This case is a 48-year-old male who is referred for an evaluation of behavioral and mood changes. Over the past year, his wife has noticed that he has become increasingly withdrawn and isolated. He no longer enjoys any type of social interaction and prefers to spend his time alone playing card games on his computer. He is college educated with no previous significant medical, neurological, or psychiatric history. He works as an engineer and has been at the same company successfully for the past 20 years. In the past year, his supervisors have noticed that his work quality has declined, and he seems less motivated and "excited" about his job. Tasks he had always completed early are now being done late or not at all, and he appears unconcerned that his job is now in jeopardy.

• Identify the patient's symptoms and the available demographic and historical data.
• Discuss your differential diagnosis and provide a thorough basis for any diagnoses you have included.
• Explain which elements of the nervous system may be involved.
• Determine what (if any) additional testing you would order and how this would be helpful in clarifying the diagnosis.
• Explain recommendations for the patient/family for ongoing functioning (social, occupational, and academic, if applicable).

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