The first trials of thousands of lawsuits filed against Johnson & Johnson subsidiary Janssen Pharmaceuticals over its antipsychotic medication Risperdal have begun.

Plaintiffs maintain that the drug caused gynecomastia, a condition in which boys and men develop large breasts, and that Johnson & Johnson concealed the risk of developing the condition.

A jury awarded $2.5 million to the family of an autistic Alabama man who developed large breasts – size 46DD — after taking Risperdal for five years starting at age 8. At the time, Risperdal was not FDA-approved for use in children. The drug’s label only warned of a low risk for gynecomastia.

A Philadelphia jury in March found that Janssen was negligent in warning of Risperdal’s risks, but determined it was not the cause of the defendant’s condition. Beginning in 2002, at age 6, the now 19-year-old took Risperdal for several years to treat oppositional defiant disorder.

Evidence presented at that trial showed that the drug-maker hid data from doctors and parents that a much higher percentage of children were developing gynecomastia than the company admitted.

Due to the vast number of Risperdal lawsuits, a federal judicial panel formed a consolidated litigation in Pennsylvania. Seven other Risperdal trial dates have been scheduled.

Commonly known as “man boobs,” gynecomastia is believed to be caused by a dramatic increase in prolactin levels.

The FDA first approved Risperdal in 1993 for the treatment of schizophrenia. Its uses later expanded to include adult and adolescent bipolar disorder and autism spectrum disorders in children and adolescents. The drug is commonly used for off-label purposes such as the treatment of deficit hyperactivity disorder (ADHD), anxiety, sleep difficulties and depression.

In 2012, Johnson & Johnson reached a confidential settlement with a 21-year-old man who, according to his Risperdal lawsuit, underwent a mastectomy after growing breasts, something he said resulted in “severe psychological trauma.”

The mental anguish of being bullied and teased results in depression, anxiety and insecurity in young men already battling mental health issues. Mild cases of gynecomastia can be treated with liposuction, but more severe cases require a mastectomy.

A recent study found that the risk of Risperdal gynecomastia exists for both boys and older men.

Older men who used the drug had a 69 percent higher risk of developing the condition than nonusers, according to information presented at the American Association for Geriatric Psychiatry’s annual meeting in 2014. The study was based on a review of national health claims.

Risperdal remains one of the most frequently prescribed medications in the world.