Ask Your Pharmacist

December 19, 2019

Every winter I struggle with low mood. I’ve heard people talk about Seasonal Affective Disorder (S.A.D.) and light box therapy. Can you provide information with about this condition and how to treat it?



Thank you for the timely question! A lot of us struggle with low mood at this time of year. I personally have battled with S.A.D. as well as depression and anxiety for the better part of the last 20 years. Today, although it’s something I am always mindful about, it no longer has control over me. I thought I might share some therapies below that are supported by science.  

What is Seasonal Affective Disorder (S.A.D)?

A diagnosis of S.A.D. is considered when someone experiences a depressed mood for two consecutive winters, with no depressed mood during spring and summer. S.A.D. usually occurs during the same time each year and is thought to be caused by changes in the level of exposure to sunlight.

What are some treatments supported by science?

Prescription medications (i.e. Selective Serotonin Reuptake Inhibitors (SSRIs) and bupropion XL) These medications may be prescribed by your doctor or nurse practitioner to be used along with counselling with a licensed psychologist.   Antidepressants work to increase chemicals in the brain (i.e. serotonin) that scientists believe are important in regulating mood. Side effects with these medications usually occur at the beginning of therapy and begin to improve around day seven. By two weeks on medication, people begin to have improved sleep, appetite, and other physical symptoms. It may take up to four to six weeks, before noticeable improvements in mood occur.

Vitamin D3 (cholecalciferol) Speak with your pharmacist before starting any new prescription or over-the-counter medication to ensure there are no drug interactions. A suggested starting dose is 1000 international units (IUs) or 25 mcg daily. D drops are available as liquid vitamin D3 1000 IU/drops. Doses may be increased by 1000 IU weekly up to 5000 IU daily. Larger doses are generally taken only for the duration of the winter season, then are decreased during months with longer hours of daylight. Patients on higher doses of vitamin D3 may experience insomnia. This can be minimized by talking the medication in the morning. Higher doses are also associated with diarrhea.  

Light therapy or Phototherapy Evidence exists that daily exposure to bright light may be an important add-on therapy for treatment of S.A.D. Light therapy is believed to provide antidepressant action by increasing the amount of serotonin and other mood related chemicals in our brain. The best form of light therapy is to get outside daily and enjoy the outdoors; however, this is not always possible during Canadian winters. An alternative is to use a light box. A light box is a fluorescent source which provides a daily exposure to bright light. The dose of light provided varies in intensity, spectrum (soft white to blue enhanced light), exposure duration, time of administration (AM versus PM). The standard dose of light is 10,000 lux for 30 minutes per day during early morning for at least six weeks. Side effects may include headache and eye strain.  

Some other tips I’ve learned along the way: No one knows you better than you. Be watchful.  Some of my personal signs and symptoms are: sleeping more than usual but not rested, withdrawing from my friends and usual social habits, not going to the gym, experiencing poor appetite.

Have a plan. Identify a support network that you can go to if you begin to feel down. This may include friends or family, but ideally also a qualified therapist. Avoid triggers such as alcohol, illicit drugs, and situations you know cause you anxiety. Journal your thoughts and feelings daily. Keep a healthy diet (lower in carbohydrates). Laugh. Laughter IS the best medicine.  Surround yourself with the right people and avoid triggers. Don’t stop your medication or skip your therapy appointments even if you are feeling better. Lastly, what you are feeling is real.  There is no shame in depression. Let’s normalize S.A.D. and depression by talking about it openly.

Dr Kevin Duplisea (PharmD BSc. Pharm, BSc. ACPR) is a pharmacist at Sharp’s Corner Drugstore in Sussex, New Brunswick. His opinions expressed in this newspaper are published for educational and informational purposes only, and are not intended as a diagnosis, treatment or as a substitute for professional medical advice, diagnosis or treatment. Send your questions to