'Teen Mom' Amber Portwood -- Police Report Reveals a Slew of Prescription Pills

TMZ has obtained a police report that reveals new details about Amber Portwood's arrest last week -- turns out the controlled substances she was busted for were a variety of prescription pills ... most of which she couldn't produce prescriptions for.

As TMZ first reported, the "Teen Mom" star was popped back on December 19 on the possession charge as well as failing to provide a urine sample (which is part of her probation).

According to an affidavit given by Sgt. John Branson of the Anderson Police Department, the probation department visited Amber's home on December 16 because she had missed her probation appointment that day. Sgt. Branson says the probation officers found Portwood to be "very groggy."

Sgt. Branson goes on to explain the probation officers found a number of prescription pills (all mixed together in one bottle) and Portwood could not provide a script for majority of them ... at one point saying "her housekeeper throws all that kind of stuff away."

The officers later determined Portwood had 32 Hydrocodone pills, 6 Soma pills, 2 of another muscle relaxer, 3 of a different kind of Hyrdocodone, and then 1 pill they were unable to identify.