These adverse reactions are more likely to occur in children, the elderly, and individuals with a history of a substance use disorder, such as an alcohol use disorder, or a history of aggressive behavior. In some people, diazepam may increase the propensity toward self-harming behaviours and, in extreme cases, may provoke suicidal tendencies or acts. Very rarely dystonia can occur.Diazepam may impair the ability to drive vehicles or operate machinery. The impairment is worsened by consumption of alcohol, because both act as central nervous system depressants.During the course of therapy, tolerance to the sedative effects usually develops, but not to the anxiolytic and myorelaxant effects.Patients with severe attacks of apnea during sleep may experience respiratory depression (hypoventilation), leading to respiratory arrest and death.Diazepam in doses of 5 mg or more causes significant deterioration in alertness performance combined with increased feelings of sleepiness. Tolerance and withdrawal
Diazepam, as with other benzodiazepine drugs, can cause tolerance, physical dependence, substance use disorder, and benzodiazepine withdrawal syndrome. Withdrawal from diazepam or other benzodiazepines often leads to withdrawal symptoms similar to those seen during barbiturate or alcohol withdrawal. The higher the dose and the longer the drug is taken, the greater the risk of experiencing unpleasant withdrawal symptoms.Withdrawal symptoms can occur from standard dosages and also after short-term use, and can range from insomnia and anxiety to more serious symptoms, including seizures and psychosis. Withdrawal symptoms can sometimes resemble pre-existing conditions and be misdiagnosed.
In humans, tolerance to the anticonvulsant effects of diazepam occurs frequently. Dependence
Improper or excessive use of diazepam can lead to dependence. At a particularly high risk for diazepam misuse, substance use disorder or dependence are:

People with a history of a substance use disorder or substance dependence Diazepam increases craving for alcohol in problem alcohol consumers. Diazepam also increases the volume of alcohol consumed by problem drinkers. People with severe personality disorders, such as borderline personality disorderPatients from the aforementioned groups should be monitored very closely during therapy for signs of abuse and development of dependence. Therapy should be discontinued if any of these signs are noted, although if dependence has developed, therapy must still be discontinued gradually to avoid severe withdrawal symptoms. Long-term therapy in such instances is not recommended.People suspected of being dependent on benzodiazepine drugs should be very gradually tapered off the drug. Withdrawals can be life-threatening, particularly when excessive doses have been taken for extended periods of time. Equal prudence should be used whether dependence has occurred in therapeutic or recreational contexts.Diazepam is a good choice for tapering for those using high doses of other benzodiazepines since it has a long half-life thus withdrawal symptoms are tolerable. The process is very slow (usually from 14 to 28 weeks) but is considered safe when done appropriately.