Wize University Psychology Textbook > Consciousness
Psychological & Physical Dependence
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Psychological & Physical Dependence
Physical dependence - nervous system has become dependent on the drug for physical functioning.
Increasing dose required for functioning.
Loss of access to the substance results in withdrawal symptoms: Fever, chills, tremors, convulsions, vomiting, cramps, diarrhea, pain, fatigue, apathy, irritability, depression, disorientation.
Psychological dependence - mental and emotional craving for a substance.
Psychological and physical dependence are separate - you can have one without the other. Psychological dependence is not less serious than physical dependence.
Drug Addiction and the Reward Pathway in the Brain
Many drugs affect the reward pathway in the limbic system, which increases the likelihood of addiction.
The key components of the reward pathway are the ventral tegmental area (VTA) in the midbrain and the nucleus accumbens in the basal ganglia. The VTA releases dopamine into the nucleus accumbens, resulting in feelings of pleasure.
When our brain is exposed to chronically high levels of dopamine due to drug use, it adjusts and produces less dopamine. This then makes it harder to feel pleasure and reward in the absence of the drug.
Practice: Psychological & Physical Dependence
Robert is a habitual heroin user. When he does not take heroin, he experiences chills, fever, tremors, and heart palpitations. These are signs that Robert is experiencing: