A California doctor prescribed cannabis cookies to a 4-year-old. Now, he's lost his license to practice -- but not why you probably think.

The Hollywood physician was consulted in 2012 by the 4-year-old boy's father, who was already one of the doctor's medical marijuana patients. The father was concerned because the preschooler had trouble sitting still in school and was having tantrums -- behavior which the school said was unacceptable.

After an appointment that lasted a half hour or less, the 69-year-old doctor diagnosed the boy with attention deficit hyperactivity disorder (ADHD) and bipolar disorder -- two serious conditions that require lifelong treatment and have serious implications for a patient's future.

He neither witnessed any tantrums from the child nor spoke with anyone at the school about the child's behavior -- and seemed to glean the diagnosis mostly out of thin air. He quickly prescribed the cannabis-laced cookies -- but let the father determine the dose without any kind of recommendation.

The marijuana cookies did help control the child's tantrums -- and the situation only came to light after the father approached the school nurse about giving the child a second dose during the day, with his lunch. Police eventually got involved and an investigation was launched.

Ultimately, however, the Medical Board didn't quibble with the fact that the doctor prescribed marijuana to a 4-year-old. Rather, the Board took issue with the way the doctor diagnosed the patient on such little information, with an insufficient examination. The Board also faulted the doctor for failing to follow up with the patient and a failure to keep adequate records. Ultimately, the doctor's license was revoked on Jan. 4, 2019, although he is still practicing under a temporary injunction by a San Francisco judge.

If you're a physician, cases like this are a reminder that documentation is everything. If you make a diagnosis, you need to have clearly convincing evidence in your files that can show the path you took to arrive at that diagnosis. Sometimes that means doing a lot of extra testing or legwork -- but that's better than losing your license. Don't let your license to practice medicine be taken because you relied on your instincts and years of experience alone -- even if you're convinced you are right.