The potential psychological side effects are highly varied and depend on the quality of the cannabis, the way it is used, user experience with the drug, and also the patient's mood at the time of administration.

After consumption, a patient may experience euphoria which gradually changes to satisfaction, calm, and peacefulness. Other effects are: relaxation, laughing fits, increased appetite, great sensitivity to music and colors, changes in the perception of time and space, and laziness. A lack of reactivity can also be observed, particularly during the first hours after administration. Following inhalation, the first two hours are the most important. When resorting to oral ingestion, the first four hours are to be considered.

The changes in perception can generate fear, panic and confusion. In patients who do not feel well, the drug can induce an even worse negative reaction.

Daily consumption can affect memory capacity and concentration.

There have been reports of restlessness and insomnia.

Psychotic reactions may also occur, which can be recognized by the hallucinations they produce. Other side effects are tachycardia, orthostatic hypotension (when standing), headache, dizziness, the simultaneous feeling of cold and heat in feet and hands, reddened eyes, unresponsive muscles, dry mouth, etc.

When smoked, the drug irritates the airways and in the long term can lead to diseases such as bronchitis, pharyngitis, chronic obstructive pulmonary disease (COPD), or lung cancer.