AN injury at 14 sparked the marijuana use of Brent Anthony Hamers, his lawyer told Warwick Magistrates Court yesterday.

Now 27, the Warwick man pleaded guilty to multiple drug-related charges, including possession of dangerous drugs and drug-driving, as well as a charge for stealing.

On probation when most of the offences occurred between February and July last year, the father of three had been seeking ongoing help, defence lawyer Kevin Rose said.

Mr Rose presented a letter from GP Dr Andrew Rees, which noted Hamers used marijuana in an attempt to relieve severe chronic neuropathic pain and help him sleep.

A psychologist also submitted a report which Mr Rose stated was incomplete due to Hamers failing to provide all necessary documents. The page Mr Rose did have explained Hamers was managing to utilise coping strategies other than marijuana and alcohol and was on track to addressing his drug issues.

"You've seen the letters from the doctors and psychologist, there does seem to be evidence that he's seriously addressing his cannabis issues,” Mr Rose said.

Magistrate Bevan Manthey acknowledged Hamers' effort during sentencing.

"He has used his time wisely to address real, significant issues,” he said.

Mr Manthey said imprisonment would satisfy the need for deterrence and for Hamers to continue addressing his issues.

Hamers was convicted on all counts, sentenced to a total of nine months imprisonment but was released on immediate parole. His driver's licence was disqualified for 12 months.

Mr Manthey warned Hamers if he reoffended during parole, he would be sent straight to jail.