To help illuminate the causes and natural history of substance abuse disorders, and given increasing interest in drug therapy for the treatment of addiction, this reference volume provides a comprehensive technical review of the pharmacology of each type of drug known to induce abuse or dependence.

Sections correspond to drug classes listed in the American Psychiatric Association’s 1994 Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV): alcohol; caffeine; cannabis; cocaine; hallucinogens; inhalants; nicotine; opiates; sedatives, hypnotics, and anxiolytics; and amphetamines. A final section addresses other substances of abuse, including anabolic steroids, ecstasy, and phencyclidine.

In an attempt to integrate neurological, behavioral, and clinical material, each section provides separate chapters on pharmacology, behavioral pharmacology, and psychological and psychiatric consequences. Presentations review human and animal studies (including conflicting or indeterminate data), mechanisms of action, variables related to dose and drug interactions, different effects of closely related specific drugs, and voluminous additional information to provide a panoramic neurobehavioral view. The book has many contributors, numerous tables, extensive references, and a detailed index.

An introduction notes that no common feature has been found for all drugs that lead to abuse or dependence. Drugs’ capacity to produce intoxication, tolerance, and physical dependence and the severity of withdrawal symptoms vary widely. Abusable drugs may provide positive reinforcement, such as enhancing energy, arousal, or euphoria; or negative reinforcement, relieving fatigue, stress, or depression. This ability to alter emotions, cognition, or behavior is not unique to abusable drugs.

Although definitions vary, like DSM-IV this book distinguishes drug abuse from dependence. Abuse criteria include consumption in difficult or dangerous circumstances and interference with normal activities. Dependence may involve tolerance, withdrawal symptoms, loss of control, relinquishing of personal and social roles, and extensive efforts to maintain use.

The editors acknowledge that understanding substance abuse disorders requires examining the contributions of genetic, developmental, neurobiological, behavioral, and social policy factors, as well as the pharmacological properties of drugs. There has been little research on individual and gender differences in drug response and vulnerability to abuse disorders and dependence.

Many patients with schizophrenia do not take their medication as prescribed. Researchers have been studying ways to improve compliance by providing long-acting relief. Data suggest that a long-acting, injectable formulation of risperidone (Risperdal/Janssen) provides consistently reliable symptom relief when administered as an intramuscular injection given every two weeks. The medication is gradually released to provide consistent blood levels from tiny microspheres made of a biodegradable polymer.

Data collected by researchers from the National Institute of Mental Health’s Epidemiologic Catchment Area Program suggest that the risk of psychiatric illness may be greater in patients who have multiple, chronic, nonpsychiatric medical conditions than in those individuals who do not have concurrent illnesses. The rate of depression coexisting with medical illnesses has been known to vary with the illness; however, this rate usually does exceed that reported for the general population.

As would be expected, patients suffering from cancer, cardiovascular disease, dementia, diabetes, Parkinson’s disease and stroke are likely candidates to exhibit depressive symptoms associated with their illness. These patients may develop somatic complaints that are typically associated with depression, such as pain, low energy and sexual dysfunctioning.

Recognizing Depression

The signs and symptoms associated with the clinical presentation of a major depressive episode are categorized by health-care pro-viders into psychological and somatic symptoms and vegetative signs. Psychological and somatic symptoms associated with depression include sadness and a sad expression, a markedly diminished interest in all aspects of life, hopelessness, low self-esteem or feelings of worthlessness, inappropriate guilt, recurrent thoughts of death (possibly including suicide with or without a specific attempt) and complaints of vague aches and pains.

Vegetative signs include changes in appetite or weight (usually loss of weight), sleep disturbances (usually early morning wakening), decreased energy and unexplained fatigue, psychomotor retardation (diminished ability to concentrate or remember, etc.) decreased sex drive, irregular menses, gastrointestinal upset (constipation, diarrhea, etc.) and biochemical abnormalities.

Particularly common symptoms of depression include a depressed mood, decreased interest or pleasure in activities, changes in appetite, weight or sleep, psychomotor agitation or retardation, loss of energy, inability to concentrate, indecisiveness and thoughts of death, dying or suicide. It is especially alarming to note that when they are left untreated, 25%–30% of adult patients with depression will commit suicide. Specific diagnostic criteria for a major depressive episode have been established and are published in the Diagnostic and Statistical Manual of Mental Disorders.

Other important depressive illnesses that should be considered include dysthymia, atypical depression and delusional depression. Individuals with dysthymia experience depressed moods most of the time for at least two years, are never without a depressed mood more than two months and have at least two vegetative symptoms. Patients with atypical depression are found to have a persistent feeling of anxiety along with symptoms of depression. These individuals often have a reversal of vegetative signs (overeating instead of losing weight, hypersomnia instead of insomnia) and also maintain some degree of enjoyment in activities. The patient with delusional depression has significant psychotic symptoms often resulting in a need for antipsychotic medication in combination with antidepressant drugs. Electroconvulsive therapy (ECT) is also an important means of treating patients with delusional depression.

Drug-Induced Depression

Pharmacists must consider the possibility of drug-induced depression in their home health care patients, most of whom are maintained on prescription or OTCmedication. Many drugs have been implicated, including anti-inflammatory agents (indomethacin, etc.), analgesics (pentazocine, etc.), antimicrobial agents (sulfonamides, ethambutol, cycloserine, etc.), cardiovascular/antihypertensive drugs (digitalis, clonidine, guanethidine, methyldopa, reserpine, hydralazine, propranolol, prazocin, etc.), medications that affect the central nervous system (amantadine, levodopa, barbiturates, chloral hydrate, carbamazepine, benzodiazepines, alcohol, etc.), hormonal agents (corticosteroids, estrogen, progesterone, etc.) and other miscellaneous drugs (disulfiram, physostigmine, antineoplastic drugs, exposure to organic pesticides, etc.).

Whenever there is suspicion that the patient’s medication regimen is responsible for causing the depression, the clinician should not only consider the drugs that the patient is taking, but also consider the temporal relationship between starting a particular drug and the occurrence of the depressive symptoms, the medical necessity for the drugs or drugs that are being used, the potential for a drug interaction to be responsible and the possibility that the patient is misusing drugs of abuse or alcohol.

Other Factors to Consider

Clinicians are often challenged when they must differentiate between depression and dementia. This problem results from the high rate of comorbidity and symptom overlap associated with these two disorders. There are some factors that can help with determining which disorder is present. Depression has a relatively rapid onset which differs from the insidious and indeterminate onset of dementia. Both types of patients have a depressed mood; however, the orientation of the depression patient is intact, while that of the dementia patient is impaired.

Another notable difference between these patients is that the patient suffering from depression has a depressed/anxious affect, unlike that of the dementia patient, which is labile and variable. The depressed patient’s ability to concentrate is inconsistent, yet patients with dementia usually have consistent recent memory potential. The disabling nature of depression is often highlighted by patients, which is quite different from dementia patients, who try to conceal their ailment. As would be expected, there is no neurologic deficit that is classically associated with depression; however, this may be present in dementia.

Patient Monitoring

The treatment options for depression include various psychotherapies, ECT, light therapy, monoamine oxidase inhibitors (MAOIs), tricyclic antidepressant drugs (TCAs) and the newer nontricyclic antidepressant agents, such as SSRIs. The potency and complex mechanisms of action of current pharmaceutical therapies require the pharmacist to carefully monitor patients treated with such agents. Pharmacists should check for drug interactions and possible adverse drug reactions by carefully reviewing the patient’s most recent medication profile.

Counseling these patients may become particularly challenging due to the nature of their illness; therefore, it may be advisable or at times even necessary to obtain the assistance of the patient’s caregiver. Although it is beyond the scope of this article to discuss the pharmacologic management of depression in detail, the interested reader is referred to the excellent recent review articles written by Hartman and Watanabe and Jesson for additional information.