Signs and symptoms include:

- Drug seeking behavior

- Multiple prescriptions from different providers

- Increased use over time

- Opioid cravings

- Multiple medical complications from drug use (HIV/AIDS, hospitalizations, abscesses)

- Legal or social ramifications secondary to drug use

- Withdrawal symptoms

Signs and symptoms of opioid intoxication include:

- Decreased perception of pain

- Euphoria

- Confusion

- Desire to sleep

- Nausea

- Constipation

- Miosis

The signs and symptoms of benzodiazepine dependence include feeling unable to cope without the drug, unsuccessful

attempts to cut down or stop benzodiazepine use, tolerance to the effects of benzodiazepines, and withdrawal symptoms when not taking the drug. Some withdrawal symptoms that may appear include anxiety, depressed mood, depersonalisation, derealisation, sleep disturbance, hypersensitivity to touch and pain, tremor, shakiness, muscular aches, pains, twitches, and headache. Benzodiazepine dependence and withdrawal have been associated with suicide and self-harming behaviors, especially in young people. The Department of Health substance misuse guidelines recommend monitoring for mood disorder in those dependent on or withdrawing from benzodiazepines.

Benzodiazepine dependence is a frequent complication for those prescribed for or using for longer than four weeks, with physical dependence and withdrawal symptoms being the most common problem, but also occasionally drug-seeking behavior. Withdrawal symptoms include anxiety, perceptual disturbances, distortion of all the senses, dysphoria, and, in rare cases, psychosis and epileptic seizures.

Cannabis withdrawal symptoms can occur in one half of patients in treatment for cannabis use disorders. These symptoms include dysphoria (anxiety, irritability, depression, restlessness), disturbed sleep, gastrointestinal symptoms, and decreased appetite. Most symptoms begin during the first week of abstinence and resolve after a few weeks.

According to the National Cannabis Prevention and Information Centre in Australia, a sign of cannabis dependence is that an individual spends noticeably more time than the average recreational user recovering from the use of or obtaining cannabis. For some, using cannabis becomes a substantial and disruptive part of an individual's life and he or she may exhibit difficulties in meeting personal obligations or participating in important life activities, preferring to use cannabis instead. People who are cannabis dependent have the inability to stop or decrease using cannabis on their own.

Benzodiazepine dependence is the condition resulting from repeated use of benzodiazepine drugs. It can include both a physical dependence as well as a psychological dependence and is typified by a withdrawal syndrome upon a fall in blood plasma levels of benzodiazepines, e.g., during dose reduction or abrupt withdrawal.

Cannabis use is associated with comorbid mental health problems, such as mood and anxiety disorders, and discontinuing cannabis use is difficult for some users. Psychiatric comorbidities are often present in dependent cannabis users including a range of personality disorders.

Physical dependence can manifest itself in the appearance of both physical and psychological symptoms which are caused by physiological adaptions in the central nervous system and the brain due to chronic exposure to a substance. Symptoms which may be experienced during withdrawal or reduction in dosage include increased heart rate and/or blood pressure, sweating, and tremors. More serious withdrawal symptoms such as confusion, seizures, and visual hallucinations indicate a serious emergency and the need for immediate medical care. Sedative hypnotic drugs such as alcohol, benzodiazepines, and barbiturates are the only commonly available substances that can be fatal in withdrawal due to their propensity to induce withdrawal convulsions. Abrupt withdrawal from other drugs, such as opioids can cause an extremely physiologically and psychologically painful withdrawal that is very rarely fatal in patients of general good health and with medical treatment, but is more often fatal in patients with weakened cardiovascular systems; toxicity is generally caused by the often-extreme increases in heart rate and blood pressure (which can be treated with clonidine), or due to arrhythmia due to electrolyte imbalance caused by the inability to eat, and constant diarrhea and vomiting (which can be treated with loperamide and ondansetron respectively) associated with acute opioid withdrawal, especially in longer-acting substances where the diarrhea and emesis can continue unabated for weeks, although life-threatening complications are extremely rare, and nearly non-existent with proper medical management.

Include the following:

- Depression

- Shaking

- Feeling unreal

- Appetite loss

- Muscle twitching

- Memory loss

- Motor impairment

- Nausea

- Muscle pains

- Dizziness

- Apparent movement of still objects

- Feeling faint

- Noise sensitivity

- Light sensitivity

- Peculiar taste

- Pins and needles

- Touch sensitivity

- Sore eyes

- Hallucinations

- Smell sensitivity

All sedative-hypnotics, e.g. alcohol, barbiturates, benzodiazepines and the nonbenzodiazepine Z-drugs have a similar mechanism of action, working on the GABA receptor complex and are cross tolerant with each other and also have abuse potential. Use of prescription sedative-hypnotics; for example the nonbenzodiazepine Z-drugs often leads to a relapse back into substance misuse with one author stating this occurs in over a quarter of those who have achieved abstinence.

Sedative-hypnotics such as alcohol, benzodiazepines, and the barbiturates are known for the severe physical dependence that they are capable of inducing which can result in severe withdrawal effects. This severe neuroadaptation is even more profound in high dose drug users and misusers. A high degree of tolerance often occurs in chronic benzodiazepine abusers due to the typically high doses they consume which can lead to a severe benzodiazepine dependence. The benzodiazepine withdrawal syndrome seen in chronic high dose benzodiazepine abusers is similar to that seen in therapeutic low dose users but of a more severe nature. Extreme antisocial behaviors in obtaining continued supplies and severe drug-seeking behavior when withdrawals occur. The severity of the benzodiazepine withdrawal syndrome has been described by one benzodiazepine drug misuser who stated that I'd rather withdraw off heroin any day. If I was withdrawing from benzos you could offer me a gram of heroin or just 20mg of diazepam and I'd take the diazepam every time – I've never been so frightened in my life. Those who use benzodiazepines intermittently are less likely to develop a dependence and withdrawal symptoms upon dose reduction or cessation of benzodiazepines than those who use benzodiazepines on a daily basis.

Misuse of benzodiazepines is widespread amongst drug misusers; however, many of these people will not require withdrawal management as their use is often restricted to binges or occasional misuse. Benzodiazepine dependence when it occurs requires withdrawal treatment. There is little evidence of benefit from long-term substitution therapy of benzodiazepines, and conversely, there is growing evidence of the harm of long-term use of benzodiazepines, especially higher doses. Therefore, gradual reduction is recommended, titrated against withdrawal symptoms. For withdrawal purposes, stabilisation with a long-acting agent such as diazepam is recommended before commencing withdrawal. Chlordiazepoxide (Librium), a long-acting benzodiazepine, is gaining attention as an alternative to diazepam in substance abusers dependent on benzodiazepines due to its decreased abuse potential. In individuals dependent on benzodiazepines who have been using benzodiazepines long-term, taper regimens of 6–12 months have been recommended and found to be more successful. More rapid detoxifications e.g. of a month are not recommended as they lead to more severe withdrawal symptoms.

Tolerance leads to a reduction in GABA receptors and function; when benzodiazepines are reduced or stopped this leads to an unmasking of these compensatory changes in the nervous system with the appearance of physical and mental withdrawal effects such as anxiety, insomnia, autonomic hyperactivity and possibly seizures.

Substance dependence also known as drug dependence is an adaptive state that develops from repeated drug administration, and which results in withdrawal upon cessation of drug use. A "drug addiction", a distinct concept from substance dependence, is defined as compulsive, out-of-control drug use, despite negative consequences. An "addictive drug" is a drug which is both rewarding and reinforcing. ΔFosB, a gene transcription factor, is now known to be a critical component and common factor in the development of virtually all forms of behavioral addiction and drug addictions, but not dependence.

Within the framework of the 4th edition of the "Diagnostic and Statistical Manual of Mental Disorders" ("DSM-IV"), substance dependence is redefined as a drug addiction, and can be diagnosed without the occurrence of a withdrawal syndrome. It is now described accordingly: "When an individual persists in use of alcohol or other drugs despite problems related to use of the substance, substance dependence may be diagnosed. Compulsive and repetitive use may result in tolerance to the effect of the drug and withdrawal symptoms when use is reduced or stopped. This, along with Substance Abuse are considered Substance Use Disorders."

The DSM definition of addiction can be boiled down to compulsive use of a substance (or engagement in an activity) despite ongoing negative consequences. The medical community makes a distinction between physical dependence (characterized by symptoms of physical withdrawal symptoms, like tremors and sweating) and psychological dependence (emotional-motivational withdrawal symptoms). Physical dependence is simply needing a substance to function. Humans are all physically dependent upon oxygen, food and water. A drug can cause physical dependence and not psychological dependence (for example, some blood pressure medications, which can produce fatal withdrawal symptoms if not tapered) and some can cause psychological dependence without physical dependence (the withdrawal symptoms associated with cocaine are all psychological, there is no associated vomiting or diarrhea as there is with opiate withdrawal).

There are several different screening tools that have been validated for use with adolescents such as the CRAFFT and adults such as the CAGE.

Withdrawal is the body's reaction to abstaining from a substance upon which a person has developed a dependence syndrome. When dependence has developed, cessation of substance use produces an unpleasant state, which promotes continued drug use through negative reinforcement; i.e., the drug is used to escape or avoid re-entering the associated withdrawal state. The withdrawal state may include physical-somatic symptoms (physical dependence), emotional-motivational symptoms (psychological dependence), or both. Chemical and hormonal imbalances may arise if the substance is not introduced. Psychological stress may also result if the substance is not re-introduced.

Infants also suffer from substance withdrawal, known as Neonnatal Abstinence Syndrome (NAS) which has severe and life-threatening effects on growing fetus. Addiction to drugs and alcohol in expecting mothers does not only cause NAS but also an array of other issues which can continually affect the infant throughout his/her lifetime. The type of drug which was abused during the months of pregnancy has many different effects on the child which can affect the infant in many ways throughout his/her life.

Physical dependence on a substance is defined by the appearance of characteristic physical withdrawal symptoms when the substance is suddenly discontinued. Opiates, benzodiazepines, barbiturates, alcohol and nicotine induce physical dependence. On the other hand, some categories of substances share this property and are still not considered addictive: cortisone, beta blockers and most antidepressants are examples.

Some substances induce physical dependence or physiological tolerance - but not addiction — for example many laxatives, which are not psychoactive; nasal decongestants, which can cause rebound congestion if used for more than a few days in a row; and some antidepressants, most notably venlafaxine, paroxetine and sertraline, as they have quite short half-lives, so stopping them abruptly causes a more rapid change in the neurotransmitter balance in the brain than many other antidepressants. Many non-addictive prescription drugs should not be suddenly stopped, so a doctor should be consulted before abruptly discontinuing them.

The speed with which a given individual becomes addicted to various substances varies with the substance, the frequency of use, the means of ingestion, the intensity of pleasure or euphoria, and the individual's genetic and psychological susceptibility. Some people may exhibit alcoholic tendencies from the moment of first intoxication, while most people can drink socially without ever becoming addicted. Opioid dependent individuals have different responses to even low doses of opioids than the majority of people, although this may be due to a variety of other factors, as opioid use heavily stimulates pleasure-inducing neurotransmitters in the brain. Nonetheless, because of these variations, in addition to the adoption and twin studies that have been well replicated, much of the medical community is satisfied that addiction is in part genetically moderated. That is, one's genetic makeup may regulate how susceptible one is to a substance and how easily one may become attached to a pleasurable routine.

Eating disorders are complicated pathological mental illnesses and thus are not the same as addictions described in this article. Eating disorders, which some argue are not addictions at all, are driven by a multitude of factors, most of which are highly different from the factors behind addictions described in this article. It has been reported, however, that patients with eating disorders can successfully be treated with the same non-pharmacological protocols used in patients with chemical addiction disorders.

Gambling is another potentially addictive behavior with some biological overlap. Conversely gambling urges have emerged with the administration of Mirapex (pramipexole), a dopamine agonist.

The obsolete term physical addiction is deprecated, because of its connotations. In modern pain management with opioids physical dependence is nearly universal. High-quality, long-term studies are needed to better delineate the risks and benefits of chronic opiate use.

Amphetamine dependence refers to a state of psychological dependence on a drug in the amphetamine class. In individuals with substance use disorder (problematic use or abuse with dependence), psychotherapy is currently the best treatment option as no pharmacological treatment has been approved. Tolerance is expected to develop with regular substituted amphetamine use. When substituted amphetamines are abused, drug tolerance develops rapidly.

Severe withdrawal associated with dependence from recreational substituted amphetamine use can be difficult for a user to cope with. Long-term use of certain substituted amphetamines, particularly methamphetamine, can reduce dopamine activity in the brain. Psychostimulants that increase dopamine and mimic the effects of substituted amphetamines, but with lower abuse liability, could theoretically be used as replacement therapy in amphetamine dependence. However, the few studies that used amphetamine, bupropion, methylphenidate and modafinil as a replacement therapy did not result in less methamphetamine use or craving.

In 2013, overdose on amphetamine, methamphetamine, and other compounds implicated in an "amphetamine use disorder" resulted in an estimated 3,788 deaths worldwide (3,425–4,145 deaths, 95% confidence).

Barbiturate dependence develops with regular use of barbiturates. This in turn may lead to a need for increasing doses of the drug to get the original desired pharmacological or therapeutic effect. Barbiturate use can lead to both addiction and physical dependence, and as such they have a high potential for abuse. Management of barbiturate dependence involves considering the affected person's age, comorbidity and the pharmacological pathways of barbiturates. Psychological addiction to barbiturates can develop quickly. The GABA receptor, one of barbiturates' main sites of action, is thought to play a pivotal role in the development of tolerance to and dependence on barbiturates, as well as the euphoric "high" that results from their abuse. The mechanism by which barbiturate tolerance develops is believed to be different from that of ethanol or benzodiazepines, even though these drugs have been shown to exhibit cross-tolerance with each other. The management of a physical dependence on barbiturates is stabilisation on the long-acting barbiturate phenobarbital followed by a gradual titration down of dose. The slowly eliminated phenobarbital lessens the severity of the withdrawal syndrome and reduces the chances of serious barbiturate withdrawal effects such as seizures. Antipsychotics are not recommended for barbiturate withdrawal (or other CNS depressant withdrawal states) especially clozapine, olanzapine or low potency phenothiazines e.g. chlorpromazine as they lower the seizure threshold and can worsen withdrawal effects; if used extreme caution is required.

Nicotine dependence develops over time as a person continues to smoke. The risk for the development of dependence and how long it takes to become dependent differs from person to person; there is not a clear consensus on how long it takes for dependence to develop.

Nicotine dependence results in daily, heavy usage of cigarettes and produces withdrawal symptoms such as urges to smoke, negative moods, and difficulty concentrating, when the person stops smoking. These withdrawal symptoms are so unpleasant that smokers very frequently return to smoking. However, while it is known what nicotine dependence does—permits heavy smoking and causes severe withdrawal symptoms and relapse back to smoking—it is hard to measure nicotine dependence apart from these consequences.

Nicotine dependence has been classified as a chronic, relapsing disease. In other words, it is a long-term disorder that may have periods of relapse and remission that require repeated intervention, similar to other chronic conditions such as diabetes or hypertension. This perspective reinforces the idea that nicotine dependence is not a bad habit but an actual disease that requires ongoing treatment.

From the ICD-9 database:

- A chronic disease in which a person craves drinks that contain alcohol and is unable to control his or her drinking. A person with this disease also needs to drink greater amounts to get the same effect and has withdrawal symptoms after stopping alcohol use. Alcoholism affects physical and mental health, and can cause problems with family, friends, and work.

- A disorder characterized by a pathological pattern of alcohol use that causes a serious impairment in social or occupational functioning.

- A primary, chronic disease with genetic, psychosocial, and environmental factors influencing its development and manifestations. The disease is often progressive and fatal. It is characterized by impaired control over drinking, preoccupation with the drug alcohol, use of alcohol despite adverse consequences, and distortions in thinking, most notably denial. Each of these symptoms may be continuous or periodic. (morse & flavin for the joint commission of the national council on alcoholism and drug dependence and the american society of addiction medicine to study the definition and criteria for the diagnosis of alcoholism: in jama 1992;268:1012-4)

- For most adults, moderate alcohol use is probably not harmful. However, about 18 million adult Americans are alcoholics or have alcohol problems. Alcoholism is a disease with four main features:

- craving - a strong need to drink

- loss of control - not being able to stop drinking once you've started

- physical dependence - withdrawal symptoms, such as nausea, sweating, or shakiness when you don't drink

- tolerance - the need to drink greater amounts of alcohol to feel the same effect

- Temporary mental disturbance marked by muscle incoordination and paresis as the result of excessive alcohol ingestion.

Cocaine is a powerful stimulant known to make users feel energetic, happy, talkative, etc. In time, negative side effects include increased body temperature, irregular or rapid heart rate, high blood pressure, increased risk of heart attacks, strokes and even sudden death from cardiac arrest. Many habitual abusers develop a transient, manic-like condition similar to amphetamine psychosis and schizophrenia, whose symptoms include aggression, severe paranoia, restlessness, confusion and tactile hallucinations; which can include the feeling of insects under the skin (formication), also known as "coke bugs", during binges. Users of cocaine have also reported having thoughts of suicide, unusual weight loss, trouble maintaining relationships, and an unhealthy, pale appearance.

Nicotine dependence, or tobacco use disorder, is a state of dependence upon nicotine. There are different ways of measuring nicotine dependence. Some nicotine dependence assessments focus on key physical dependence outcomes like the development of tolerance which allows people to smoke heavily. Other assessments ask about psychosocial outcomes or underlying mechanisms of dependence. These different assessments either characterize dependence as a continuous construct or use cut-offs to diagnose whether or not a person is dependent.

Nicotine dependence is especially a concern among some populations such as those with co-occurring mental illness. There are evidence-based nicotine dependence treatments that include both medication and psychosocial interventions that can significantly increase a smoker’s chances of quitting successfully.

Withdrawal effects caused by sedative-hypnotics discontinuation, such as benzodiazepines, barbiturates, or alcohol, can cause serious medical complications. They are cited to be more hazardous to withdraw from than opioids. Users typically receive little advice and support for discontinuation. Some withdrawal symptoms are identical to the symptoms for which the medication was originally prescribed, and can be acute or protracted in duration. Onset of symptoms from long half-life benzodiazepines might be delayed for up to three weeks, although withdrawal symptoms from short-acting ones often present early, usually within 24–48 hours. There may be no fundamental differences in symptoms from either high or low dose discontinuation, but symptoms tend to be more severe from higher doses.

Daytime reemergence and rebound withdrawal symptoms, sometimes confused with interdose withdrawal, may occur once dependence has set in. 'Reemergence' is the return of symptoms for which the drug was initially prescribed, in contrast, 'rebound' symptoms are a return of the symptoms for which the benzodiazepine was initially taken, but at a more intense level than before; whereas 'interdose withdrawal' is when a prior dosage of drug wears off and beginnings of an entirely new cycle of withdrawal sets in, the symptoms of which dissipate upon taking the next dosage but afterwhich yet another entirely new cycle of withdrawal begins when that dosage wears off, a new onset of withdrawal between each dosage thus called 'interdose withdrawal' and if not properly treated can recur indefinitely in a vicious circle (for which consider a benzo with a long half life (eg. Valium) so the drug does not wear off between doses). Withdrawal symptoms may appear for the first time during dose reduction, and include insomnia, anxiety, distress, weight loss, dizziness, night sweats, shakes, muscle twitches, aphasia, panic attacks, depression, derealization, paranoia, etc., and are more commonly associated with short-acting benzodiazepines discontinuation, like triazolam. Daytime symptoms can occur after a few days to a few weeks of administration of nightly benzodiazepine use or z-drugs such as zopiclone; withdrawal-related insomnia rebounds worse than baseline even when benzodiazepines are used intermittently.

The following symptoms may emerge during gradual or abrupt dosage reduction:

Rapid discontinuation may result in a more serious syndrome

As withdrawal progresses, patients often find their physical and mental health improves with improved mood and improved cognition.

Treatment for physical dependence depends upon the drug being withdrawn and often includes administration of another drug, especially for substances that can be dangerous when abruptly discontinued or when previous attempts have failed. Physical dependence is usually managed by a slow dose reduction over a period of weeks, months or sometimes longer depending on the drug, dose and the individual. A physical dependence on alcohol is often managed with a cross tolerant drug, such as long acting benzodiazepines to manage the alcohol withdrawal symptoms.

Benzodiazepine withdrawal syndrome—often abbreviated to benzo withdrawal—is the cluster of symptoms that emerge when a person who has taken benzodiazepines, either medically or recreationally, and has developed a physical dependence undergoes dosage reduction or discontinuation. Development of physical dependence and/or addiction and the resulting withdrawal symptoms, some of which may last for years, may result from either drug-seeking behaviors or from taking the medication as prescribed. Benzodiazepine withdrawal is characterized by sleep disturbance, irritability, increased tension and anxiety, panic attacks, hand tremor, sweating, difficulty with concentration, confusion and cognitive difficulty, memory problems, dry retching and nausea, weight loss, palpitations, headache, muscular pain and stiffness, a host of perceptual changes, hallucinations, seizures, psychosis, and suicide (see "Signs and Symptoms" section below for full list). Further, these symptoms are notable for the manner in which they wax and wane and vary in severity from day to day or week by week instead of steadily decreasing in a straightforward monotonic manner.

It is a potentially serious condition, and is complex and often protracted in time course. Long-term use, defined as daily use for at least three months, is not desirable because of the associated increased risk of dependence, dose escalation, loss of efficacy, increased risk of accidents and falls, particularly for the elderly, as well as cognitive, neurological, and intellectual impairments. Use of short-acting hypnotics, while being effective at initiating sleep, worsen the second half of sleep due to withdrawal effects. Nevertheless, long-term users of benzodiazepines should not be forced to withdraw against their will.

Benzodiazepine withdrawal can be severe and can provoke life-threatening withdrawal symptoms, such as seizures, particularly with abrupt or overly rapid dosage reduction from high doses or long time users. A severe withdrawal response can nevertheless occur despite gradual dose reduction, or from relatively low doses in short time users, even after a single large dose in animal models. A minority of individuals will experience a protracted withdrawal syndrome whose symptoms may persist at a sub-acute level for months, or years after cessation of benzodiazepines. The likelihood of developing a protracted withdrawal syndrome can be minimized by a slow, gradual reduction in dosage.

Chronic exposure to benzodiazepines causes neural adaptations that counteract the drug's effects, leading to tolerance and dependence. Despite taking a constant therapeutic dose, long-term use of benzodiazepines may lead to the emergence of withdrawal-like symptoms, particularly between doses. When the drug is discontinued or the dosage reduced, withdrawal symptoms may appear and remain until the body reverses the physiological adaptations. These rebound symptoms may be identical to the symptoms for which the drug was initially taken, or may be part of discontinuation symptoms. In severe cases, the withdrawal reaction may exacerbate or resemble serious psychiatric and medical conditions, such as mania, schizophrenia, and, especially at high doses, seizure disorders. Failure to recognize discontinuation symptoms can lead to false evidence for the need to take benzodiazepines, which in turn leads to withdrawal failure and reinstatement of benzodiazepines, often to higher doses.

Awareness of the withdrawal reactions, individualized taper strategies according to withdrawal severity, the addition of alternative strategies such as reassurance and referral to benzodiazepine withdrawal support groups, all increase the success rate of withdrawal.

Depending on the actual compound, drug abuse including alcohol may lead to health problems, social problems, morbidity, injuries, unprotected sex, violence, deaths, motor vehicle accidents, homicides, suicides, physical dependence or psychological addiction.

There is a high rate of suicide in alcoholics and other drug abusers. The reasons believed to cause the increased risk of suicide include the long-term abuse of alcohol and other drugs causing physiological distortion of brain chemistry as well as the social isolation. Another factor is the acute intoxicating effects of the drugs may make suicide more likely to occur. Suicide is also very common in adolescent alcohol abusers, with 1 in 4 suicides in adolescents being related to alcohol abuse. In the USA approximately 30% of suicides are related to alcohol abuse. Alcohol abuse is also associated with increased risks of committing criminal offences including child abuse, domestic violence, rapes, burglaries and assaults.

Drug abuse, including alcohol and prescription drugs, can induce symptomatology which resembles mental illness. This can occur both in the intoxicated state and also during the withdrawal state. In some cases these substance induced psychiatric disorders can persist long after detoxification, such as prolonged psychosis or depression after amphetamine or cocaine abuse. A protracted withdrawal syndrome can also occur with symptoms persisting for months after cessation of use. Benzodiazepines are the most notable drug for inducing prolonged withdrawal effects with symptoms sometimes persisting for years after cessation of use. Abuse of hallucinogens can trigger delusional and other psychotic phenomena long after cessation of use.

Cannabis may trigger panic attacks during intoxication and with continued use, it may cause a state similar to dysthymia. Researchers have found that daily cannabis use and the use of high-potency cannabis are independently associated with a higher chance of developing schizophrenia and other psychotic disorders.

Severe anxiety and depression are commonly induced by sustained alcohol abuse, which in most cases abates with prolonged abstinence. Even sustained moderate alcohol use may increase anxiety and depression levels in some individuals. In most cases these drug induced psychiatric disorders fade away with prolonged abstinence.

According to the DSM-IV criteria for alcohol dependence, at least three out of seven of the following criteria must be manifest during a 12-month period:

- Tolerance

- Withdrawal symptoms or clinically defined alcohol withdrawal syndrome

- Use in larger amounts or for longer periods than intended

- Persistent desire or unsuccessful efforts to cut down on alcohol use

- Time is spent obtaining alcohol or recovering from effects

- Social, occupational and recreational pursuits are given up or reduced because of alcohol use

- Use is continued despite knowledge of alcohol-related harm (physical or psychological)

Impulsivity is characterized by actions based on sudden desires, whims, or inclinations rather than careful thought. Individuals with substance abuse have higher levels of impulsivity, and individuals who use multiple drugs tend to be more impulsive. A number of studies using the Iowa gambling task as a measure for impulsive behavior found that drug using populations made more risky choices compared to healthy controls. There is a hypothesis that the loss of impulse control may be due to impaired inhibitory control resulting from drug induced changes that take place in the frontal cortex. The neurodevelopmental and hormonal changes that happen during adolescence may modulate impulse control that could possibly lead to the experimentation with drugs and may lead to the road of addiction. Impulsivity is thought to be a facet trait in the neuroticism personality domain (overindulgence/negative urgency) which is prospectively associated with the development of substance abuse.