Chemotherapy and Mood Swings: What to Expect and How to Cope

Chemotherapy can be associated with mood swings and emotional changes, such as feeling sad, anxious, irritable, or restless, and these feelings may fluctuate throughout the day. ^[1] These emotions vary from person to person and can occur during treatment, sometimes accompanied by fatigue or trouble relaxing. ^[2] Emotional distress can also be linked to worries about the diagnosis, treatment side effects, uncertainty, and feeling isolated, and in some cases may contribute to depression. ^[3]

Why Mood Changes Happen

• Treatment impact and stress: The physical effects of chemotherapy, pain, fatigue, and sleep disruption can strain emotional balance and heighten mood variability. ^[4] Fears about treatment, prognosis, and side effects may intensify these feelings. ^[5]
• Cognitive effects (“chemo brain”): Attention or memory changes can add frustration or irritability, and mood problems such as anxiety or depression can interact with these cognitive symptoms. ^[6] Managing underlying issues like fatigue, insomnia, and low mood can improve cognitive and emotional function. ^[7]

Signs to Watch For

• Frequent shifts between sadness, anxiety, irritability, or feeling “on edge.” ^[2]
• Feeling exhausted or unable to relax, with emotions rising and falling across the day. ^[8]
• Persistent low mood, loss of interest, or hopelessness that interferes with daily life, which may signal depression and deserves prompt attention. ^[9]

Practical Coping Strategies

• Open communication: Talk with trusted family or friends about how you feel; honest conversations can reduce isolation and improve mutual understanding and support. ^[1] Sharing emotions with close contacts during treatment is encouraged and can provide comfort. ^[2]
• Ask for help: Accept practical help from others and delegate stressful tasks when possible to lower daily strain. ^[8] Reaching out to your care team early about symptoms enables tailored support. ^[10]
• Relaxation techniques: Try simple breathing exercises slow deep inhale, slow exhale imagining tension leaving to calm the nervous system and ease distress. ^[11] Regular relaxation can help maintain emotional balance alongside medical care. ^[12]
• Stay connected and active: Engaging in social, community, or spiritual activities, and recalling positive memories, can lift mood and combat fatigue. ^[10] Gentle physical activity, if approved by your care team, may improve energy, cognition, and mood. ^[13]
• Address contributors: Treating fatigue, insomnia, anxiety, and depression can lessen both cognitive fog and mood swings; physical exercise is encouraged when safe. ^[7]

When to Seek Professional Support

• Psychosocial care is part of cancer treatment: Routine screening for distress is recommended in cancer care settings, and many people benefit from talking with mental health professionals. ^[14] Despite recommendations, many do not receive care, so self-advocacy asking your team for screening and referral can be important. ^[15]
• Support groups: Connecting with others facing similar experiences (in person or online) can provide understanding, coping tips, and hope. ^[16] Cancer-specific groups and family support programs are widely available through clinics and advocacy organizations. ^[17]

Helpful Resources

• National and hospital-based education programs offer guidance on managing emotions during adjuvant or neoadjuvant therapy, emphasizing communication, help-seeking, and coping skills. ^[1] These resources also highlight common mood changes and practical steps for support during advanced treatment. ^[2] Guidance materials similarly encourage sharing feelings, accepting help, and using relaxation to stabilize mood. ^[8]