Case Study 2: When Mood Improved but Motivation and Energy Did Not

Reason to come to PPI: The antidepressant helped the sadness—but the patient still did not feel like themselves.

A patient came to Personalized Prescribing after treatment with an SSRI antidepressant.

The medication had clearly helped one part of the problem:

Their mood had improved.

However, the patient continued to experience:

• Very little motivation
• Low energy
• Little interest in activities
• Reduced enjoyment of life
• Difficulty getting started
• A feeling of being emotionally “flat” The patient was no longer as depressed, but they still did not feel well.

This raised an important question: Why had serotonin treatment improved mood without restoring motivation and interest?

PPI Looked Beyond Serotonin Alone

SSRIs work primarily by increasing serotonin signaling.

That can be very helpful for symptoms such as:

• Low mood

• Anxiety

• Worry

• Emotional distress But serotonin also interacts with other brain chemicals, particularly:

• Dopamine

• Norepinephrine These chemicals are important for:

• Motivation

• Energy

• Reward

• Interest

• Concentration PPI’s pharmacodynamic assessment identified a genetic pattern associated with higher activity or expression of the serotonin 5-HT2C receptor, encoded by the HTR2C gene.

HTR2C — When More Serotonin May Also Affect Dopamine

HTR2C is one of the receptors that responds to serotonin.

In some brain circuits, activation of the 5-HT2C receptor can reduce dopamine and norepinephrine release.

A simple way to think about it is:

1. SSRI increases serotonin signaling
2. More serotonin activates serotonin receptors
3. Strong 5-HT2C signaling may place more restraint on dopamine pathways
4. Mood may improve, while motivation and reward remain reduced

This provided one possible biological explanation for the patient’s experience.

It did not prove that HTR2C caused the symptoms, but it helped the pharmacist understand why a serotonin-only strategy might not be addressing the patient’s full symptom pattern.

The Patient’s Symptoms Told the Same Story

The patient’s treatment response was important.

The SSRI appeared to help:

• Mood

• Emotional distress But it did not adequately improve:

• Motivation

• Energy

• Interest

• Pleasure These remaining symptoms suggested that the patient’s treatment might need to support:

Dopamine and norepinephrine as well as Serotonin

A Broader Medication Strategy

Rather than abandoning the benefit the patient was receiving from serotonin treatment, the PPI pharmacist recommended discussing a combination of Sertraline and Bupropion with the patient’s treating clinician.

The reasoning was straightforward.

Sertraline- Primarily supports the Serotonin system and may continue to help with mood and anxiety symptoms.

Bupropion- Works mainly through Dopamine and norepinephrine pathways which are more closely involved in:

• Motivation

• Energy

• Interest

• Reward

• Concentration The strategy therefore became:

• Continue supporting serotonin

• Add support for dopamine and norepinephrine Address a broader range of the patient’s symptoms

What Happened Next?

After the medication plan was implemented by the treating clinician, the patient’s response was dramatic.

At follow-up, the patient described a major improvement in:

• Motivation
• Energy
• Interest in everyday life
• Overall wellbeing What had previously felt like an incomplete antidepressant response became a much more meaningful recovery.

The patient described the difference as: “Magical.”

For PPI, however, the important lesson was not that one particular combination will work for everyone.

It was that: Improved mood does not always mean that all of the brain systems involved in depression have been adequately treated.

Why This Case Matters

A conventional approach might have concluded: “The SSRI is working because the patient’s mood has improved.”

But the patient was still experiencing significant symptoms affecting daily life.

PPI looked at the fuller picture:

• What symptoms improved?
• What symptoms remained?
• Which neurotransmitter systems may be involved?
• What did the patient’s pharmacodynamic genetics suggest? A more individualized treatment strategy

Serotonin and Dopamine Need to Work Together

This case also demonstrates an important principle.

Brain chemicals do not work independently.

Increasing one neurotransmitter can influence another.

For this patient Serotonin treatment improved mood but Motivation and reward remained poor

PPI’s assessment suggested that stronger HTR2C-related serotonin signaling might be one factor influencing dopamine-related pathways.

The pharmacist therefore considered a treatment strategy that supported both:

Serotonin for mood and Dopamine and norepinephrine for motivation and energy

The Takeaway

The goal of antidepressant treatment is not simply: “Is the patient less sad?”

A better question is: “Has the person recovered across mood, energy, motivation, pleasure, concentration and everyday functioning?”

This is why PPI considers:

• Symptoms
• Medication history
• Pharmacokinetic genetics
• Pharmacodynamic genetics
• The way different neurotransmitter systems interact A more complete approach to personalized prescribing

Important Note

This is an individual patient experience and should not be interpreted to mean that HTR2C testing can reliably predict SSRI response or that sertraline plus bupropion is appropriate for everyone. Evidence for HTR2C and many other pharmacodynamic genes is still developing. PPI considers these findings as supportive information alongside the patient’s symptoms, treatment history, other genetic findings and clinical judgment. The treating healthcare professional remains responsible for medication decisions.