High rates of suicide also occur in those who have alcohol-related problems. It is usually possible to differentiate between alcohol-related depression and depression that is not related to alcohol intake by taking a careful history of the patient. Depression and other mental health problems associated with alcohol misuse may be due to distortion of brain chemistry, as they tend to improve on their own after a period of abstinence. Benzodiazepine-induced
Benzodiazepines, such as alprazolam, clonazepam, lorazepam and diazepam, can cause both depression and mania.Benzodiazepines are a class of medication commonly used to treat anxiety, panic attacks and insomnia, and are also commonly misused and abused. Those with anxiety, panic and sleep problems commonly have negative emotions and thoughts, depression, suicidal ideations, and often have comorbid depressive disorders. While the anxiolytic and hypnotic effects of benzodiazepines disappear as tolerance develops, depression and impulsivity with high suicidal risk commonly persist. These symptoms are "often interpreted as an exacerbation or as a natural evolution of previous disorders and the chronic use of sedatives is overlooked". Benzodiazepines do not prevent the development of depression, can exacerbate preexisting depression, can cause depression in those with no history of it, and can lead to suicide attempts. Risk factors for suicide and suicide attempts while using benzodiazepines include high dose prescriptions (even in those not misusing the medications), benzodiazepine intoxication, and underlying depression.The long-term use of benzodiazepines may have a similar effect on the brain as alcohol, and are also implicated in depression.
Examples include:

Prilocaine hydrochloride and epinephrine (trade name Citanest Forte)
Lidocaine, bupivacaine, and epinephrine (recommended final concentrations of 0.5, 0.25, and 0.5%, respectively)
Iontocaine, consisting of lidocaine and epinephrine
Septocaine (trade name Septodont), a combination of articaine and epinephrineOne combination product of this type is used topically for surface anaesthesia, TAC (5-12% tetracaine,1/2000 (0.05%, 500 ppm, 1⁄2 per mille) adrenaline, 4 or 10% cocaine). Using LA with vasoconstrictor is safe in regions supplied by end arteries. The commonly held belief that LA with vasoconstrictor can cause necrosis in extremities such as the nose, ears, fingers, and toes (due to constriction of end arteries), is invalidated, since no case of necrosis has been reported since the introduction of commercial lidocaine with epinephrine in 1948. Ester group
Benzocaine
Chloroprocaine
Cocaine
Cyclomethycaine
Dimethocaine (Larocaine)
Piperocaine
Propoxycaine
Procaine (Novocaine)
Proparacaine
Tetracaine (Amethocaine)

Amide group
Articaine
Bupivacaine
Cinchocaine (Dibucaine)
Etidocaine
Levobupivacaine
Lidocaine (Lignocaine)
Mepivacaine
Prilocaine
Ropivacaine
Trimecaine

Naturally derived
Saxitoxin
Neosaxitoxin
Tetrodotoxin
Menthol
Eugenol
Cocaine
SpilantholMost naturally occurring local anesthetics with the exceptions of menthol, eugenol and cocaine are neurotoxins, and have the suffix -toxin in their names. Cocaine binds the intracellular side of the channels while saxitoxin, neosaxitoxin and tetrodotoxin bind to the extracellular side of sodium channels. History
In Peru, the ancient Incas are believed to have used the leaves of the coca plant as a local anaesthetic in addition to its stimulant properties. It was also used for slave payment and is thought to play a role in the subsequent destruction of Incas culture when Spaniards realized the effects of chewing the coca leaves and took advantage of it. Cocaine was first used as a local anesthetic in 1884.