Addiction to psychoactive drugs
- Factors contributing to addiction:
1. Dopamine secretion: drugs that are addictive stimulate synapses involving dopamine, which makes the user feel pleasure because dopamine activates the reward pathway.
2. Genetic predisposition: although specific genes are still unknown, addiction to psychoactive drugs is thought to be hereditary, like with alcoholism
3. Social factors: cultural tradition, peer pressure, traumatic circumstances/experiences, deprivation, mental health issues can encourage and even enhance addiction to psychoactive drugs but it can also prevent it
- Examples
- Cocaine
- Excitatory psychoactive drug
- Highly addictive
- Mechanism
- once in the body, it binds to membrane proteins involved in reuptake of dopamine
- dopamine cannot be absorbed by the presynaptic neuron anymore, resulting in an increased concentration of dopamine in the synapse
- hence, cocaine users’ reward pathway is artificially stimulated, leading to constant euphoria
- cocaine-induced depression can occur because of increased tolerance and adaptation by the body, which decreases the secretion of dopamine by the brain
- Crack: vaporous so easy uptake into body and stronger effects
- Cocaine
- THC (tetrahydrocannabinol)
- Chemical in cannabis that causes most of the psychoactive effects
- Receptors are in many places in the brain
- cerebellum, hippocampus, cerebral hemisphere
- Mechanism
- it binds to cannabinoid receptors, which is at a synapse where signaling chemicals are released by postsynaptic neuron to bind to presynaptic neuron
- THC blocks release of excitatory neurotransmitters
- hence, THC is an inhibitory psychoactive drug
- General effects
- psychomotor behavior, short-term memory is disrupted
- appetite stimulated
- other effects noted by users