Controlled stimulants

Question 1

In general, what effects do stimulants have? (5)

Answer 1

1. Heighten mood
2. Increase alertness
3. Decrease fatigue
4. Grandiosity
5. Risk can feel more rewarding

Question 2

Controlled stimulants (4)

Answer 2

cocaine, amphetamines, Ritalin and Adderall

Question 3

Coca leaf

Answer 3

The coca leaf has mild stimulating properties when absorbed in the mouth. Used in South America- Bolivia, Ecuador, Argentina, and Peru. Indigenous populations in these regions chewed the coca leaf for its mild stimulating properties. It has religious, medical, and social uses. An individual coca leaf doesn’t contain a lot of cocaine. The content in synthetic cocaine is much higher

Question 4

Cocaine in 16th century South America

Answer 4

Spanish conquistadors arrived in South America during the 16th century, and at this time they took control over access to the coca leaf. Used the coca leaf to “pay” enslaved Incas. They believed it made them work harder and longer- since it was a stimulant. At this time- the Spanish were devout Catholics- they did not export the drug and considered it a vice. They also discouraged European use

Question 5

The coca leaf in Europe

Answer 5

In the 19th century, there were a lot of different scientific discoveries- scientists started discovering the properties of different plants. As European naturalists started to explore South America, they began to study the properties of the Coca leaf. In the 1850s, European scientists were able to isolate the active agent in coca, and they developed cocaine. Scientists began looking for therapeutic and medical uses for this drug

Question 6

Freud and cocaine

Answer 6

Freud started his career as a neurologist and was interested in neurological disorders. He has become well known for several contributions to psychology, like psychoanalysis. Many of his first writings were on therapeutic applications of cocaine- he initially thought cocaine was a miracle drug (wrote the book “On Coca”)

Question 7

“On Coca”

Answer 7

The book written by Freud. He proposed that cocaine could be used as a local anesthetic, and as a treatment for depression, indigestion, asthma, neuroses, syphilis, morphine addiction, and alcoholism. He also considered it an aphrodisiac

Question 8

The first documented addiction to cocaine

Answer 8

Ernst von Fleischl-Marxow- friend of Freud. He was a physician who investigated electrical activity of nerves and the brain. He became addicted to morphine due to chronic pain, and Freud suggested he use cocaine to treat his addiction. Cocaine only sort of worked- tolerance formed very quickly as he was taking large amounts of IV cocaine daily (1g/day). Marxow began to exhibit bizarre behavior, like paranoid delusions and formication syndrome (feeling like bugs are crawling on or under the skin).

Question 9

Cocaine use in the 1880s

Answer 9

Cocaine was widely available and part of popular culture- not a lot of taboos surrounding it. Physicians prescribed it- cocaine revolutionized surgery as an anesthetic. It was available in OTC medicines as well as in coca wine and Coca-cola. Cocaine was featured in Sherlock Holmes, and Jekyll and Hyde was written while Stevenson was using cocaine for tuberculosis. Other famous users included Thomas Edison, Jules Verne, Czar Nicholas of Russia, and President Ulysses Grant

Question 10

After the 1880s, when did beliefs regarding cocaine begin to shift?

Answer 10

By the end of the 19th century. At this point, cocaine psychosis was fairly common- erratic behavior, delusions. There were also many overdose deaths and issues with dependency. Beliefs and attitudes began to shift. In 1914, the Harrison Narcotic Act was passed it was a law to control opiates and cocaine. This led to reduction in use (for now)

Question 11

Ephedra sinica

Answer 11

A shrub that was used in traditional Chinese medicine for more than 5000 years. In 1885, Ephedrine was naturally derived from Ephedra sinica. This compound was a stimulant of the sympathetic nervous system that was used to treat asthma and was more stable than epinephrine.

Question 12

Chen and Schmidt

Answer 12

Researchers that discovered that ephedrine was highly similar to epinephrine, because it was also a stimulant of the sympathetic nervous system. It was originally used to treat asthma and was more stable than epinephrine. It is a derivative of amphetamines.

Question 13

Lazar Edeleanu

Answer 13

Romanian chemist that synthesized what is now known as amphetamine in 1887.

Question 14

Gideon Alles

Answer 14

Los Angeles chemist that discovered and published the physiological effects of amphetamines. Amphetamines are less expensive and easier to manufacture than ephedrine

Question 15

Amphetamines

Answer 15

Amphetamine, methamphetamine, and dextroamphetamine are synthetic stimulants. They had medical uses in the 1920s, but also have a high potential for abuse.

Question 16

Medical uses of amphetamines (4)

Answer 16

In the 1920s:
1. Cold and sinus problems
2. Obesity
3. Narcolepsy
4. Pep pills- give energy
Were used by soldiers on both sides of world war 2

Question 17

Symptoms of prolonged use of cocaine and amphetamines (5)

Answer 17

1. Suppress appetite
2. Prevent sleep
3. “Speed freaks”- people can go without food or sleep for multiple days
4. Formication symptoms (“speed bugs”)
5. Stimulant psychosis

Question 18

Stimulant psychosis

Answer 18

Can be caused by prolonged use of cocaine and amphetamines. Paranoid delusions and disorientation- similar to the positive symptoms of schizophrenia

Question 19

Cocaine use in the 1970s

Answer 19

In the 1970s, cocaine became a “prestige” drug- demand for the drug increased. People started to see many of the original problems that occurred in the 1880s. It was used by celebrities, pro athletes, and the wealthy

Question 20

How was cocaine typically administered in the 1970s?

Answer 20

Usually administered in small doses and intranasally. This method of administration seemed to create less problems than IV use at the time, but this wasn’t exactly an accurate belief

Question 21

Crack cocaine

Answer 21

In 1986, crack cocaine started to infiltrate neighborhoods (not the high prestige neighborhoods). It is freebased cocaine- cocaine is heated until it vaporizes. Inhaled vapors reach the brain very quickly, and has a very short delay between CS and US, increasing the potential for addiction

Question 22

Effects of crack cocaine (3)

Answer 22

1. Short duration (10-20 minutes)- high is very intense and more pleasurable than IV injection
2. The low is equally intense
3. Long term use causes paranoia, anger, anxiety/panic, deep depression, convulsions, hallucinations

Question 23

The war on drugs (1980s)- crack vs cocaine

Answer 23

“Just say no”- the movement criminalized possession rather than just drugs, making a drug user by definition a criminal. While cocaine had been considered a prestige drug in the 70s, crack was cheaper, and therefore disproportionately impacted poor neighborhoods and African American and Latino communities

Question 24

Disparities in sentencing during the war on drugs

Answer 24

In 1988, possession of 500 gs of cocaine= minimum 5 years, while possession of 5 gs of crack= minimum 5 years. This was in place until the Fair Sentencing Act in 2010

Question 25

Methamphetamine (meth)

Answer 25

Street names include ice, crystal, and crank. It was initially manufactured on the West Coast and Hawaii in the early 1990s. By 2005, labs were common on the East Coast. Although use rates are in decline, meth is still a problem in many pockets of the country

Question 26

Meth use is most prevalent with which groups?

Answer 26

Meth use is typically seen in very rural, poor areas of the country- easier to manufacture in rural areas. Also used in urban areas by gay or bi men- this is because meth is seen as a party drug and can enhance sexual prowess. However, long term meth use can also interfere with HIV prevention medications

Question 27

Complications of long term meth use (8)

Answer 27

1. Seizures/convulsions 2. Cardiovascular collapse- meth can be very toxic to the body 3. Paranoia (can be accompanied by violent behavior) 4. Deterioration of teeth due to smoking 5. Formication, skin sores due to skin picking 6. Extreme weight loss due to appetite suppression and the effects of the stimulant 7. Due to tooth decay, weight loss, and skin picking, many people undergo drastic changes in appearance even after a few months of use 8. Erectile dysfunction over the long term

Question 28

During which decade was meth considered a fad?

Answer 28

The 1990s

Question 29

What predicts which drugs a person will use?

Answer 29

Parenting matters until around age 12, and then friends predict behavior after that- the drugs your friend group are using predict what drugs a person will use.

Question 30

With stimulants, how does method of administration matter to addiction?

Answer 30

Some methods of administration allow people to experience the effects of the drug even faster and make them more at risk for addiction. Intranasal administration- effects occur within 10-15 minutes. IV injection- 30 seconds. Crack or crystal meth are smoked- onset is even faster. The US with these drugs is very intense and powerful, and the less time between the CS and US, the more likely it is that a person will develop addiction. IV and inhalation administration peaks and dies off very quickly. Snorting and oral administration have less potential for addiction- take longer to peak and longer to die off

Question 31

Duration of cocaine effects vs amphetamine effects

Answer 31

Cocaine is metabolized rapidly (20-80 minutes), while with amphetamines, the effects last 4-12 hours. The US is extreme, intense, and powerful

Question 32

Pharmacokinetics of stimulants

Answer 32

Both cocaine and amphetamines affect the monoamine neurotransmitters- they block reuptake of dopamine, norepinephrine, and serotonin. The blocking of these neurotransmitters can result in negative effects in the long term. Amphetamines also increase the release of dopamine and norepinephrine

Question 33

Monoamine neurotransmitters (4)

Answer 33

1. Norepinephrine 2. Dopamine 3. Serotonin 4. Epinephrine- did not cover this one in class

Question 34

How do the pharmacokinetics of amphetamines differ from those of cocaine?

Answer 34

Amphetamines also increase the release of dopamine and norepinephrine

Question 35

Negative impact of cocaine and amphetamines blocking the reuptake of monoamines (2)

Answer 35

1. Long term- depletion of monoamines 2. Cocaine blues- users may find that it is difficult to experience pleasure. This occurs over time with repeated use- dopamine receptors decrease

Question 36

Pharmacodynamics of cocaine in the PNS (3)

Answer 36

1. Powerful local anesthetic-no longer used for surgery but derivatives are used 2. Causes inhibition and numbness to local nerves 3. Vasoconstrictor- causes an incision to bleed less

Question 37

Pharmacodynamics of cocaine in the CNS (4)

Answer 37

1. Powerful psychostimulant 2. Highly reinforcing 3. Increases synaptic action of dopamine, norepinephrine, and serotonin 4. Blocks reuptake, also acts as an agonist at the receptor- can change amount of neurotransmitter released

Question 38

Both cocaine and amphetamines hijack the

Answer 38

Mesolimbic dopaminergic pathway- they chemically activate the reward system

Question 39

How does cocaine act at the synapse?

Answer 39

Cocaine blocks transporter reuptake of the monoamines. When there are more monoamines, the NTs keep binding to the receptors and stimulate the reward mechanisms

Question 40

Pharmacodynamics of amphetamines

Answer 40

This category of drugs has 3 different mechanisms at the synapse: 1. Blocks and reverses transporter reuptake of monoamines 2. Blocks enzymes that degrade monoamines 3. Blocks transporter that fills vesicles with monoamines This results in a lot more neurotransmitters in the synaptic cleft for a longer period of time

Question 41

Stimulants

Answer 41

Sympathomimetic drugs- mimic activity of the sympathetic nervous system. The physiological effects of many stimulants are very similar at low-moderate doses

Question 42

Stimulants cause an increase in

Answer 42

Heart rate, blood pressure, respiration, blood flow to large muscle groups and brain- can put intense strain on the cardiovascular system over time.

Question 43

Anorectic effects of stimulants

Answer 43

Suppression of appetite- this is one of the reasons that these drugs were prescribed for weight loss. Didn’t work in the long term due to tolerance

Question 44

Behavioral effects of stimulants (3)

Answer 44

1. Feelings of elation, increased talkativeness, alertness and arousal 2. Insomnia 3. Increases confidence and decreases inhibition.

Question 45

Why aren't cocaine and amphetamines good study drugs?

Answer 45

These stimulants increase confidence and decrease inhibition. However, they don't increase advanced problem solving or reasoning. They give you the energy to quickly write a 10 page paper, but the paper won't necessarily be good. People have trouble differentiating between good and bad decisions

Question 46

Effects of stimulants on physical performance

Answer 46

Stimulants enhance physical performance on a variety of tasks. They enhance physical endurance and cause an increase in strength. These drugs also increase resistance to boredom and fatigue, which is why stimulants are sometimes used as study drugs

Question 47

How do stimulants impact cognitive performance?

Answer 47

Speed up performance on several cognitive tasks. However, there is a speed-accuracy trade off. You may answer a question more quickly and confidently, but that doesn’t mean you’re more likely to answer accurately. Seems to impair ability to learn complex concepts

Question 48

Effects of stimulants at low-moderate doses (6)

Answer 48

1. Increase in heart rate, blood pressure, respiration, blood flow- mimics activation of SNS 2. Anorectic effects 3. Elation, talkativeness, enhanced alertness, confidence and arousal 4. Physical endurance, enhanced strength, resistance to boredom and fatigue 5. Speeds up cognitive performance 6. Sexual prowess- increase desire in some users but results in decreased performance

Question 49

Acute effects of stimulants at high doses (2)

Answer 49

1. Psychotic states 2. Significantly increased risk of overdose

Question 50

Stimulant induced psychosis

Answer 50

Paranoid delusions are the most common symptom. People also exhibit compulsive stereotyped behavior- rocking, hair pulling, chain smoking, fidgeting with things. Stimulant induced psychosis can be treated with antipsychotics

Question 51

Symptoms of stimulant overdose

Answer 51

convulsions, seizures, respiratory collapse, heart attack

Question 52

Prenatal exposure to stimulants- history

Answer 52

Used to create a public sense of hysteria- the idea that a population of people will grow up experiencing deficits from crack. Not good to expose babies to stimulants and there are still many risks, but this epidemic of issues still did not materialize

Question 53

Women to take stimulants while pregnant are at risk for (3)

Answer 53

Higher risk of- fetal death, miscarriage, premature labor

Question 54

Effects on children whose mothers took stimulants while pregnant

Answer 54

Lower birth weight, abnormal arousal, seizures, enhanced startle response- this startle response is also observed in children whose mothers smoked tobacco. All seem to be short lived when controlling for other maternal factors. Intellectual deficits seem to endure- attributed to the environment, primarily. The prenatal environment continues postnatally since the stressors experienced during pregnancy generally continues. These children did not have an increased risk of addiction in the future. Trimester, amount, and duration of use matters

Question 55

Inattentive symptoms of ADHD (5)

Answer 55

1. Careless mistakes 2. Difficulty focusing 3. Forgetfulness/losing things 4. Difficulty staying on task/following instructions 5. Organization problems

Question 56

Hyperactive symptoms of ADHD (6)

Answer 56

1. Fidgeting/restlessness/trouble sitting still 2. Trouble stopping themselves from X (calling out an answer, interrupting) 3. Excessive talking/movement 4. Acting without thinking 5. Trouble waiting in line/for your turn 6. Reduced inhibition to risk

Question 57

3 presentations of ADHD

Answer 57

1. Primarily inattentive 2. Primarily hyperactive- usually diagnosed in young boys 3. Combined type

Question 58

Diagnosis of ADHD

Answer 58

For an ADHD diagnosis, at least 6 symptoms have to be present for 6 months. These behaviors are not age appropriate and impair normal functioning. They also cannot be the result of other problems. There is a lot of variation in terms of what normal ADHD looks like

Question 59

Prevalence rates of ADHD

Answer 59

Among ages 3-17, 6-16%

Question 60

How many people with ADHD take a stimulant medication?

Answer 60

38-81% are taking a stimulant medication- medication is usually not recommended for children younger than 6. Behavioral interventions (for the individual and the family) should accompany medication

Question 61

People with ADHD are more likely to have problems with (6)

Answer 61

1. Accidents and injuries 2. Job loss and divorce 3. Higher risk of addiction/substance use disorders 4. Emotional regulation 5. Sense of time/timing 6. Excessive risk taking behavior

Question 62

Why does ADHD need to be treated?

Answer 62

People with ADHD make up a large proportion of the population. They may have issues with work, school, or relationships, and are more likely to be affected by accidents or injuries. More likely to have issues with substance use, especially stimulants- might be self medicating

Question 63

Conduct disorder

Answer 63

Lack of empathy, aggression, emotional outbursts- stimulants might not be recommended for this group, SSRIs can be used instead

Question 64

Comorbidity of ADHD

Answer 64

64% of these individuals meet the criteria for another disorder. Other co-occurring disorders include behavior or conduct disorders, anxiety, depression, autism spectrum disorder, and Tourette syndrome

Question 65

Current treatment model for ADHD

Answer 65

Multimodal treatment-medication helps to manage symptoms. Behavioral therapy also helps manage day to day tasks. It includes skills and strategies to minimize impairment and social skills training

Question 66

Chemical differences in ADHD brains

Answer 66

lower levels of dopamine and norepinephrine

Question 67

In ADHD, structural differences are observed in (3)

Answer 67

1. Prefrontal cortex 2. Basal ganglia 3. Cerebellum

Question 68

Prefrontal cortex function

Answer 68

inhibition, self regulation, planning, working memory

Question 69

Basal ganglia function

Answer 69

learning, reinforcement, punishment, motivated responding, learning associations between ideas

Question 70

Cerebellum function

Answer 70

involved in timing, coordination. A network between the PFC and cerebellum regulates other systems

Question 71

ADHD structural differences in the prefrontal cortex

Answer 71

The prefrontal cortex matures at a slower pace in ADHD. It takes 7.5 years in neurotypical brains, but 10.5 years in ADHD brains. MRIs show decreased prefrontal-limbic blood flow. There is also a pattern of disrupted activity and connectivity

Question 72

Roles of the PFC in working memory (3)

Answer 72

1. Manipulating information in your mind 2. Regulating attention, organization, planning 3. Self monitor and changing behavior

Question 73

How are ADHD brains physically different from neurotypical brains?

Answer 73

ADHD brains have overall delayed brain growth relative to neurotypical brains. They have a smaller right prefrontal cortex and cerebellum. There are also abnormalities in the basal ganglia related to reward and learning.

Question 74

Abnormalities in the basal ganglia in ADHD

Answer 74

The caudate nucleus and globus pallidus are smaller. The basal ganglia contains a high density of dopamine receptors, so these abnormalities affect reward and learning

Question 75

What is the frontostriatal circuit?

Answer 75

Includes the ventral and dorsal anterior cingulate, which control affective and cognitive components of executive control. Also includes portions of the basal ganglia and the nucleus accumbens

Question 76

Abnormalities in the frontostriatal circuit in ADHD

Answer 76

In ADHD there are abnormalities in the frontostriatal circuits which extend to the amygdala and cerebellum.

Question 77

Fronto-cerebellar circuit

Answer 77

This circuit is involved in temporal processing. It includes the prefrontal cortex, basal ganglia, and cerebellum. These brain regions are closely connected in cognition and learning. In ADHD, there may be reduced connectivity between the PFC and cerebellum, resulting in a variety of symptoms depending on the region that is impacted. Fronto-cerebellar circuit abnormalities might represent a distinct subtype of ADHD

Question 78

Delayed PFC growth causes

Answer 78

Problems with executive functioning- like attending to irrelevant information or stopping yourself from doing something

Question 79

Problems with the basal ganglia causes

Answer 79

Issues with delaying reward

Question 80

Cerebellum dysfunction is associated with

Answer 80

Difficulty predicting when events are likely to occur, problems with timing, and circadian dysfunction.

Question 81

In the PFC and BG, symptoms of ADHD are linked with which neurotransmitters?

Answer 81

Dopamine and norepinephrine. These neurotransmitters are linked to reward and pleasure. When a person is anticipating a pleasurable event, like the end of class, dopamine increases.

Question 82

Delayed reinforcement gradient

Answer 82

Change in learning due to delay between key stimuli or responses, and reinforcement. Reinforcement is most effective when it is immediate, so this delay makes it less effective. In ADHD, a reinforcer loses its value quickly, which makes it difficult to change behavior. Only short sequences of responses can be reinforced due to the short critical window in which behavior can be reinforced. Children tend to respond better to immediate rewards over delayed rewards and only show learning when rewards are received immediately and frequently.

Question 83

Dynamic developmental theory of ADHD

Answer 83

Hypothesizes that there is a dysfunction of dopamine transmission in the frontal-limbic circuits. This dysfunction is responsible for a steeper delay of reinforcement gradient due to lower tonic (baseline) levels of dopamine. This model proposes that due to the steep delay of reinforcement, there is a critical window during which reinforcement of behavior can occur in individuals with ADHD.

Question 84

Tonic vs phasic phase

Answer 84

Tonic phase is the baseline state of the levels of a hormone or neurochemical. Phasic phase occurs during a stressful event

Question 85

Reinforcement in the brain of someone with ADHD

Answer 85

Due to the delayed reinforcement gradient, immediate reinforcement is very rewarding, and delayed reinforcement is very weak. This causes problems for people with ADHD, because our society tends to reward delayed gratification.

Question 86

Psychostimulants in ADHD

Answer 86

Psychostimulants are first line treatment for ADHD (tried first) and are used in combination with therapy. Includes Adderall and Ritalin- they both inhibit dopamine reuptake

Question 87

Psychostimulant mechanisms (3)

Answer 87

1. Inhibit dopamine reuptake 2. Upregulate dopamine and norepinephrine activity 3. Increase PFC activity and down regulate some BG activity

Question 88

Optimal response curve

Answer 88

The prefrontal cortex requires a proper level of catecholamines (dopamine and norepinephrine) for optimal function. When the dopamine/NE level is too low, people can experience drowsiness and ADHD symptoms, like distraction and poor impulse control. When the dopamine level is too high due to an excessive dose of the stimulant, people can experience stress, elevated arousal, and hyperfixation on irrelevant stimuli. The optimal response curve depicts the amount of the stimulant that allows the person to be optimally treated- focused, organized, and flexible

Question 89

Ritalin

Answer 89

Generic name is methylphenidate. Ritalin is fast acting and peaks 2 hours after administration. It inhibits the reuptake of dopamine and norepinephrine and therefore increases its concentration in the CNS.

Question 90

Adderall

Answer 90

Generic name is amphetamine. It is longer acting and peaks 3-7 hours after administration. It increases norepinephrine and dopamine in CNS by multiple mechanisms

Question 91

Adderall mechanisms (4)

Answer 91

1. Blocks reuptake 2. Inhibits auto receptors 3. Increase NT release 4. Increase number of postsynaptic receptors

Question 92

What happens if someone with a neurotypical brain takes ADHD drugs?

Answer 92

People with ADHD have underaroused brains, and stimulants may help with increasing arousal. The symptoms of ADHD may be due to seeking new stimuli to stimulate their brain- looks like hyperactivity and inattention on the outside. Since there’s less dopamine between the neurons, you need a bigger response to get it flowing. Using these drugs in neurotypical brains pushes someone to a bad spot in the optimal response curve

Question 93

How are ADHD drugs different from cocaine or methamphetamine?

Answer 93

Administration differs substantially- using illicit drugs is much more risky than using a prescribed drug to treat a problem. Cocaine and methamphetamine are typically taken in increasing doses over time. They are used recreationally and people can develop tolerance. The methods of administration are different- the illicit drugs are inhaled, injected, or snorted. Also, illicit drugs are often mixed with other things and you can’t be sure you’re getting a precise dose

Question 94

Administration of ADHD medications (4)

Answer 94

1. Typically taken in measured and precise doses, which are monitored and updated as needed 2. Use is instrumental and specific (1 tablet in the AM and after lunch) 3. Via transdermal patch, oral administration, extended release 4. Peak is not as high and occurs over longer periods of time- reduces craving and withdrawal

Question 95

Benefits of ADHD drugs (6)

Answer 95

There is a strong base of evidence for the effectiveness of these drugs. 1. Increased academic achievement 2. Decreased absenteeism at school- teaches tend to respond to the kids better and removes some stigma in the classroom 3. Reduced risk of emergency administration at the hospital for injury/trauma 4. Lower risk of depression and anxiety 5. Decreased substance abuse 6. Measurable and significant benefits in children, adolescents, and adults

Question 96

Adverse effects of stimulant medications with proper use (6)

Answer 96

1. Decreased appetite- slower physical growth in children 2. Sleep disturbances- trouble falling asleep or trouble with deep sleep- can be helped with a careful dosing schedule 3. Stomach aches 4. Drowsiness 5. Increased emotionality 6. Increased blood pressure and pulse

Question 97

Monitoring while on ADHD medication

Answer 97

Children and adolescents are monitored carefully while on medication- height and weight compared to peers, blood pressure and heart rate monitored regularly, prescreen children for other risk factors prior to medication. Some kids also have treatment interruptions/medication holidays. There is not a significant association between these drugs and cardiovascular events

Question 98

Which group of people is more likely to abuse ADHD drugs?

Answer 98

People with comorbidities (like conduct disorder) are more likely to abuse the stimulants or distribute them to friends

Question 99

Do ADHD drugs increase risk of addiction?

Answer 99

No. There is a significantly reduced risk of SUD when people with ADHD are given proper medical treatment. When people have their ADHD treated, there is also a reduction in self medicating behaviors