Adrenaline - the neurotransmitter also known as epinephrine, released by the
adrenal glands to activate bodily systems as part of the fight-flight response.
Adrenocorticotrophic hormone (ACTH) – a substance released by the pituitary
gland that travels to the adrenal glands, causing the release of cortisol.
Afferent nerves – nerves that send sensory information from sensory receptors to
the central nervous system.
Amygdala – an almond-shaped structure in the limbic system that helps regulate
rage, aggression and sexual behavior as well as feelings of affection and is
believed to be involved in depression.
Antidepressants – prescription medications that can be effective in reducing
symptoms of depression.
Asylum – facility common in the past where the mentally ill were kept in
isolation and received limited care.
Autonomic nervous system – network of nerves from the central nervous system to
the internal organs that controls involuntary responses such as heart rate,
blood pressure, digestion, and breathing.
Axon – projection at opposite end of the neuron from dendrites; sends
information in the form of neurotransmitter substances to another nerve cell.
Biogenic – caused by biological factors.
Bi-directional causation – concept that biological processes (such as those of
the brain, immune system or genes) and behavior and mental processes mutually
influence each other.
Bipolar disorder – a type of mood disorder once called manic-depression, in
which an individual alternates between periods of extreme depression and mania.
Body humors – substances once believed to exist in the body, imbalances of which
were believed to cause disease, including mental disorders.
Cartesian (mind-body) dualism – Rene Descartes’ concept that there are two types
of elements: 1) physical matter, which is in the realm of science and can be
measured by scientists, and 2) spiritual or mental matter, which has no physical
properties and can not be measured by science, but is the domain of religion and
Central nervous system – portion of the nervous system comprised of the brain,
spinal cord and brain stem, which is the lower extension of the brain,
connecting it to the spinal cord.
Cerebellum – located in the hindbrain, it plays a vital role in muscle
coordination, motor behavior and integration of movement, as well as non-motor
functions such as speech, learning, emotions, and attention.
Cerebral cortex – (also known as “neocortex” or “cortex”) the deeply wrinkled
outermost layer of the brain; involved in higher mental processes such as
reasoning, planning, memory, and speech – that is, thinking in general.
Chemical imbalance – a predominant neurobiological theory that an excess or
deficit of specific neurotransmitters causes, or is strongly linked to, mental
Cingulate cortex – brain structure and part of the limbic system that affects
awareness of mood state and is believed to play a role in depression.
Cognitive-behavioral therapy (CBT) – a type of psychotherapy that helps a person
recognize and change negative styles of thinking and behaving that are often
associated with mental or emotional dysfunction.
Cognitive distortions – pessimistic and unrealistic ways of thinking about
oneself, others, the future and the world that, if habitual, can contribute to
mental or emotional dysfunction.
Co-morbidity – having more than one illness at the same time.
Corpus callosum – band of tissue between the left and right hemispheres of the
brain that acts as a conduit for, and integrator of, information between the two
sides of the brain.
Corticotrophin releasing factor (CRF) – a hormone released by the hypothalamus
that stimulates the pituitary gland to release corticotrophin as part of the HPA
Cortisol – a long-acting stress hormone, which at moderate levels (when the HPA
axis is functioning normally) facilitates a variety of bodily processes, but in
excess can be damaging and put one at risk of stress and depression.
Course –progression of a disease over time with respect to severity and
Dendrite – projection at one end of the neuron that accepts incoming information
in the form of neurotransmitter substances from an adjacent nerve cell.
Diaphragm – muscle tissue in the lower abdomen that is essential to breathing.
Diaphragmatic breathing – type of breathing that involves the conscious use of
the diaphragm to produce deep, efficient breathing associated with a calm,
Diathesis-stress model of illness – theory that the interaction of stress and an
inherited vulnerability to a particular type of disease causes illness (stress +
genetic/biological vulnerability = illness).
Discrimination – the act of making a difference in treatment or favor on a basis
other than individual merit.
Distress – experiencing more stress than we can effectively cope with.
Dysthymia – a type of depressive disorder that is milder than major depressive
disorder, but is chronic – lasting at least two years for adults and one year
for children and adolescents.
Efferent nerves – nerves that send impulses from the brain to direct voluntary
activity of the muscles.
Electroconvulsive therapy/shock therapy (ECT) – a form of treatment for
depression in which mild electrical stimulation is applied to the brain;
considered a safe, accepted form of treatment, especially for severe depression
that does not respond to other treatment strategies.
Eustress – effort without distress; having the capacity to cope.
Exorcism – a religious ritual whose purpose is removal of an evil spirit
believed to be inhabiting a person’s body and causing mental illness.
Experimental method – An approach used in research, in which a hypothesis is
tested under controlled conditions to determine a relationship (possibly causal)
between two or more variables.
Fight-flight response – an automatic physiological reaction to danger that
involves activation of some bodily systems via the sympathetic nervous system.
Forebrain – a number of brain structures, including the cerebral cortex,
involved with higher mental functions as well as some of the more animalistic
ones, such as the “fight-flight” response, aggression, eating, and sex.
Frontal lobe – located at the front of the neo-cortex behind the forehead, this
major division of the cortex deals with the most advanced human functions. The
most forward segments, the prefrontal lobes, are associated with complex thought
processes, such as planning, anticipation, judgment, problem solving and
inhibition of impulses.
Gyri – folds or ridges on the outermost layer of the cerebral cortex.
Herbal treatments – non-FDA approved, but legally available, preparations
derived from plants that are sometimes used as alternatives to pharmaceutical
drugs for the treatment depression or other types of emotional problems.
Hindbrain – located about where the spinal cord comes into the brain, this
region is considered the most primitive part of the brain; it is responsible for
most bodily functions that maintain life.
Hippocampus – a brain structure located in the limbic system that is critical to
memory, learning and emotions and seems to have a role in helping “cement” some
memories into place for events with strong emotional meaning; it is reduced in
size in some individuals who are depressed.
Homeostasis – the state in which all systems in the body are functioning
normally and smoothly, and there is no net loss of energy or ability to cope.
Hypothalamic-pituitary-adrenal (HPA) axis – a process that is part of the body’s
stress response, involving the hypothalamus and the pituitary and adrenal glands
in a feedback loop; when this system is impaired, depression can result.
Hypothalamus – brain structure that serves as the integration center of the
autonomic nervous system, regulating hormones, appetite, sleep, libido (sexual
interest), the fight-flight response, and the capacity to experience pleasure,
and is believed to play a role in depression.
Inhibitory and excitatory impulses – two types of messages sent by neurons via
neurotransmitters; inhibitory impulses lower the chance that the receiving
neuron will reach a critical threshold and fire, whereas excitatory impulses
move the neuron toward its critical level for firing.
Integrative model – concept of illness as a product of complex interactions
among multiple factors (biological, neurological, genetic, environmental,
cultural, and social).
Interpersonal therapy (IPT) – a type of psychotherapy that helps a person
improve unhealthy personal relationships that may cause, worsen or contribute to
a mental or emotional dysfunction.
Left hemisphere – left side of the brain, mainly involved in sequential thinking
(processes information primarily in analytical and logical ways) and verbal
Limbic system – region deep within the brain that includes the hypothalamus,
hippocampus, and amygdala and plays an important role in emotional, sexual, and
survival functions. It has many connections to the cerebral cortex and to the
endocrine and autonomic systems.
Locus coeruleus – part of the brain stem that is a site for the manufacture of
Major depressive disorder – a severe type of depressive disorder, often
recurrent, characterized by at least two weeks of persistent sad mood, loss of
interest in activities or pleasure, and at least four other symptoms of
Mania – an extreme in mood, the opposite of depression, characterized by highly
energetic, driven behavior and thinking, with possible symptoms including
grandiose expectations, little need for sleep, and involvement in high-risk
Medulla – part of the hindbrain where the spinal cord joins the brain stem;
helps regulate basic functions such as heartbeat and respiration.
Meninges – membranes that encase the brain, providing protection.
Midbrain – area of the brain that serves as the relay center between the
hindbrain and the forebrain, sending stimuli to higher brain centers.
Monoamines – a type of neurotransmitter made from amino acids, a basic element
Mood disorder – a type of mental disorder characterized by disturbance of normal
mood (feeling), such as depression.
Myelin – a covering around the axons of the neurons that facilitates
transmission of nerve impulses.
Nature-nurture – refers to a long-standing philosophical debate over whether the
causes of behavior or mental illness are primarily biological (genetics, brain
injury, or medical conditions) or environmental (learning acquired by a person’s
experiences through the exercise of free will in his or her physical, social and
Neuron – nerve cell, the basic building block of the nervous system, which
communicates through neurotransmitter exchanges.
Neurotransmitter – chemical substance in the nervous system that is exchanged by
neurons, transmitting information within the brain and from the brain to the
rest of the body.
Norepinephrine – a monoamine neurotransmitter that appears to play a role in
regulation of mood, released from the adrenal gland.
Occipital lobe – at the back of the brain, this major division of the cortex
processes visual sensations of all kinds, including colors and shapes.
Outcome –the effects of a disease at the end of its course (possible outcomes:
complete recovery, impaired function, or death).
Parasympathetic nervous system – maintains the body at homeostasis (moves it
from the “fight or flight” mode back to the “maintenance” mode).
Parietal lobe – located at about midpoint in the top of the brain, this major
division of the cortex processes sensory input and has a critical role in verbal
and spatial reasoning and musical sound recognition.
Peripheral nervous system – all nerves and neurons in the body other than those
in the brain, brain stem, and spinal cord.
Pons – part of the hindbrain where the spinal cord joins the brain stem; helps
regulate basic functions such as heartbeat and respiration.
Postpartum depression – a type of mood disorder similar to major depression that
sometimes occurs in women following childbirth.
Prefrontal area – brain structure and most forward part of the frontal lobe of
the cerebral cortex; helps with regulation of emotions and is believed to play a
role in depression.
Prevalence – the frequency of occurrence of a disorder in a population.
Pruning – a natural process that causes neural circuits to wither away and die
from lack of use, especially important during the early stages of neural
development, particularly during the first two years of life.
Psychogenic – caused by psychological factors.
Psychotic/psychosis – relates to mental disorders in which a person becomes
incapable of distinguishing between reality and non-reality; examples include
delusions (beliefs that are demonstrably unreal, such as that one is being
plotted against by the world) or hallucinations.
Psychotherapy – also known as “talk therapy,” the treatment of mental disorders
or other psychological problems by counseling.
Raphe nucleus – part of the brain stem that produces serotonin.
Receptors/receptor site – point on a cell wall that receives neurotransmitter
molecules from adjacent cells.
Reticular activating system (RAS) – network of neurons mostly within the
brainstem that helps regulate attention and arousal levels (sleep and
Reuptake – process by which the reuptake pump removes neurotransmitter molecules
from the synaptic cleft, returning them to the neuron.
Reuptake pump – a structure in the neuron that removes neurotransmitter
molecules from the synaptic cleft.
Right hemisphere – right side of the brain, primarily involved with nonverbal
(e.g. spatial, visual, mechanical, emotional) mental functions; simultaneously
processes multiple types of stimuli in a holistic, intuitive way.
Risk factors – variables associated with a higher risk of developing a disorder.
Seasonal affective disorder – a type of depression that results from reduced
exposure to sunlight during the fall and winter.
Selective serotonin reuptake inhibitors (SSRIs) – newer antidepressant
medications that are thought to work by decreasing reuptake of serotonin, making
more available for neurotransmission.
Sensory cortex – an area in the parietal lobe that controls perception of touch
and pressure and fine discriminations such as judgment of texture and size.
Somatic nervous system – the part of the nervous system involved in sensory and
motor functions; its neurons conduct impulses back and forth between the central
nervous system and the rest of the body.
Stereotype – simplistic and biased portrayal of a cultural group, such as the
mentally ill, often arising from ignorance or fear.
Stigma/stigmatization – unwarranted negative attitudes about or behaviors toward
persons with particular characteristics, in this case, mental illness.
St. John’s Wort – a type of plant and herbal treatment widely used to treat
depression, although recent research has found it to be ineffective for this
Stress – the responses of a person to any demands that are sufficient to disturb
homeostasis; the stress response tries to keep one’s systems in homeostasis.
Stressor – any event that requires us to change or adapt.
Sympathetic nervous system – system that controls the body’s survival mode, also
known as the “fight or flight” response, by regulating internal organs under
conditions of high stress.
Substance-induced mood disorder – a type of mood disorder caused by exposure to
a substance, such as an environmental toxin, medication or illicit drug.
Sulci - fissure on the outermost layer of the cerebral cortex.
Synapse – junction between two adjacent nerves, where the activity of one cell
Synaptic cleft – narrow gap between adjoining cells, where neurotransmitters
flow from one cell to another.
Synaptic plasticity – the brain’s capacity to establish or strengthen neural
connections from repeated use, increasing the likelihood that a particular
pathway will be used again.
Synaptic vesicle – structure that transports neurotransmitters from point of
manufacture to the terminal buttons from which they are released into the
Temporal lobes – located on each side of the head at about ear level, this major
division of the cortex processes language and auditory and olfactory input; also
play a role in sorting of information, believed to be an important aspect of
Terminal buttons – located on the ends of axons, these sites release
neurotransmitters into the synaptic cleft to be picked up by a receptor site on
an adjacent neuron.
Thalamus – structure within the forebrain that relays and integrates information
sent to the cerebral cortex from other parts of the brain.
Transcranial magnetic stimulation (TMS) – a promising but still experimental
treatment for depression using a high-intensity magnetic field briefly applied
to the scalp to alter neuronal function in the area of the brain beneath.
Trephining – a process used several thousand years ago, when mental illness was
believed to be caused by evil spirits, in which holes were drilled in the skull
of a person to allow the “evil spirit” to leave the body.
Tricyclic antidepressants (TCAs) – some of the first antidepressant medications,
which worked by affecting activities of the monoamine neurotransmitters
serotonin and norepinephrine.
Visual imagery – a stress-relaxation technique that involves imagining a calming
scene, building in many details, to make it seem real.
Yerkes response curve – an inverted U-shaped curve that graphically represents
the relationship between varying stress levels and performance. If stress is
low, performance improves with an increase in stress, but at very high levels of
stress, the effect is reversed, resulting in declining performance.