How Does Drug Use Effect the Brain?

       
Drug use in effect takes over the brain functioning.  When a person uses substances, they are using a specific part of the brain, known as the reward system.  This is the part of the brain that releases dopamines (a neurotransmitter in the brain that is responsible for use experiencing pleasure) to reinforce particular survival behaviors, such as eating and sex.  What role does drug use play in survival:  stress relief and escape.
       When a person uses a drug, such as meth, the methamphetamines trigger a release of dopamines in the reward system of the brain.  The result is a release of an incredible amount of dopamines not seen by the brain through normal brain functioning.  Over the course of time, the brain decreases the amount of dopamine natural produced in the brain.  Instead, the brain is taken over by the substance and only releases dopamines when the substance is used.  Now, substance use literally becomes the only way to feel happy or whole again for the person who is recovering.
        For the recovering person, this means that when they first get sober, they can experience low levels of dopamine when not using substances.  It takes time for the brain to recover and start replenishing the natural or normal amount of dopamines.  This is why persons in early recovery often experience feelings of boredom, or feeling down.  Persons in early recovery often return to substance use due to this defeciency in brain chemistry.  The bottom line is that people in early recovery need to stay sober, and give their brain a chance to heal.  Returning substance use only reinforces the need for substances to feel better. 
         The main part of the brain used in substance use is the reward system.  Neural pathways to other parts of the brain are "unused" and become weak. The frontal lobes are not utulized in the course of using substance, and also happens to be the part of the brain responsible for rationalizing and decision making.  This makes sense because addicts often make decisions based on getting or using substances, no matter what the cost.  As they enter into recovery, it is important for an addict to learn how to make decisions and weigh the consequences as part of a healthy decision making  process.  These new skills can help to strengthen the neural pathways to the frontal lobes of the brain.