Chapter 49: Common Psychiatric Conditions

ABSTRACT

Psychiatric disorders are common in neurologic disorders, and often occur as a consequence of neurologic disorders. Prompt diagnosis and treatment can improve outcomes, so neurologists should be familiar with typical manifestations and treatments. Depression, apathy, anxiety disorders, PTSD, psychosis, and conversion disorder are common psychiatric conditions encountered by neurologists. All patients should be screened for psychiatric disorders. Neurologists should always evaluate for suicidality and risk of violence to others in patients with psychiatric symptoms. A multimodal biopsychosocial treatment approach—involving medications, psychotherapy, and psychoeducation—is often the most helpful strategy.

GENERAL CONSIDERATIONS

Why should neurologists familiarize themselves with the diagnosis and management of psychiatric illnesses?

• Psychiatric symptoms can occur idiopathically, or as a consequence of a neurologic disorder.¹ At times, psychiatric symptoms may represent the initial presentation of an underlying neurologic illness.

• Psychiatric disorders are common but underdiagnosed, in both the general population and in patients with neurologic diseases.

• Psychiatric symptoms cause immense personal suffering and worsen neurologic outcomes.

• Most psychiatric illnesses respond to treatment, which improves both psychiatric and neurologic outcomes.

• Neurologists need to distinguish between idiopathic psychiatric disorders and psychiatric symptoms due to neurologic disorders or general medical conditions—if they do not, the underlying condition may remain undiagnosed and untreated, and the patient may worsen, when management focuses only on the psychiatric symptoms.

• When psychiatric disorders occur due to a neurologic disorder, they do not necessarily exactly resemble the idiopathic forms described in Diagnostic and Statistical Manual, Fifth Edition (DSM 5), the standard reference criteria used by psychiatrists.

Which neurologic disorders are most likely to be accompanied by psychiatric symptoms?

Neurologic disorders with prominent psychiatric manifestations include:¹

• Stroke

  • Poststroke depression, apathy, post-traumatic stress disorder (PTSD), and anxiety disorders each occur in about one fourth to one third of stroke survivors (some patients have more than one of these conditions)^2,3

• Epilepsy

• Dementia

• Movement disorders (especially Parkinson disease and Huntington disease)

• Limbic encephalitis

• Multiple sclerosis

Can general medical conditions produce both neurologic and psychiatric symptoms?

Yes. Examples include:^4–6

• Endocrinopathies, such as thyroid disorders (even “subclinical” thyroid disorders)

• Vitamin deficiencies, such as B12, folate, and vitamin D deficiency

• Toxic exposures, such as heavy metal poisoning

• Autoimmune disorders, such as systemic lupus erythematosus

• Paraneoplastic syndromes

• Infections, such as HIV and syphilis

• Medication/drug use or withdrawal

Laboratory tests to routinely check on patients with psychiatric symptoms include TSH, FT4, CBC, B12, folate, Vitamin D, HIV, syphilis serology, and urine drug screen.⁷

Can the medications used to treat neurologic disorders cause, worsen, or improve psychiatric symptoms?

Yes. Many commonly used neurologic medications have potential psychiatric effects—both helpful and harmful (Table 49-1).