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How Does Addiction Affect Behavior?


Addiction, also known as substance use disorder (SUD), is listed in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) as a chronic, relapsing brain disorder. Substance use disorder is defined as a “complex condition in which there is uncontrolled use of substance despite harmful consequence.” While the specific reason behind why an individual develops an addiction remains unknown, the National Institute on Drug Abuse (NIH) have identified several risk factors that have been reported to increase one’s propensity for developing substance use disorder. An individual struggling with addiction will prioritize satisfying her cravings above all else, as drugs or alcohol become the central focus of one’s life, she will demonstrate a preference for these substances over relationships, school, work, and even life itself. There are a variety of behavioral changes that are caused by addiction. Some of the signs exhibited by an individual struggling with addiction and behavioral changes that may occur due to substance use disorder could include, but are not limited to, the following examples, provided by the American Psychiatric Association

  • Emotionally unstable
  • Hyperactive 
  • Hostile 
  • Uncommunicative
  • Uncooperative 
  • Depressed
  • Agitated
  • Anxious
  • Avoids eye contact
  • Increased need for privacy
  • Irregular eating habits (eats excessive amounts or does not eat at all)
  • Random laughing fits
  • Disappears for extended periods of time
  • Lacks coordination
  • Financial difficulties
  • Attempts to cover up breath with mints and/ or gum
  • Loss of inhibitions
  • Difficulty focusing
  • Reckless and dangerous behaviors (e.g., driving while intoxicated)
  • Uses eye drops to reduce eye reddening
  • Shift in sleeping habits (e.g., periods of sleeplessness, followed by extended periods of sleep).
  • Failure to honor previously made commitments 
  • Loss of interest in once enjoyed hobbies or pastimes
  • Self-imposed social isolation and withdrawn
  • Deceitful

Addiction can change how certain areas of the brain function. Habitual abuse of drugs can cause the amygdala, area of the brain that perceives feelings of stress, anxiety, and irritability, to become increasingly sensitive. When an individual begins to experience withdrawal as a substance leaves his body, in attempt to mitigate the discomforts of the withdrawal symptoms she will experience drug cravings and be motivated to satisfy her cravings. The basal ganglia, sometimes referred to as the brain’s reward circuit, is an area in one’s brain that plays a role in cultivating motivation, the formation of routines and habits as well as appreciating the pleasurable effects of life. Drugs can cause this area to become over-active which is often experienced as a feeling of euphoria. With repeated exposures, neural pathways will form around the presence of the substance, which can reduce one’s sensitivity and make it more difficult to glean pleasure from anything other than the substance. 

For Information and Support 

Substance abuse and addiction can be incredibly dangerous and can result in severe short and long-term consequences. If you or someone you know is suffering from substance abuse or addiction, please get help as soon as possible. The earlier you seek support, the sooner you and your loved ones can return to leading happy, healthy, and fulfilling lives. There is no reason to go through this alone, and we are here to help. Please feel free to reach out to us for further information or with any questions regarding substance abuse or addiction. We are available anytime via telephone at: 213-389-9964, or you can always email us at:

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