N165 Final

Limbic system

collection of brain regions that controls mood and attitude

• involved in storage of highly charged emotional memories, and controls appetite and sleep cycles

Depression

Set of neuropsychiatric disorders characterized by symptoms including a pervasive low mood, low self-esteem, changes in sleep (insomnia/hypersomnia), weight loss/gain, anhedonia, thoughts of death, fatigue & loss of energy, psychomotor agitation/retardation, feelings of worthlessness and guilt, lack of concentration, delusions/hallucinations

Anhedonia

Inability to experience pleasure or interest in formerly pleasurable or satisfying activities

Psychomotor agitation

Series of unintentional and purposeless motions that stem from mental tension and anxiety of an individual.

• includes: pacing around a room, wringing one’s hands, uncontrolled tongue movements, pulling off clothing and putting it back on…etc

Major depressive disorder (unipolar depression; clinical depression)

Having 5 or more depressive symptoms that last without remission for at least 2 weeks. Usually characterized by loss of pleasure in most or all activities, psychomotor retardation, weight loss, guilt, and insomnia

Melancholic depression

The most ‘classic’ type of depression — low mood, insomnia, loss of appetite/weight less, anhedonia

Atypical depression

Type of depression with mood reactivity (moods are overly affected by environment), paradoxical anhedonia despite apparent positivity, significant weight gain or increased appetite from comfort eating, hypersomnia (increased sleep), leaden paralysis (sensation of heaviness in limbs), and significant social impairment from hypersensitivity to perceived interpersonal rejection

Dysthymia

Less severe, but long-lasting depression that lasts for at least two years

Adjustment disorder with depressed mood

Mood disturbance appearing as a psychological response to an identifiable event or stressor or where the resulting emotional or behavioral symptoms are significant but do not meet the criteria for a major depressive episode.

Catatonic depression

Rare and severe form of major depression involving disturbances of motor behavior and other symptoms. The patient is mute, immobile or exhibits purposeless or even bizarre movements

Postpartum depression

intense, sustained and sometimes disabling depression experienced by women within three months after giving birth that can last as long as three months. Likely due to sudden withdrawal of placental hormones at birth.

• postpartum psychosis also possible

Premenstrual dysphoric disorder (PMDD)

Severe, debilitating PMS with abnormal response to normal hormone levels. Symptoms can be any combination of depression symptoms and typically start about 1 week prior to the onset of menstruation but abruptly ends when menstruation begins.

Seasonal affective disorder (SAD)

Depressive disorder related to circadian rhythms in which depressive episodes come on in autumn or winter and resolve in spring. In winter time, patients experience intense hunger, weight gain, hypersomnia, and lower mood in the evening.

Causes of depression

Biological: monoamine neurotransmitter, hormonal changes (postpartum, PMDD), circadian rhythm changes (SAD), stress responses from increased cortisol

Monoamine hypothesis

Early hypothesis about a biological basis for depression based on the observation medications that affect the monoamine neurotransmitters dopamine, norepinephrine, and serotonin may have psychological side effects affecting mood

Specific monoamine hypothesis

The theory that depression results from presynaptic / postsynaptic changes in noradrenergic (norepinephrine) or serotonergic (5-HT) pathways

Psychosocial

Positive correlation between stressful life events and onset of depression

Cognitive model

A model of depression that states that depressed patients hold pessimistic views of themselves, the world, and the future with recurrent patterns of depressive thinking, resulting in disordered information processing.

Learned hopelessness theory

A mode of depression that states that the patient loses hope that life will get better, possibly based on early life experiences, and they believe that negative experiences are due to stable, global reasons

Cognitive behavioral therapy

An empirically tested and widely used type of psychotherapy for treating depression, in which patients typically meet in groups and are taught to alter their recurrent patterns of depressive thinking so that they can restore normal information processing

Monoamine oxidase inhibitors (MAOIs)

antidepressant medication that results in a general increase in monoamine neurotransmitters (serotonin, norepinephrine, dopamine), but carries dietary risks

Tricyclic antidepressants

Antidepressant medications used to treat depression named for the three-ring chemical structure; works on serotonin and norepinephrine

Selective serotonin reuptake inhibitors (SSRIs)

An antidepressant drug that acts by blocking the reuptake of serotonin so that more serotonin is available to act on receptors in the brain

Noradrenergic serotonergic reuptake inhibitors (NSRI)

An antidepressant drug that acts similarly to SSRIs, but affects both serotonin and norepinephrine

Electroconvulsive shock therapy

Electric shock therapy used to treat severe cases of depression that have not been effectively treated by other means. Basically a grand mal seizure is induced in a sedate patient to ‘jumpstart’ or ‘reboot’ the brain. Patients will lose memory of the hours/day of the ECT and may have some fatigue

Transcranial magnetic stimulation

Depression therapy done by inducing an electrical current in the brain, but can only affect brain regions on the surface of the brain.

Deep brain stimulation (DBS)

Therapy used to treat severe depression where electrodes are implanted into the basal ganglia, as in Parkinson’s disease, and stimulate the basal ganglia at a particular frequency

Mania

Psychological state characterized by irritability, anger or rage, delusions, grandiose ideas and plans, hypersensitivity, hyper sexuality, hyper-religiosity, hyperactivity, impulsiveness, racing thoughts, pressured speech (pressure to keep talking), and a decreased need for sleep

Hypomania

Mood state characterized by persistent disinhibition and euphoric mood by generally less severe than full mania. Characteristic behaviors are being extremely energetic, talkative with a flight of creative ideas, and confident. Considered a precursor to mania, putting the subjects at great risk of harm.

Bipolar Disorder I

Episodes of severe depression alternate with mania

Bipolar disorder II

Episodes of severe depression alternate with hypomania

Cyclothymia

Dysthymia alternates with hypomania

Mixed affective disorder

Disorder characterized by combined manic and depressive symptoms, including agitation, impulsiveness, anxiety, restlessness, aggressiveness, irritability, rage, confusion, fatigue, insomnia, morbid and/or suicidal ideation, panic, paranoia, persecutory delusions, pressured speech, and racing thoughts. Experiences manic and depressive symptoms at the same time

Causes of bipolar disorder

• Genetic link & environmental disorder — possibly related to anxiety/depression spectrum disorders

• Uncontrolled changes in hormonal pathways

Hypothalamus-pituitary-adrenal axis

Major part of the neuroendocrine system that controls reactions to stress and regulates many body processes, including mood and emotions; may be abnormal in anxiety and depressive disorders

Psychotherapy for bipolar disorder

Cognitive behavioral therapy (CBT)

Medications for bipolar disorder

• mood stabilizers

• anticonvulsants

• antidepressants

• antipsychotic medication

Lithium

The element lithium is used to treat bipolar disorder together with anti-depressants. It acts as a mood stabilizer (preventing mania), but must be carefully managed because it is toxic.

Anticonvulsants (anti-seizure medications)

Generally lower neural activity

Antidepressants (e.g. SSRIs)

Only treats bipolar disorder with a mood stabilizer

Antipsychotic medication

For manic agitation, usually act to directly or indirectly lower dopamine

Anxiety

Diffuse, vague feelings of fear and apprehension; becomes a problem when it is irrational, uncontrollable, and/or disruptive

Phobia

An intense, irrational fear of a specific thing that interferes with normal behavior; may develop through classical conditioning

Anxiety disorder

A set of disorders in which the normal anxiety response is inappropriately provoked by homeostatic imbalance

Possible physiological causes of anxiety

• low levels of GABA (primary inhibitory neurotransmitter in the brain)

• Amygdala — limbic system component that controls the fear response and processes fear-related memories and stimulus salience

Treatments for anxiety

• Psychotherapy: cognitive behavioral therapy (CBT)

• Medications:

  • anti-depressants

  • anti-anxiety medications

  • beta-blockers

Anti-anxiety medications

Produce short-acting reduction in anxiety

Beta-blockers

Used to stop physical symptoms

Generalized anxiety disorder

Characterized by chronic anxiety, worry, and tension independent of external cause for at least 6 months. Patients anticipate disaster and are overly concerned about health issues, money, family problems, or difficulties at work. Physical symptoms are also often present, including headaches, stomachaches, muscle tension/trembling, irritability

• possible causes: genetics and association with childhood trauma and resulting hypervigilance

Obsessive-compulsive disorder (OCD)

An anxiety disorder most commonly characterized by obsessive, distressing, intrusive thoughts and related compulsions which attempt to neutralize the obsessions.

• symptoms: obsession and compulsion

Obsession

Irrational, disturbing thoughts that intrude into consciousness

Compulsion

Irresistible, repetitive actions performed to alleviate obsessions

Possible causes of OCD

• elevated activity in caudate nucleus (component of basal ganglia associated with initiation of learned, habitual motor activities)

• serotonin may help reduce caudate nucleus activity (why SSRIs help)

Treatment option for OCD

Deep brain stimulation

Panic disorder

A disorder characterized by recurring panic attacks (feelings of helpless terror with high physical arousal) and fear of having them

Symptoms of panic disorder

palpitations, sweating/trembling/shaking, chest pain/feeling of choking, nausea/dizziness, fear of losing control/dying

Agoraphobia

Anxiety disorder associated with panic disorder defined as a morbid fear of having a panic attack or panic-like symptoms in a situation from which it is perceived to be difficult (or embarrassing) to escape. These situations can include, but are not limited to, wide-open spaces, crowds, or uncontrolled social conditions. Sufferers of agoraphobia may avoid public / unfamiliar places

Possible causes of panic disorder

genetics & environment, initial stressful event, possible imbalance in amygdala/limbic system, possible history of stimulant use

Post-traumatic stress disorder (PTSD)

Anxiety disorder in which patients have nightmares, flashbacks, increased arousal (sleeplessness, hypervigilance), depression, irritability, and avoidance of stimuli associated with a traumatic event such as war, rape, or assault.

• complex PTSD: PTSD symptoms from extended period of mild/moderate stress

PTSD possible causes

• Alterations in baseline stress hormone levels (cortisol): initial differences in baseline cortisol levels may predispose individuals to PTSD

• Anatomical/functional differences in amygdala, hippocampus, prefrontal cortex

• Maladaptive learning pathway to fear response through a hypersensitive, hyper-reaction, hyper-responsive hypothalamus-pituitary-adrenal axis.

Phineas Gage

A railroad foreman who had a railroad rod shoot through his prefrontal cortex, resulting in drastic personality changes.

• influenced 19th-century thinking about the brain and localization of its functions

• suggested that damage to specific regions of the brain might affect personality and behavior

Lobotomy

A procedure where ice picks are placed in the orbital sockets, up into the prefrontal cortex and wiggled around, destroying tissue, in order to treat a wide variety of mental illnesses

Dorsolateral prefrontal cortex (DLPFC)

Highest cortical area responsible for motor planning, organization, and regulation, which is involved in the integration of sensory and memory information and the regulation of intellectual function and action (executive function) and is also involved in working memory.

DLPFC executive function

Cognitive tasks such as working memory, cognitive flexibility, planning, inhibition, and abstract reasoning

DLPFC working memory

Limited, active, transient traces of experiences that happened in the very recent past. RAM of human memory.

Frontal convexity syndrome

Disorder characterized by apathy, indifference, occasional outbursts, loss of self, stimulus-bound behavior, lack of planning, psychomotor retardation, motor perseveration and programming deficits, poor word list generation, poor abstraction and categorization, and working memory deficits

Perseveration of Frontal convexity syndrome

Persistent use of a specific strategy to solve a problem, despite the fact that the strategy is wrong or the rule of the task has changed

Wisconsin Card Sorting Task

Example test that can reveal the problems with executive function associated with DLPFC damage.

Anterior cingulate cortex (ACC)

Part of the cortex that subserves primarily executive functions related to emotional control and the reward system. It plays key roles in decision making, empathy, and reward anticipation, and it also is involved in autonomic functions like blood pressure and heart rate (w/ brain stem)

Medial frontal syndrome

A syndrome characterized by akinetic mutism: a paucity of spontaneous movement and gesture, sparse verbal output, lower extremity weakness and loss of sensation, and incontinence.

• Caused by: damage to medial wall of the frontal lobe, including the anterior cingulate cortex

• treatment: stimulants, L-dopa

Orbitofrontal cortex

A syndrome caused by damage to the orbitofrontal cortex that is characterized by disinhibited & impulsive behavior, inappropriate jocular affect, emotional lability, poor judgment and insight, sexual disinhibition, lack of concern for others, and distractibility

Antisocial personality disorder

• enduring pattern of inner experience that deviates from the norm of the individual’s culture.

• Condition where an adult has an enduring pattern of manipulating, exploiting, or violating the rights of others. Thought to be associated with criminal behavior in many cases

• under the umbrella of dissocial personality disorder.

Conduct disorder

Juvenile diagnosis that may turn into antisocial personality disorder in the adult.

• behaviors: bedwetting, animal abuse, pyromania, and general problems with authority.

Tourette’s syndrome

Syndrome where patients exhibit multiple motor tics and at least one vocal tic, which change over time. Typical onset is during childhood, and may be common as 1 in 100 children. 10% have coprolalia.

Frequently co-occurs with OCD, ADHD, and depression/anxiety

Motor and vocal tics

Movements or vocalizations characteristic of Tourette’s syndrome that are stereotypic, temporarily suppressible, non-rhythmic, and often preceded by an unwanted premonitory urge. Can suppress tics for a little but then have a rebound effect of more tics.

• possible treatments: behavioral approaches (habit reversal training, cognitive behavioral therapy); Deep brain stimulation; and medications

Coprolalia

Condition associated with Tourette’s syndrome in which the person has a vocal tic consisting of socially inappropriate exclamations.

Causes of Tourette’s syndrome

• genetic cause that affects frontal lobe and basal ganglia development.

• decreased size of the caudate nucleus of the basal ganglia correlated with increased severity of symptoms

• symptoms worsen with stress

Kluver-Bucy syndrome

Syndrome caused by bilateral damage to the amygdala that is characterized by placidity, diminished fear responses, inability to recognize emotional importance of an event, eating inappropriate objects, over-eating, hyper-orality, altered sexuality, visual agnosia, and hypermetamorphosis

Hypermetamorphosis

Impulse to notice and react to everything within sight

Causes of Kluver-Bucy syndrome

Thought to be caused by damage to the amygdala of the limbic system and connections between the limbic system and the frontal cortex

Treatments of Kluver-Bucy syndrome

Not very good, target symptoms and include antipsychotic meds to decrease dopamine

Schizophrenia

A disorder characterized by

• positive symptoms: hallucinations, delusions, disorganized speech and thought

• negative symptoms: absence of normal cognition or affect, flat affect, poverty of speech, and lack of motivation

• cognitive symptoms: problems with working memory and attention

Prevalence of symptoms is similar across cultures (1-2%), incidence is equal for men and women

Hallucinations

Positive symptoms. Perception in the absence of a stimulus. Perception in a conscious and awake state in the absence of external stimuli which have qualities of real perception, in that they are vivid, substantial, and located in external objective space.

Delusion

Positive symptom. Idiosyncratic, irrational belief or impression that is firmly maintained despite being contradicted by what is generally accepted as reality or rational argument, typically as a symptom of mental disorder

Disorganized speech/thought

Positive symptom.

Over-inclusion: jumping from idea to idea without the benefit of logical association

Paralogical thought: on the surface the thinking may appear logical but is actually seriously flawed.

Flat affect

Affect is a medical term for mood. A patient with a flat affect has very little reaction to events around them; they display little-to-no emotion physically, and may not feel emotions very much either

Inappropriate affect

The mood (affect) the patient displays does not match the circumstances.

Catatonic behavior (catatonia)

Unresponsiveness to environment, usually marked by immobility for extended periods and echolalia

Echolalia

Parrot-like repetition of speech

Waxy flexibility

A psychomotor symptom of catatonic schizophrenia which leads to a decreased response to stimuli and a tendency to remain in an immobile posture

Subtypes of schizophrenia

paranoid type'; disorganized type'; residual type; catatonic type; undifferentiated type

Paranoid type

Well-formed hallucinations and delusions; mostly positive symptoms / fewer negative symptoms. Most common and best prognosis

Disorganized type

Disorganized speech, silly behavior, and flat affect / disturbed emotional expression; delusions and hallucinations are less pronounced than in the paranoid type and have little meaning or logic. Patients tend to be incoherent/unintelligible and have issues with daily self-care. Also known as hebephrenic (childish behavior)

Residual type

Primarily displays negative symptoms like flat affect, reduced speech, lack of motivation

Catatonic type

unresponsive to surroundings with echolalia, waxy flexibility; rare

Undifferentiated type

Combination of hallucinations, specific delusions, and general disorganization - No single symptom type is most prominent. As with undifferentiated versions of other neuropsych disorders, these patients don’t fit well into other categories

Possible causes of schizophrenia

congenital risk; brain structure changes; neurochemical changes

Brain structure changes for schizophrenia

enlarged ventricles, decreased hippocampus and amygdala, loss of temporal and frontal cortex

• hypofrontality hypothesis: theory that problems in the frontal lobe are associated with schizophrenia

Neurochemical changes for schizophrenia

Dopamine: neurotransmitter that affects mood, energy, sexual desire and motor coordination; May play a role in schizophrenia, especially with hallucinations. Antipsychotic meds decrease dopamine

Glutamate: a key excitatory neurotransmitter. Some evidence suggests that glutamate decreases may be correlated with schizophrenia. Meds that increase glutamate, however, do not help with symptoms (that do increase the risk of seizures).

Treatments for schizophrenia

• Anti-psychotic medications: typical antipsychotic (older, more side effects), decreases dopamine brain-wide; primary effect is on positive symptoms. Atypical antipsychotics (fewer side effects) — affect dopamine pathways in more complex form and may also interact with serotonin pathways; primary effect is on positive symptoms, also some negative ones

• electroconvulsive shock therapy (catatonic schizophrenia)

• occupational therapy