Texas' cannabis companies could see their business opportunities grow under a bill filed Thursday by the Fort Worth lawmaker who helped create the state's first medical marijuana program.

Rep. Stephanie Klick, R-Fort Worth, wants to add multiple sclerosis, spasticity and all types of epilepsy to the list of medical conditions that qualify Texans to buy a cannabis-based medicine. The program is now restricted to Texans with intractable epilepsy.

Her bill would also decrease the number of doctors who need to sign off on a patient's use from two to one and establish a medical cannabis research program.

Rep. Stephanie Klick authored the bill that created Texas' Compassionate Use Program. Now, she's filed a bill that would add more qualifying medical conditions and start a new research initiative. (Tom Fox / Staff Photographer)

Klick authored the Compassionate Use Act in 2015 that required the Texas Department of Public Safety to issue licenses to at least three medical marijuana companies by September 2017. Licensees can grow marijuana, produce cannabis-based medication and sell it to patients. The state agency started a registry of doctors who treat and can recommend cannabis to Texans with epilepsy.

Klick, a registered nurse, pushed for the program after hearing from a constituent who had a granddaughter with severe seizures.

Texas lawmakers are considering numerous cannabis-related bills this session. Some, including Klick's, would expand the qualifying medical conditions for the state's Compassionate Use Program. Others would reduce criminal penalties for possession of marijuana or legalize hemp, another variety of the cannabis plant that's low in THC.

Three companies are licensed to grow and sell the cannabis-based medication: Surterra Texas grows and operates in Austin, but its parent company is based in Atlanta. Miami-based Knox Medical, licensed as Cansortium Texas, grows and manufactures in Schulenburg, a rural town about 100 miles northeast of San Antonio. Compassionate Use, founded and led by a group of Texans, operates in Manchaca, just outside Austin.

But unlike other businesses, the three companies face a unique challenge: Their market is restricted to a small pool of Texans. There are between 102,000 and 136,000 Texans with intractable epilepsy, according to the Epilepsy Foundation of Texas.

The medication is made from the marijuana plant but is low in THC, the compound that gives marijuana users a high, and rich in cannabidiol, or CBD. Most of the products are sold as bottles of drops that are taken under a person's tongue. Prices range from about $95 to $340, depending on the company and the bottle's size.