CHAPTER 13 (drugs and behaviour)

Major Depressive Disorder (MDD)

A major affective (mood) disorder characterized by persistent low mood and loss of interest or pleasure.

Affective Disorders (Mood Disorders)

Disorders defined by disturbances in mood or emotion.

DSM (Diagnostic and Statistical Manual of Mental Disorders)

Authoritative handbook used to diagnose mental disorders.

DSM-5

Fifth edition of the DSM outlining diagnostic criteria for mental disorders.

Affective Symptoms

Emotional symptoms of depression (e.g., sadness).

Cognitive Symptoms

Thought-related symptoms of depression (e.g., hopelessness).

Somatic Symptoms

Physical symptoms of depression (e.g., fatigue, sleep changes).

Neuroimaging Techniques

Brain imaging methods used to identify structural and functional abnormalities.

Amygdala

Brain region involved in emotion processing; abnormal in depression.

Prefrontal Cortex (PFC)

Brain region involved in decision-making and emotional regulation; reduced activity in depression.

Hippocampus

Brain region involved in memory and stress regulation; reduced volume in depression.

Nucleus Accumbens (N. accumbens)

Brain region involved in reward processing; abnormal in depression.

Monoamine Theory of Depression

Depression results from reduced activity of monoamine neurotransmitters.

Monoamines

Neurotransmitters including serotonin, norepinephrine, and dopamine.

Serotonin (5-HT)

Monoamine neurotransmitter involved in mood regulation.

Norepinephrine (NE)

Monoamine neurotransmitter involved in arousal and mood.

Dopamine (DA)

Monoamine neurotransmitter involved in motivation and reward.

Amphetamine

Drug that enhances monoamine transmission and elevates mood.

Cocaine

Drug that enhances monoamine transmission and elevates mood.

Parkinson's Disease

Neurological disorder associated with high rates of depression.

Reserpine

Drug that depletes monoamines and can induce depression.

Vesicular Monoamine Transporter (VMAT)

Protein that transports monoamines into synaptic vesicles.

Glucocorticoid Theory of Depression

Depression is associated with chronic stress hormone dysregulation.

Hypercortisolemia

Abnormally high cortisol levels seen in depression.

Glucocorticoid Receptors

Receptors activated by cortisol that affect brain structure and function.

Hypothalamo-Pituitary-Adrenal (HPA) Axis

Stress-regulation system disrupted in depression.

Homeostasis

Stable internal physiological balance disrupted in depression.

Antidepressants

Drugs that alleviate depressive symptoms by increasing monoamine activity.

First-Generation Antidepressants

MAOIs and TCAs.

Second-Generation Antidepressants

Selective serotonin reuptake inhibitors (SSRIs).

Third-Generation Antidepressants

SNRIs and atypical antidepressants.

MAOIs

Antidepressants that inhibit monoamine oxidase.

Monoamine Oxidase (MAO)

Enzyme that breaks down monoamines.

Synaptic Vesicles

Structures that store neurotransmitters for release.

TCAs

Antidepressants that block serotonin and norepinephrine reuptake.

Reuptake

Process by which neurotransmitters are taken back into the presynaptic neuron.

Muscarinic Receptors

Acetylcholine receptors blocked by TCAs.

Histamine Receptors

Receptors involved in arousal and appetite affected by TCAs.

α1 Adrenergic Receptors

Receptors involved in blood pressure regulation affected by TCAs.

Selective Serotonin Reuptake Inhibitors (SSRIs)

Antidepressants that selectively block serotonin reuptake.

Serotonin Transporter

Protein blocked by SSRIs.

Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs)

Antidepressants that block serotonin and norepinephrine reuptake.

Atypical Antidepressants

Antidepressants with varied mechanisms of action.

Autoreceptors

Receptors that regulate neurotransmitter release via feedback inhibition.

Pharmacokinetics

Study of drug absorption, distribution, metabolism, and elimination.

Absorption

Movement of a drug from the digestive system into the bloodstream.

First-Pass Metabolism

Initial breakdown of a drug by the liver before circulation.

Blood-Brain Barrier

Barrier that antidepressants readily cross to reach the brain.

Half-Life

Time required for drug concentration to decrease by 50%.

MAOI Half-Life

2-4 hours.

TCA Half-Life

Approximately 24 hours.

SSRI/SNRI Half-Life

Approximately 15-25 hours.

Postural Hypotension

Drop in blood pressure when standing.

Cheese Effect

Dangerous reaction from tyramine ingestion while taking MAOIs.

Tyramine

Amino acid normally broken down by MAO.

Serotonin Syndrome

Potentially life-threatening condition caused by excess serotonin.

Anticholinergic Effects

Side effects due to acetylcholine blockade.

Parasympathetic Nervous System

Division of the ANS inhibited by TCAs.

Adrenergic Receptors

Receptors affecting heart rate and blood pressure.

5-HT2 Receptors

Serotonin receptors associated with SSRI side effects.

Gastrointestinal (GI) Problems

Common SSRI side effects including nausea and diarrhea.

5-HT2-3 Receptors

Serotonin receptors contributing to side effects.

Sedation

Reduced alertness caused by some antidepressants.

Tolerance

Reduced drug effectiveness over time.

Withdrawal

Symptoms occurring after abrupt discontinuation.

Akathisia

Compulsion to move, seen during withdrawal.

Insomnia

Difficulty sleeping associated with withdrawal.

Efficacy

Ability of a drug to produce therapeutic effects.

Remission

Full disappearance of depressive symptoms.

Delayed Therapeutic Onset

Delay of weeks before antidepressants show full effects.

Neuroadaptive Effects

Long-term brain changes required for antidepressant efficacy.

Treatment-Resistant Depression

Failure to respond to multiple antidepressant treatments.

Metabolism and Elimination

The section on how drugs are metabolized and eliminated from the body.