Mood Disorders in Neurologic Illness

Substance Use Disorders and Neurologic Illness

Because of the high rates of substance use disorders among the general and clinical populations, and the abuse potential of many medications commonly used in the treatment of neurologic illnesses, the treating neurologist must deal with drug misuse and abuse in practice. The most important tool neurologists must have in their arsenal is the ability to assess for and recognize substance use disorders in their patients. Any treatment plan developed for such patients must include ongoing management of substance abuse issues. After a substance use disorder is diagnosed, the neurologist must make proper referrals to adjunctive support interventions (Alcoholics Anonymous or Narcotics Anonymous) and chemical dependency specialists, and work closely and in collaboration with these components of the patient's overall treatment. The treating neurologist should be aware of the myriad neurologic sequelae of drug use, because most drugs of abuse, including alcohol, can have neurologic manifestations resulting from acute intoxication, acute withdrawal, or chronic use. Drug use (past and present) should be included in the differential diagnosis for any patient with an atypical constellation of symptoms or with isolated neurologic deficits. If the treatment of a neurologic condition requires the use of a potentially addictive substance, particularly when the patient has a history of substance use disorders, then the clinician must minimize the risk of addiction by giving the least addictive substances and developing a plan to manage the use of the drug throughout the treatment period.

Bipolar Disorder in Neurologic Illness

Patients with neurologic illness frequently develop secondary mood disorders that are broadly categorized as unipolar or bipolar illnesses. Although depressive disorders are more commonly seen in neurologic patients, bipolar illnesses can be as debilitating and more difficult to treat. Distinguishing between primary manias (ie, no known brain injury) and secondary manias (ie, etiologically linked to a disease) is important, because secondary manias may present with different symptoms and require different treatments from primary manias. Aggressive treatment of mania improves quality of life, reduces morbidity and mortality, and may prevent worsening of both psychiatric and neurologic disease. Bipolar disorder associated with neurologic illness typically requires treatment with mood stabilizers such as lithium, divalproex sodium, or carbamazepine. A number of other pharmacologic treatments are emerging, many of them using antiepileptic drugs that may have dual use in neurologic patients. Although psychotherapy in combination with medication improves outcome in bipolar illness, psychotherapy alone is not effective for this condition. Treatment of bipolar disorder, especially in the depressed phase, is complicated, and should be referred to a psychiatrist.