Psychoactive Drugs

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Medications that affect people psychologically are called psychoactive drugs. They are often helpful in treating depression, anxiety, insomnia, and other psychological complications that may accompany HIV infection. Psychoactive drugs don't affect the underlying causes of these disorders, but they can provide symptomatic relief to allow people to live more normal lives.

Most of the drugs covered in this section have numerous effects on the nervous system, but each is usually reserved to treat one of the following conditions: anxiety, depression, insomnia, psychosis, or mania.


Anxiety can be defined as persistent nervousness, tension, or panic caused by stress or other psychological causes. Antianxiety drugs (also known as minor tranquilizers) are used to promote relaxation or reduce the physical symptoms of anxiety. Benzodiazepines are a class of psychoactive drugs used to treat anxiety and insomnia. They depress the central nervous system, causing relaxation and sedation. A class of drugs called beta-blockers reduce the shaking or palpitations that may occur when people panic in highly stressful situations, such as job interviews or speaking in public. Other drugs used to treat anxiety include buspirone, some antidepressants, and in special cases, barbiturates.


Everyone feels depressed at times, but when it is prolonged and starts interfering with daily life, support, professional help, and/or psychoactive medications may be appropriate.

Depression is thought to be caused by a reduction in the level of certain chemicals, called neurotransmitters, in the brain. Antidepressants increase the levels of these chemicals in the spaces (called synapses) between nerve cells in the brain. Tricyclic antidepressants (e.g., amoxapine) and serotonin reuptake inhibitors (e.g., fluoxetine or sertraline) prevent cells from absorbing certain neurotransmitters, which increases their levels in the synapses. Monoamine oxidase (MAO) inhibitors increase neurotransmitter levels by interfering with the enzymes that break them down. It takes some time before antidepressants are effective. Ten to fourteen days may elapse after the initial dose before an effect is observable, and it may be six to eight weeks before they are fully effective.

Antidepressants often have severe side effects. MAO inhibitors in particular must be used with caution because they deactivate enzymes in the body that break down chemicals found in many foods, such as meat, cheese, yeast extracts, and red wine. Eating these foods while taking an MAO inhibitor can cause a dramatic rise in blood pressure.


Insomnia has many causes, including anxiety and depression. When the cause is known and can be treated, sleep patterns generally return to normal. When the insomnia is persistent, sleeping drugs may be appropriate.

Most sleeping pills cause sedation by depressing the central nervous system. The most commonly used sleeping medications are the benzodiazepines, but barbiturates and some sedating antihistamines or antidepressant drugs are used as well.

The sleep induced by drugs is not the same as natural sleep. The drugs suppress brain activity and dreaming, and many have a "hangover" effect the next day. Because the drugs are often habit-forming and can cause withdrawal symptoms, they are usually recommended for short-term use only.


Psychosis is a condition in which a person may not be able to think clearly, recognize reality, or act rationally. The precise cause is often unknown, but stress, drug use, heredity, brain injury, or neurological disease may be involved. Drug treatment is usually reserved for when the psychosis is prolonged and interferes with normal life.

Most antipsychosis drugs, including a commonly used class called phenothiazines, work by inhibiting the activity of a neurotransmitter called dopamine. Dopamine is released in excess concentrations in psychosis. Antipsychotics reduce the effect of dopamine by blocking the nerve cell receptors that respond to the chemical.

Antipsychotics also interfere with the activity of another neurotransmitter, called acetylcholine, and after long-term use can cause involuntary muscle movements of the face and hands and other symptoms that resemble Parkinson's disease. These side effects may not be reversible when the drug is stopped.


Mania (exaggerated euphoria or elation) is a type of psychosis that can be caused by a number of medical problems or as a side effects of certain drugs, such as the amphetamines, cocaine, and steroids. The most effective treatment is to remove the cause, if possible. Where the cause is unknown, drug treatment may be appropriate. Rapid or wild mood swings, with peaks of mania and troughs of depression, are usually treated with lithium, a drug that reduces the intensity of the mania and reduces the frequency of mood swings. Acute mania may be treated with haloperidol or phenothiazine drugs including thioridazine, fluphenazine, perphenazine, and trifluoperazine.

The following drugs, listed by class, are profiled in this section:



* fluphenazine * perphenazine * thioridazine * trifluoperazine

Tricyclic Antidepressant

Serotonin Reuptake Inhibitors

* fluoxetine