Medicinal-Induced Behavior Disorders

Key points

Medication-induced behavioral side effects

In daily neurology practice, we see patients who present with behavioral changes that may not be explained by the primary diagnosis. Because some of our patients also have psychiatric diagnoses, the practitioner must have an open mind to find the cause of behavioral changes. When the secondary causes are being worked up, a complete list of the medications of each patient should be looked at closely, because medication side effects include behavioral changes. Some medications act as neurotoxins

Central nervous system toxicity

“That guy has delta MS.” The meaning of this phrase is easily understood by medical personnel from the lowest levels of training to the most senior clinicians. Unfortunately, however, as a diagnosis it is about as helpful as saying that a patient is sick. Recognition of the syndrome of CNS toxicity is relatively simple; determining the cause and therefore the appropriate management can be a challenge.

A change in mental status can be thought of as too excited (agitation, mania, hallucinosis,

Antihypertensive agent–induced behavioral side effects

Antihypertensive agents are among the most commonly prescribed medications to the general population. Among them, the commonly used β-adrenoreceptor antagonists (ß-blockers) have been reported to cause behavioral side effects such as drowsiness, fatigue, lethargy, sleep disorders, nightmares, depressive moods, and hallucinations. These undesirable actions indicate that ß-blockers affect not only peripheral autonomic activity, but also some CNS function. The various hypothesized centrally

Opioid-induced behavioral side effects

Chronic painful conditions are being increasingly treated with opioid medications in addition to their traditional role in the management of acute pain and cancer-related terminal pain. Psychological addiction, abuse, and diversion of these medications is a growing threat, because these agents are increasingly available to the general public. The commonly reported side effects of opioids include nausea, vomiting, constipation, dizziness, sedation, respiratory depression, tolerance, and physical

Antibiotic-induced behavioral side effects

Antibiotics are among the most commonly used medications in inpatient and outpatient settings. Various neuropsychiatric side effects are reported that may be dose dependent or idiosyncratic in nature.

Antiepileptic medication–induced behavioral side effects

The major categories of behavioral changes caused by antiepileptic drugs (AEDs) include mood alterations, withdrawal syndromes, intoxication and forced normalization (FN).⁵⁶ Psychotropic effects can be either positive or negative depending on the drug used, the dosage, duration, efficacy, and the patient’s psychological predisposition. Owing to the variability of associated circumstances, the exact frequency of side effects is difficult to estimate. A case series of patients on AEDs who

Classic antiepileptic drugs

It is not unusual for epileptic patients (both children and adults) to develop depression after starting AED treatment.62, 63, 64 Children commonly develop a conduct disorder with features similar to attention deficit hyperactivity disorder. Hyperactivity is seen most commonly with phenobarbital. Developmentally delayed patients seem to be particularly susceptible to aggressive behavior and irritability when treated with barbiturates.

Steroid-induced behavioral side effects

Corticosteroid (CS) treatment is important in both acute (eg, asthma exacerbation) and chronic medical conditions (eg, systemic lupus erythematosus). Somatic side effects have been researched extensively and described widely, but less attention has been paid to neuropsychiatric adverse effects.

Adverse psychological side effects (APSE) from CS range from mild mood or cognitive deficits and emotional lability to severe psychotic symptoms, such as persecutory delusions or auditory hallucinations.⁹⁷

Behavioral side effects of medications to treat Parkinson’s disease

The main classes of drugs used to treat Parkinson’s disease (PD) are levodopa, including carbidopa/levodopa combination pills, dopamine agonists (DAs), catechol-O-methyltransferase enzyme inhibitors, monoamine oxidase inhibitors, amantadine, and anticholinergics. The primary cause of behavioral disturbances in PD is dopamine replacement treatment with excessive or aberrant dopamine receptor stimulation. Dopamine has many important functions, including motor function, a role in the brain’s

Behavioral side effects of psychiatric medications

Individuals vary in their response to psychotropic and antidepressant medications, a critical problem when trying to manage psychotic disorders. This variability is multifactorial and may be owing to age, gender, comorbid medical conditions, other concurrent medications, and environmental factors. Genetic polymorphism, variations in pharmacokinetics, and pharmacodynamics also influence the treatment response. Cytochrome (CYP) enzymes, serotonin, and dopamine gene variants are known to

Behavioral side effects of human immunodeficiency virus and highly active antiretroviral therapy

Patients with human immunodeficiency virus (HIV) infection can suffer from various neuropsychiatric symptoms. They may be caused by the direct toxic effects of the virus on the CNS, comorbid psychiatric conditions, substance abuse, immunodeficiency leading to CNS opportunistic infections, activity of immune mediators, metabolic decompensation, and/or the side effects of the antiretroviral therapy. The discovery of antiretroviral drugs has changed the outlook of HIV in developed countries. It is

Chemotherapy-induced behavioral side effects

Although chemotherapeutic agents can achieve great success in the treatment of various cancers, some of these agents cause severe debilitating side effects that may warrant dose reduction or cessation of therapy. The commonly reported neuropsychiatric side effects of chemotherapy include fatigue, cognitive deficits, memory impairment, decreased attention span, deficiencies in executive functioning, and motivational deficits; they also cause neuropathy. These symptoms, which develop during

Immunotherapy-induced behavioral side effects

Commonly used immunotherapy medications like mycophenolate, interferon (INF)-α, INF-β, and interleukin (IL)-2 have all been shown to have neuropsychiatric side effects, especially depression.²²⁰

Conclusion

The neurobehavioral effects of medications are relatively common and potentially life threatening. The nervous system can be affected whether the drug is targeted to treat a brain disorder or not. Sometimes the presentation follows a well-known pattern and the toxicity is relatively easy to diagnose. Other signs and symptoms may be subtle, not recognized by patients or caregivers, or ignored leading to prolonged problems and risk of more serious complications.

The world’s population is aging,