Yes. Symptoms of overdose may include sleepiness, confusion, disorientation loss of coordination, dizziness, fainting, falls, as well as fast or slow heartbeat. You should seek immediate medical attention if you experience cannabis induced chest pain, panic attacks, loss of contact with reality, or seizures. The risk of overdose becomes much higher if cannabis is combined with alcohol, certain medications (e.g. opioids or benzodiazepines), or illegal drugs.