alcohol consumption, making it less enjoyable and potentially discouraging excessive alcohol intake. Therefore, individuals with this gene variant are more likely to experience negative effects from alcohol, which can lower the likelihood of alcohol abuse in cultures where the gene variant is prevalent, such as China and Japan.

Caffeine belongs to a class of general stimulants, which all increase the metabolic activity in cells. What is the process that causes jitters from excess amounts of coffee or other highly caffeinated beverages?
A.Caffeine inhibits an enzyme that breaks down cyclic adenosine monophosphate (cAMP). The increase in cAMP increases glutamate production. This increase in cellular activity results in action potentials that are briefer and released in bursts.
B.Caffeine inhibits an enzyme that breaks down dopamine. The increase in dopamine increases GABA production. This increase in cellular activity results in action potentials that are briefer and released in bursts.
C.Caffeine inhibits an enzyme that breaks down serotonin. The increase in serotonin increases glutamate production. This increase in cellular activity results in action potentials that are briefer and released in bursts.
D.Caffeine inhibits an enzyme that breaks down norepinephrine. The increase in norepinephrine increases GABA production. This increase in cellular activity results in action potentials that are briefer and released in bursts.

Haloperidol is not a hallucinogen but rather an antipsychotic medication commonly used to treat psychotic disorders such as schizophrenia. It works by blocking dopamine receptors in the brain. While haloperidol can have its own side effects, it is not known to cause hallucinogen persisting perception disorder (HPPD) upon cessation of use.

On the other hand, marijuana, mescaline, and LSD are hallucinogenic substances that have been associated with HPPD. HPPD involves the re-experiencing of altered perceptions, such as visual disturbances or distortions, even after the use of hallucinogens has stopped. These symptoms can persist for weeks or longer and can significantly impact daily functioning.

The representativeness heuristic is a cognitive bias in which individuals make judgments or decisions based on how well an object or event matches a particular prototype or stereotype. In this case, Emily is using the representativeness heuristic by basing her beliefs about her own drug usage on the example of her friend who used heroin without apparent problems. She assumes that because her friend did not experience any problems with heroin use, she will also be safe from overdosing or other negative consequences. This heuristic can lead to flawed reasoning as it does not consider individual differences, variations in drug potency, or the potential risks associated with heroin use.

The route of entry with the highest addiction potential is intramuscular injection. When drugs are injected intramuscularly, they are directly delivered into the muscle tissue, allowing for rapid absorption into the bloodstream. This results in a quick onset of effects, which can be highly reinforcing and increase the risk of addiction.

Intramuscular injection bypasses the slower absorption process of oral ingestion and provides a more immediate and intense drug effect. This rapid delivery to the brain's reward pathways can lead to a higher potential for addiction. Additionally, the act of injecting drugs can also contribute to the addictive behavior, as it can become associated with the drug-seeking and drug-taking process.

It is important to note that addiction potential can vary depending on various factors, including the specific drug, individual differences, and other circumstances surrounding drug use.

The mesolimbic pathway is a neural pathway involved in reward and motivation. It is primarily associated with the release of dopamine, a neurotransmitter that plays a crucial role in the brain's reward system. In the mesolimbic pathway, dopamine is produced in the ventral tegmental area (VTA) of the midbrain.

From the VTA, dopamine is transmitted to various target regions, including the nucleus accumbens, the amygdala, and the hippocampus. These areas are involved in processing reward, emotion, and memory. The release of dopamine in these target regions reinforces pleasurable experiences and motivates behavior associated with reward-seeking.

Option A accurately describes the mesolimbic pathway, highlighting the production of dopamine in the VTA and its transmission to the nucleus accumbens, amygdala, and hippocampus. This pathway is essential for the processing of reward and motivation in the brain.

The inaccurate statement is D. Withdrawal symptoms do not typically show little improvement until a week after cessation of alcohol consumption. The peak of alcohol withdrawal symptoms usually occurs within the first 24 to 72 hours after the last drink. Symptoms such as tremors, anxiety, insomnia, and agitation are most severe during this time.

After the peak period, withdrawal symptoms generally begin to subside and show improvement over time. While individual experiences may vary, significant improvement is often observed within the first week of alcohol withdrawal. Symptoms such as sleep disturbances and anxiety may persist for a longer duration, but they typically diminish gradually rather than reaching their peak after a week.

It's important to note that alcohol withdrawal can vary in severity and duration depending on factors such as the amount and duration of alcohol use, individual differences, and any underlying medical conditions. Medical supervision and support are crucial during the withdrawal process to ensure safety and appropriate management of symptoms.

The described study is a 3 x 2 factorial design. In a factorial design, multiple independent variables (factors) are manipulated simultaneously to examine their individual and combined effects on the dependent variable.

In this study, the independent variables are:

• Ibogaine dose: 40 mg/kg or 80 mg/kg
• Administration of glycine: Administered or not administered
• The dependent variable is the withdrawal behavior, specifically operationalized by increased jumping behavior in morphine-dependent mice.

The study involves three levels of the ibogaine dose factor (40 mg/kg, 80 mg/kg, and control) and two levels of the glycine factor (administered or not administered). By manipulating these factors, the researcher can observe the effects of ibogaine and glycine on withdrawal symptoms individually and in combination.

This design allows the researcher to assess the main effects of each independent variable (ibogaine dose and glycine administration) as well as their interaction effect. The significant inhibition of withdrawal symptoms in the 80 mg/kg ibogaine group and the reversal of effects with glycine demonstrate the interaction effect between the two factors.

Therefore, the study described is a 3 x 2 factorial design.

The statement highlights a potential problem with the efficacy of 'per se' cannabis DUI laws. Cannabis metabolites, such as THC-COOH, can remain in the bloodstream for an extended period, even after the psychoactive effects of cannabis have worn off. Therefore, detecting the presence of cannabis metabolites in a driver's blood does not necessarily indicate impairment at the time of testing. This poses a challenge in accurately determining whether a driver is currently under the influence of cannabis and impaired or if they simply used cannabis at some point in the past.

Option A is not accurate because blood testing for impairment can be conducted, although it may not be feasible or routinely performed during a traffic stop.

Option C is not accurate because quantifying the precise amount of THC that causes impairment is a complex task and subject to individual variations, making it challenging to establish a universally applicable threshold.

Option D is not accurate because the statement contradicts established research and the consensus that driving under the influence of cannabis can impair driving performance and increase the risk of accidents.

Both alcohol and benzodiazepines have similar effects on the central nervous system (CNS) by enhancing the activity of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter. Prolonged use of either substance can lead to tolerance to the effects of both drugs. This means that individuals who develop tolerance to alcohol may also show reduced sensitivity to benzodiazepines, and vice versa, due to cross-tolerance.

Cross-tolerance occurs when the tolerance developed to one drug extends to another drug with a similar mechanism of action or effects. In the case of alcohol and benzodiazepines, both substances enhance GABA activity, and long-term use can lead to adaptive changes in the GABA receptor system, resulting in cross-tolerance between the two substances.