Antidepressant-Induced Mania/Hypomania: Immediate Discontinuation Required
This patient is experiencing antidepressant-induced mania or hypomania from venlafaxine, which is a recognized and potentially serious adverse effect of SNRIs—the most urgent issue is to immediately discontinue the venlafaxine and evaluate for bipolar disorder. 1, 2
Why This is the Primary Concern
The clinical presentation is classic for antidepressant-induced mood elevation:
- Racing thoughts and inability to "shut off" the mind indicate accelerated thought processes characteristic of mania/hypomania 1
- Pressured speech is a cardinal symptom of manic episodes 1
- Hyper-focused, goal-directed activity (spending hours writing to congressmen about military budget) represents the increased goal-directed behavior seen in mania 1
- Insomnia in this context is not simply a side effect but part of the manic syndrome with decreased need for sleep 1
- Three-week timeline aligns with typical onset of behavioral activation/agitation from SNRIs 1, 2
The Critical Distinction
This is not simply insomnia as a side effect of venlafaxine (which does occur in 18% of patients) 1, 2. The constellation of symptoms—racing thoughts, pressured speech, and excessive goal-directed activity—indicates a manic or hypomanic episode, which is explicitly listed as an "uncommon but potentially serious adverse effect" of SNRIs including venlafaxine 1.
Immediate Management Steps
Discontinue venlafaxine immediately rather than tapering, given the severity of symptoms and relatively short duration of use (3 weeks). While gradual tapering is typically recommended to avoid discontinuation syndrome, the acute psychiatric emergency of mania takes precedence 2.
Evaluate for underlying bipolar disorder. This presentation strongly suggests the patient may have bipolar disorder that was misdiagnosed as unipolar major depressive disorder. Antidepressant monotherapy can unmask or precipitate manic episodes in patients with bipolar disorder 1.
Monitor closely for the next 1-2 weeks as symptoms should resolve after discontinuation. If symptoms persist beyond medication washout, this confirms an underlying bipolar diagnosis rather than pure drug-induced mania 1.
Common Pitfall to Avoid
Do not attempt to manage the insomnia symptomatically while continuing venlafaxine. The insomnia here is part of a manic syndrome, not an isolated side effect. Treating it as simple insomnia while continuing the offending agent will allow the mania to progress and potentially worsen 1.
Future Treatment Considerations
If bipolar disorder is confirmed, the patient will require mood stabilizers rather than antidepressant monotherapy. If this was purely drug-induced and resolves completely, alternative antidepressants with lower risk of behavioral activation (such as SSRIs at lower doses with careful monitoring) might be considered, though consultation with psychiatry is warranted given this reaction 1.
The FDA label explicitly warns that venlafaxine can cause "behavioral activation/agitation, hypomania, mania" and emphasizes the need for patient monitoring, particularly in the early weeks of treatment 2. This patient's symptoms represent exactly this warned complication.