Over 100,000 researchers, educators, clinicians and students support the association through their membership. Their mission "is to advance the creation, communication and application of psychological knowledge to benefit society and improve people's lives." APA supports 54 divisions, two of which pertain to addictions. Division 50, Society of Addiction Psychology promotes advances in research, professional training, and clinical practice within the range of addictive behaviors. Addictive behaviors include problematic use of alcohol, nicotine, and other drugs as well as disorders involving gambling, eating, spending, and sexual behavior. Division 28, Psychopharmacology and Substance Abuse promotes teaching, research, and dissemination of information regarding the effects of drugs on behavior. The College of Professional Psychology (CPP), hosted by the American Psychological Association Practice Organization, previously offered a certificate to psychologists whom demonstrated proficiency in the psychological treatment of alcohol and other substance-related disorders. The CPP maintains the certificate of proficiency for persons who acquired it prior to 2011. The Society of Addiction Psychology certificate will be re-instated while the Society examines other avenues for credentialing professionals in addiction treatment. It seems that wherever one finds intoxication, one likely will find addiction. Recently researchers have argued that the addiction process is like the disease model, with a target organ, a defect, and symptoms of the disease. In other accounts, addiction is a disorder of genes, reward, memory, stress, and choice. The Disease Model in Addiction  According to the new disease model, rather than being a disease in the conventional sense, addiction is a disease of choice. That is, it is a disorder of the parts of the brain necessary to make proper decisions. As one becomes addicted to cocaine, the "ventral tegmentum nucleus accumbens" in the brain is the organ. The defect is stress-induced hedonic regulation. Understanding the impact that genes, reward, memory, stress, and choice have on an individual will begin to explain the Disease Model of Addiction  Genetic  The genetic makeup of an individual determines how they respond to alcohol. What causes an individual to be more prone to addiction is their genetic makeup. For example, there are genetic differences in how people respond to methylphenidate (Ritalin) injections. Reward  Increased dopamine is correlated with increased pleasure. For that reason, dopamine plays a significant role in reinforcing experiences. It tells the brain the drug is better than expected. When an individual uses a drug, there may be a surge of dopamine in the midbrain, which can result in the shifting of that individual's pleasure “threshold” (see figures one and two).