When a person is abusing fentanyl or has developed an addiction to it, several physical, psychological, and behavioral changes occur. While these changes vary from person to person, some of the observable changes can include:

  • Unexplained changes in mood, levels of irritability, or emotional reactivity, or having more mood swings
  • Changes in a person’s routine or behavior, like oversleeping, missing work, skipping meals, or withdrawing from friends
  • Changes in energy levels, like appearing more drowsy, nodding off, or sleeping more
  • Changes in appearance, including neglecting hygiene, appearing tired or ill, or losing a lot of weight
  • Inability to pay bills or needing to borrow money
  • Being evasive, secretive, or defensive about drug use or how a person is spending their time and money
  • Becoming less reliable and neglecting major responsibilities at work or home

If you are unsure if you have developed an addiction, the best course of action is to make an appointment with a licensed medical, mental health, or addiction treatment specialist. These professionals can determine whether or not you have an addictive disorder. The symptoms used to diagnose addictions include two or more of the following: [1]

  • Using more often or in higher doses than intended
  • Spending a lot of time thinking about, obtaining, using, or recovering from using the drug
  • Frequent strong drug cravings or urges to use
  • Using in situations where it is dangerous or risky (e.g., at work or while driving)
  • Experiencing conflict, tension, or strain in important relationships because of drug use
  • Neglecting responsibilities, roles, and routines because of drug use
  • Developing a tolerance (drug becomes less effective)
  • Experiencing adverse physical or mental health effects related to drug use
  • Experiencing physical or psychological discomfort or pain when cutting back, stopping, or missing a dose (withdrawal symptoms)
  • Multiple unsuccessful efforts to stop using or cut back
  • Giving up important or previously enjoyed activities to use the drug

Last updated: November 15, 2022

Hailey Shafir, M.Ed., LCMHCS, LCAS, CCS

Hailey Shafir is a licensed addiction specialist and mental health counselor. She graduated from North Carolina State University with a master of education in clinical mental health counseling in 2012, and has developed deep expertise in the areas of mental health, behavioral addictions and substance abuse. She is passionate about using this knowledge to raise awareness, provide clear and accurate information, and to improve the quality of treatment for these disorders.

Hailey is an LCMHCS (license number: S9539) under the North Carolina Board of Mental Health Counselors, and an LCAS (ID: LCAS-21333) and CSS (ID: CCS-20721) under the North Carolina Addictions Specialist Professional Practice Board.


1 American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). https://doi.org/10.1176/appi.books.9780890425596