The route not documented for PCP administration is the transdermal patch. PCP is typically used via inhalation (smoked), intranasal (snorted), or parenteral routes (injected). A transdermal patch would deliver the drug slowly through the skin, leading to gradual, unpredictable absorption and a much slower onset, which doesn’t align with the known patterns of PCP use and its rapid, dissociative effects. In practice, there are no established transdermal PCP formulations or widely recognized use via patches, whereas smoking, snorting, and injecting PCP are well documented ways people have used it.

Prenatal alcohol exposure disrupts brain development, leading to neurodevelopmental problems that fall under CNS involvement. These typically appear as intellectual disability or lower cognitive functioning, along with behavioral and self-regulation difficulties due to deficits in attention, memory, and executive function. Therefore, intellectual disability and behavioral issues best reflect the CNS impact seen in fetal alcohol spectrum disorders. Options proposing enhanced motor development, increased IQ, or no neurological issues do not fit, as CNS effects are the common pattern rather than improvements or absence of problems.

Long-acting naltrexone is an opioid receptor antagonist, meaning it blocks the effects of opioids at the receptors. The big drawback is that it is incompatible with any opioid use. If a person takes an opioid while the antagonist is active, they won’t get the usual opioid effects and can experience precipitated withdrawal because the blocker displaces the opioid from the receptors. That blockade lasts about a month, which means patients must be opioid-free before starting and must stay abstinent while on treatment. This limitation is a fundamental reason clinicians use naltrexone only after detoxification and choose it when the goal is complete opioid blockade rather than allowing ongoing opioid use for pain relief or relapse management.

Alcohol Use Disorder is defined as a medical condition in which a person has an impaired ability to stop or control alcohol use despite adverse social, occupational, or health consequences. This captures why it’s considered a disorder: the behavior persists and causes harm, and the person has difficulty stopping even when they want to or when it would be beneficial to do so. In practice, a diagnosis reflects patterns across multiple domains, not just how much or how often someone drinks. Criteria typically include craving, using more or for longer than intended, unsuccessful attempts to cut down, spending a lot of time obtaining, using, or recovering from alcohol, giving up important activities, continuing use despite problems, tolerance, and withdrawal. A clinician looks for a certain number of these signs within a year. Heavy use by itself and binge drinking describe amounts or patterns of drinking, but they don’t necessarily imply the persistent impairment and loss of control that define the disorder.