Schizophrenia and other psychiatric matters may be triggered by cannabis use.

With states rapidly authorizing marijuana for medicinal and recreational use, physicians will be increasingly pushed to counsel patients on their frequency of use and dosage, as well as associated risks.

While there is no easy way to forecast which young people might grow mental health issues as a result of cannabis use, a family history of mental illness could suggest possible risk.

Some longer-term effects related with marijuana use include impaired memory and concentration, and reduced motivation. Researchers say when marijuana use starts to impair an individual’s health status or social or work-related functioning, he or she should be counseled to stop using marijuana or referred to substance abuse treatment providers.

Patients without mental health or substance abuse problems, who use marijuana recreationally or medicinally, can still value physician counsel.

Many new products contain varied ratios of THC and CBD in order to create exact euphoric and medicinal effects. Scientists recommend physicians be aware of what products their patients are using — as well as how much and how often — in order to best advise them on medicating and risks.

When inhaling marijuana via a vaporizer, the user absorbs up to 33% of the total cannabinoids. People who smoke or vape also experience the effects quickly, with intoxication setting in within 2 minutes and lasting 2-4 hours. The near immediate onset of the high allows users to titrate their dosing more effectively.

By comparison, when marijuana products are ingested orally, THC is absorbed inconsistently. Users typically experience the effects of THC about 2 to 4 hours after ingestion, and its effects last for 6 to 8 hours. People who ingest marijuana products often experience a more intense and longer-lasting effect. Given the important delay of intoxication, it is much stress-free to overdose and experience negative effects.