Does the patient have signs of depression, anxiety, or mania? Signs of major depression include depressed mood, changes in eating and sleeping patterns, loss of energy and initiative, low self-esteem, poor concentration, lack of enjoyment of previously pleasurable activities, and self-destructive or suicidal thoughts and behavior. Anxiety disorders are characterized by preoccupation with worrisome thoughts. Mania causes patients to be abnormally active and cognitively disorganized.
These disorders are often considered psychiatric in origin and may be due to imbalances in neurotransmitter systems in several different areas of the brain. However, features of these disorders are also seen in focal brain lesions and in toxic or metabolic abnormalities such as thyroid dysfunction.
Some of the most difficult and interesting diagnostic dilemmas arise because of overlap and confusion between psychiatric and neurologic disorders. Thus, depressed patients with somatization or conversion disorders (which will be discussed later in the chapter) often have complaints such as pain, numbness, weakness, or even seizurelike activity and are therefore referred to neurologists for evaluation. Likewise, neurologic disorders such as brain tumors, strokes, metabolic derangements, and so on can produce confusional states or bizarre behavior that may be misinterpreted as psychiatric in origin.