Mechanism of Illicit Drug Use Characterized by Rapid Increase in Dosage or Frequency
The mechanism of illicit drug use characterized by a rapid increase in drug dosage or frequency is spiraling (option A). 1
Understanding Spiraling in Substance Use Disorders
Spiraling is a pattern of drug use where individuals progressively increase their consumption to achieve desired effects due to developing tolerance. This pattern is driven by several key neurobiological mechanisms:
Neuroadaptation and Tolerance Development
- With repeated exposure, the brain adapts to the drug, requiring higher doses to achieve the same effect
- Disruption of dopamine-modulated striatocortical pathways impairs prefrontal cortical function necessary for self-regulation and control 1
Mesolimbic Dopamine Pathway Involvement
- Initial drug use triggers dopamine release in the nucleus accumbens, creating pleasurable effects
- Repeated exposures lead to neuroadaptations that escalate drug use and impair self-control
- These changes can persist for years after drug discontinuation, making addiction a chronic brain disease 1
Health Risks of Spiraling Drug Use
Spiraling significantly increases several serious health risks:
- Overdose risk: Drug overdose is a leading cause of mortality among persons who inject drugs illicitly 1
- Respiratory depression: Particularly concerning with opioids like methadone, which can cause dangerous respiratory depression, especially at escalating doses 2
- Incomplete cross-tolerance: When users switch between different opioids, incomplete cross-tolerance can lead to overdose even in patients with high opioid tolerance 2
- Compounded risks with polydrug use: Combining substances (common in spiraling patterns) increases risks of respiratory depression, hypotension, profound sedation, or coma 2
Genetic Factors Influencing Spiraling
The COMT Val/Val genotype is associated with higher addiction risk compared to the COMT Met/Met genotype due to:
- Lower cortical dopamine levels affecting reward processing and executive functioning
- Impaired executive functioning and self-regulation
- Greater vulnerability to neuroadaptations that lead to escalation of substance use 1
Treatment Approaches for Spiraling Drug Use
For patients exhibiting spiraling patterns of drug use, especially with opioids:
- Medication-assisted therapy with methadone, buprenorphine, or naltrexone can significantly improve outcomes 1
- Careful monitoring is essential as these patients are at high risk for continued drug-seeking behaviors including "doctor shopping" and prescription tampering 3
- Recognition of withdrawal risk is important, as abrupt discontinuation in physically-dependent patients can trigger withdrawal syndrome characterized by restlessness, lacrimation, rhinorrhea, perspiration, chills, myalgia, and mydriasis 3
Distinguishing from Other Patterns
It's important to differentiate spiraling from other patterns of drug use:
- Cycling: Alternating between periods of use and abstinence rather than continuously increasing dosage
- Pyramiding: Gradually increasing doses to a peak, then tapering down
Caution in Clinical Practice
When treating patients with potential spiraling drug use:
- Assess for "drug-seeking" behaviors including emergency calls near end of office hours, refusal of appropriate examination, repeated "loss" of prescriptions, and reluctance to provide medical records 3
- Consider genetic factors and family history when assessing addiction risk 1
- Implement careful record-keeping of prescribing information, including quantity, frequency, and renewal requests 3
- Be aware that adolescents are at particularly high risk due to enhanced neuroplasticity of their developing brains 1