Here are a few of the many possible specialty areas for psychology majors Click the links below for more information:

Behavioral Psychology - concerned with measurable behaviors, operant conditioning, classical conditioning, and reinforcement.
Biological Psychology - uses a bottom-up approach, examining the biology that underlies psychological conditions, mental processes and addiction.
Clinical Psychology - The study and application of psychological information in a clinical setting to help individuals
Counseling psychology - Usually involves working with a client or clients to help them with psychological issues.
Criminal Psychology - Studies criminal behavior and the psychology of dangerous and violent offenders. Sometimes helps police by creating a psycholgical profile of a wanted criminal.
Developmental Psychology - Studies the normative changes that occur in development. They study Eriksons developmental stages, and things like attachment theory.
Environmental Psychology - Studies the interactions between people and their environments.
Evolutionary Psychology - Studies how cognitive processes and brain funcions relate to evolutionary pressures.
Forensic Psychology - The application of psychological principles to law.They testify in criminal cases, provide research in court about the accuracy of statements, and give psychological examinations.
Health Psychology - Studies the link between psychology and health. Looks at biological, psycholgical, and social factors influencing health.
Humanistic Psychology - Views people as generally good, and looks at ways to help them grow. Focuses on the client's capacity for self-direction, and understanding their own development.
Industrial organizational psychology - works on improving the functions of a system. Optimizes peformance of workers, and businesses. They streamline tasks, reorganize things, improving working conditions with things like plants, coffee, suggestion boxes, etc...
Neuropsychology - Studies the brain in order understand behavior. Sometimes works with animal models to understand things like addiction, depression, learned helplessness, and more. Research in this field is currently having a big impact on all areas of psychology.
Research Psychology - Does reseach and statistical analysis. Focuses on conductiong studies, collecting research data, data analysis, and getting publications.
School Psychology - Helps students in schools, sometimes works as school counselors, creates programs to improve performance and help children who are stuggling
Social Psychology - Studies the social influences on behavior and mental processes. Looks at what happens in social situations, social learning, etc.
Sports psychology - works to improve the body, and optimize performance in sports and exercise.

Neurobiology of Drug Addiction:

Synopsis of Incentive Sensitization Theory

There are many competing theories describing the mechanisms by which neuroadaptions occur in relation to chemical dependence and addiction. The theories on neuroadaptions presuppose that chemical dependence is related to synaptic plasticity changes that take place within the limbic system, and especially within the mesolimbic dopamine system (MDS). Many neurobiologists believe that dysregulations in certain pathways within the MDS, related to genetic and environmental causes, can create a biological sensitivity to developing a chemical addiction to a certain drug. The neuroadaption theories attempt to explain the type of changes that take place within the limbic system, in the hopes of ultimately discovering innovative new ways to helping people suffering from chemical addiction.
Incentive Sensitization Theory (IST) is currently the most popular theoretical explanation of how and where the neuroadaption occurs for animals that have become chemically dependent. IST is popular because it is backed up with strong research support, and the ability to explain or predict many facets of addiction. IST says that neuroadaption occurs in pathways related to the, “wanting,” of the drug more than the, “likeing,” of the drug’s effects. IST is supported by the fact that many chemically addicted people report that they no longer especially enjoy the effects of the drug, but still have intense cravings to go get the drug and use it. Chemical addiction seems to rely on pathways intended to motivate people to continually, and compulsively seek food, water, and sex, even when such attempts are frequently unsuccessful...

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