What is the correct diagnosis and treatment approach for a patient with Bipolar II Disorder, a history of Substance-Induced Manic Psychosis (antidepressant-induced), and multiple depressive episodes, two of which included psychotic features?

Diagnostic Clarification for Antidepressant-Induced Manic Psychosis in Bipolar II Disorder

The correct diagnosis is Bipolar II Disorder with psychotic features during depressive episodes, not Bipolar I Disorder, because the antidepressant-induced manic episode is classified as substance-induced mania per DSM-IV-TR and does not count toward a diagnosis of Bipolar I. 1

Core Diagnostic Principle

• A manic episode precipitated by an antidepressant is characterized as substance-induced per DSM-IV-TR, even when it represents unmasking of the underlying disorder or disinhibition secondary to the agent. 1
• The American Academy of Child and Adolescent Psychiatry explicitly states that antidepressants may destabilize mood or incite a manic episode, but this does not change the diagnosis from Bipolar II to Bipolar I. 1

Distinguishing Bipolar II with Psychotic Depression from Bipolar I

• Bipolar II with psychotic depression is characterized by psychotic symptoms occurring exclusively during major depressive episodes, whereas Bipolar I disorder may have psychotic symptoms during manic, mixed, or depressive episodes. 2
• The critical differentiating feature is that Bipolar II hypomanic episodes last ≥4 days, increase functioning, and never include psychotic features, whereas Bipolar I manic episodes last ≥7 days, cause marked impairment, and may include grandiose, religious, or paranoid delusions during mania. 2
• Since this patient's psychotic features occurred during two depressive episodes (not during hypomania or substance-induced mania), the diagnosis remains Bipolar II Disorder with psychotic features during depression. 2

Clinical Characteristics of Psychotic Bipolar II

• Psychotic symptoms in Bipolar II disorder occur in 3-45% of patients and are allowed by definition only during depressive episodes. 3
• Psychotic Bipolar II patients show higher hospitalization rates, are older at presentation, and demonstrate more melancholic and catatonic features compared to non-psychotic Bipolar II patients. 3
• These patients are less likely to have a family history of bipolar illness than non-psychotic Bipolar II patients. 3

Treatment Approach

Acute Management of Psychotic Depression

• Antipsychotics are first-line treatment during depressive episodes with psychotic features in Bipolar II, with atypical agents preferred. 2
• Mood stabilizers such as lithium or valproate should be initiated concurrently. 2
• Risperidone in combination with either lithium or valproate has demonstrated effectiveness in controlled trials for bipolar disorder with psychotic features. 1, 4

Antidepressant Considerations

• Antidepressants should be avoided or used with extreme caution in this patient, given the history of antidepressant-induced mania. 1
• If antidepressants are deemed necessary for severe depression, they must only be used with at least one mood stabilizer, and SSRIs or bupropion are preferred over tricyclics due to lower switch rates. 1, 5
• Patients with comorbid substance abuse (if applicable) show antidepressant-induced switch rates of 56% even with concomitant mood stabilizers, highlighting the substantial risk. 6
• Specific subtypes including mixed episodes and rapid cycling are extensively associated with antidepressant-induced switch phenomena and antidepressants should be avoided in these presentations. 5

Maintenance Treatment Strategy

• Antipsychotics should be discontinued once the psychotic depressive episode resolves in Bipolar II, unlike in Bipolar I where continuation for at least 12 months is recommended. 2
• Lithium is the only preventive treatment for both depression and hypomania supported by multiple controlled studies and should be considered for long-term maintenance. 7
• Target lithium levels of 0.8-1.2 mEq/L for acute treatment, with baseline labs including CBC, thyroid function, urinalysis, BUN, creatinine, serum calcium, and pregnancy test in females. 8
• Monitor lithium levels, renal and thyroid function, and urinalysis every 3-6 months during maintenance therapy. 8
• Lamotrigine has shown some efficacy in delaying depression recurrences but evidence is mixed. 7

Psychosocial Interventions

• The combination of pharmacotherapy and psychosocial interventions, including psychoeducation, cognitive behavioral therapy, and family interventions, is essential for both acute and maintenance treatment. 2
• Family-focused psychoeducation about symptom recognition, early warning signs of both depression and hypomania, and medication adherence optimizes long-term outcomes. 8

Critical Monitoring Parameters

• Schedule close follow-up within 1-2 weeks to reassess symptoms, verify medication adherence, and determine if mood symptoms are worsening, stable, or improving. 8
• Use structured rating scales like the Young Mania Rating Scale (YMRS) at each visit to objectively track any emerging hypomanic or manic symptoms. 8
• Assess for early warning signs of antidepressant-induced mood destabilization if antidepressants are used. 1

Prognostic Considerations

• Bipolar II with psychotic features may represent a different phenotype from non-psychotic Bipolar II disorder, requiring more intensive monitoring. 3
• The presence of psychotic features during depression, combined with antidepressant-induced mania history, indicates higher risk for future mood destabilization and requires aggressive mood stabilization. 2, 3