Drugs, Behavior, and Major Depressive Disorder

Classical Conditioned Tolerance

Tolerance developed through repeated drug exposure in same context.

Analgesia

Pain relief effect from morphine administration.

Paw Lick Latency

Time taken for a subject to lick paws after discomfort.

Behavioral Tolerance

Reduced response to a drug due to conditioning.

Heroin Overdose

Increased risk when used in unfamiliar environments.

Lethal Dose

Normal heroin dose: 200-400 mg; addicts: 1800 mg.

Drug Sensitization

Increased drug effects from repeated administration.

Reverse Tolerance

Increased effects observed after repeated drug use.

Incentive Sensitization Theory

Increased motivation to use drugs due to sensitization.

Placebo Effect

Therapeutic response from pharmacologically inactive substances.

Active Placebo

Produces some response but less than active drug.

Major Depressive Disorder

Mood disorder with increased prevalence in recent decades.

Monoamine Theory

Depression linked to serotonin, NE, and dopamine levels.

Neurogenic Theory

Depression as a reversible disorder affecting brain structure.

Hippocampal Atrophy

Reduction in hippocampal volume linked to chronic stress.

BDNF

Brain-derived neurotrophic factor crucial for neuron survival.

Corticotropin Releasing Factor (CRF)

Elevated in depressed patients, linked to stress response.

Neurogenesis

Formation of new neurons, particularly in the hippocampus.

Chronic Inflammation

Linked to depression, obesity, and gut bacteria imbalance.

Therapeutic Lag

Delay in drug effects, typically 2-4 weeks.

Double Blind Study

Neither participants nor researchers know treatment assignments.

Single Blind Study

Only researchers know treatment assignments.

Neural Adaptations

Changes in receptor sensitivity due to drug exposure.

Stress Response

Overactive HPA axis linked to depression and anxiety.

Causal Relationship

Depression can lead to alcohol use and vice versa.

Comorbidity

50% of depressed individuals also have anxiety disorders.

Electroconvulsive Therapy (ECT)

Effective for depression but may cause temporary memory loss.

Therapeutic Effects of Antidepressants

Increase serotonin, NE, and dopamine to alleviate symptoms.