**Core Concept**
Depression with spiritual or existential guilt, often presenting with feelings of worthlessness and hopelessness, requires a nuanced approach combining psychotherapy and pharmacotherapy.

**Why the Correct Answer is Right**
This patient is experiencing a form of depression known as "spiritual crisis" or "existential guilt," where an individual feels overwhelmed by their perceived moral failings. The presence of suicidal ideation necessitates a comprehensive treatment plan. Pharmacotherapy with antidepressants, specifically Selective Serotonin Reuptake Inhibitors (SSRIs), can help alleviate depressive symptoms. In conjunction with pharmacotherapy, a form of psychotherapy like Cognitive Behavioral Therapy (CBT) or Psychodynamic Therapy can be employed to address the underlying spiritual and existential concerns. The involvement of a spiritual guru may be a part of his coping mechanism, but its efficacy in treating depression needs to be evaluated.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because simply prescribing medication without addressing the patient's underlying spiritual and existential concerns may not lead to a complete resolution of symptoms.

**Option B:** This option is incorrect because referring the patient for counseling without considering the severity of his depression and suicidal ideation may not be sufficient.

**Option C:** This option is incorrect because only attaching him to the spiritual guru without any medical intervention may not address the patient's acute depression and suicidal ideation.

**Clinical Pearl / High-Yield Fact**
In patients presenting with spiritual or existential guilt, it's essential to maintain a non-judgmental and empathetic attitude while exploring their spiritual and existential concerns. This can help establish a therapeutic alliance and facilitate the treatment process.

**Correct Answer: C.** Consult the spiritual guru while providing appropriate medical intervention.