Differential Diagnosis

• Single most likely diagnosis
  • Schizoaffective disorder: This diagnosis is the most likely because the patient has a history of episodes with both depressive symptoms (suicidal ideation) and psychotic symptoms (delusions of being bugged by the government, thoughts being reported live on the radio) that have occurred for a significant portion of the total duration of the active and residual portions of the illness. The presence of both mood and psychotic symptoms, with the psychotic symptoms occurring in the absence of a major mood episode (as indicated by the patient's statement of not being depressed at all during some of these episodes), supports this diagnosis.
• Other Likely diagnoses
  • Schizophrenia: This could be considered if the psychotic symptoms were predominant and the depressive symptoms were not as significant or were only present for a short period. However, the history provided suggests a significant overlap of depressive and psychotic symptoms, making schizoaffective disorder more likely.
  • Schizophreniform disorder: This diagnosis is considered for patients with psychotic symptoms that last for less than 6 months. Given the patient's 2-year history of similar episodes, this diagnosis seems less likely.
  • Major depressive disorder with psychotic features: This could be a consideration if the psychotic symptoms only occurred during episodes of depression. However, the patient's history of experiencing delusions outside of what he describes as depressive episodes makes this less likely.
• Do Not Miss diagnoses
  • Substance-induced psychotic disorder: Although the patient denies substance use and the urine drug screen is negative, it's crucial to consider substance-induced psychosis due to its potential for severe consequences if missed. Some substances can cause prolonged psychotic episodes even after the substance is no longer detectable in the urine.
  • Medical conditions presenting with psychiatric symptoms: Various medical conditions (e.g., neurosyphilis, autoimmune disorders, temporal lobe epilepsy) can present with psychotic symptoms. Missing these diagnoses could lead to untreated medical conditions with potentially severe outcomes.
• Rare diagnoses
  • Brief psychotic disorder: Characterized by a sudden onset of psychotic symptoms that last for at least a day but less than a month, followed by a full return to premorbid functioning. This seems unlikely given the patient's 2-year history of episodes.
  • Delusional disorder: This diagnosis involves the presence of one or more non-bizarre delusions for at least a month. If the patient's symptoms were solely delusional without the significant depressive symptoms or other psychotic symptoms (like hallucinations), this could be considered. However, the presence of a broad range of symptoms (depressive episodes, various delusions) makes this less likely.