Although each drug causes unique physiological and neurological effects, all drugs overlap in one important way, All drugs cause changes in the brain, some in ways that may be long-lasting or even permanent. These brain changes can have significant effects on mood and cause depression, ultimately lessening a person's ability to lead their best and healthiest life. Your brain regulates all the body's basic functions, including every breath and each heartbeat, while enabling you to interpret and respond to experience. It shapes thoughts and emotions and determines your behavior. Despite some commonality, the short- and long-term health effects of drugs are distinct, with each one potentially affecting life spans in a different way. Opioids include heroin and prescription pain relievers such as oxycodone, hydrocodone, codeine, morphine and fentanyl. All members of the same chemical family, these drugs interact with the opioid receptors on nerve cells in both the body and the brain. Out of everyone who tries heroin for the first time, nearly one in four become addicted. Repeated heroin use changes the physical structure Wang, X et al., (2012) and physiology of the brain, creating long-term imbalances in neuronal and hormonal systems that are not easily reversed Ignar, D. M et al., (1990) & Kreek, M. J et al., (1984). Studies have shown some deterioration of the brain’s white matter due to heroin use, which may affect decision-making abilities, the ability to regulate behavior, and responses to stressful situations Li, W et al., (2013), Qiu, Y et al., (2013) & Liu, J et al., (2011). Heroin also produces profound degrees of tolerance and physical dependence. Tolerance occurs when more and more of the drug is required to achieve the same effects