Possession of a controlled substance in Texas refers to the unlawful custody, care, or control over drugs categorized into various penalty groups. (24) "Lawful possession" means the possession of a controlled substance that has been obtained in accordance with state or federal law.To get a possession charge dismissed, provide evidence of unlawful search or demonstrate a lack of possession knowledge. Houston Possession of a Controlled Substance Lawyer: Greco Neyland, PC offers strategic defense against drug possession charges. To be successful, the State must prove your state of mind in its drug possession case against you. Prove that the controlled substance is considered illegal in Texas or was unlawful to possess in this instance;. Drug possession convictions in Houston can come with a license suspension. Unlawful Searches Are Common In Drug Arrests. Arrested for suspicion of possession of a controlled substance? In Texas, attempted possession of a controlled substance is taken seriously.