Studies show that suicide rates increase more in spring than in any other season, a pharmaceutical company said on Tuesday.

"In spring, there is a tremendous pressure to be happy. The contrast between what we think we should feel... and what we may feel... can lead to feelings of depression," Pharma Dynamics spokeswoman Mariska van Aswegen said in a statement.

"People who are vulnerable to suicidal behaviour face more challenges when the weather warms and social interaction increases."

The latest studies suggest little correlation between mental well-being and warm weather.

The study "The Effects of Weather on Daily Mood: A Multilevel Approach" was done by three professors from universities in Scotland, Germany, and the Netherlands.

On average, 23 South Africans commit suicide each day.

Some psychologists maintain that the increase in sunlight may provide the energy needed for a depressed person to carry out a suicide.

Van Aswegen said people suffering from allergies and hayfever were also vulnerable.

"Headaches, sleeplessness and fatigue associated with allergies are all symptoms of depression as well.

"Studies also confirm that changes in allergy symptoms during low and high pollen seasons correspond to changes in patients' depression and anxiety scores."

Clinical depression is marked by a depressed mood most of the day and a loss of interest in normal activities and relationships.

Symptoms may include tiredness or loss of energy almost every day, significant weight-loss or gain, feelings of worthlessness or guilt, impaired concentration, insomnia or hypersomnia (excessive sleeping) and a diminished interest or pleasure in almost all activities.

If any of these symptoms continued for more than two weeks, Van Aswegen suggested seeking help from a mental health practitioner. She recommended exercising and getting eight hours sleep a day.

Major depression affects about one in three South African adults, 8.3 percent of adolescents and 2.5 percent of children.