Abrupt cessation of heavy cannabis use can cause a withdrawal syndrome characterised by irritability, anxiety, insomnia, reduced appetite and restlessness. Recent reports have also described people in whom cannabis withdrawal immediately preceded the acute onset of psychosis.

To identify cases of psychosis associated with cannabis withdrawal.

We completed a systematic review of the literature, which comprised case reports, case series and other studies. We also searched a large electronic database of psychiatric healthcare records.

The systematic review identified 44 individuals from 21 studies in whom cannabis withdrawal preceded the development of acute psychosis. In the health record study, we identified another 68 people, of whom 47 involved a first episode of psychosis and 21 represented further episodes of an existing psychotic disorder. Almost all people were daily cannabis users who had stopped using cannabis abruptly. Individuals who continued to use cannabis after the acute psychotic episode had a much higher risk of subsequent relapse than those who abstained (odds ratio 13.9 [95% CI: 4.1 to 56.9]; χ2 = 20.1, P < 0.00001).

Abrupt cannabis withdrawal may act as a trigger for the first episode of psychosis and a relapse of an existing psychosis. Acute psychotic symptoms can emerge after the cessation, as well as following the use, of cannabis.

突然停止大量使用大麻会导致戒断综合症，其特征是易怒、焦虑、失眠、食欲下降和不安。最近的报告还描述了在精神病急性发作之前立即戒断大麻的人。

确定与大麻戒断相关的精神病病例。

我们完成了对文献的系统评价，包括病例报告、病例系列和其他研究。我们还检索了一个大型的精神科医疗记录电子数据库。

该系统评价从 21 项研究中确定了 44 名个体，其中大麻戒断先于急性精神病的发展。在健康记录研究中，我们确定了另外 68 人，其中 47 人涉及精神病的首次发作，21 人代表现有精神障碍的进一步发作。几乎所有人都是突然停止使用大麻的日常大麻使用者。在急性精神病发作后继续使用大麻的个体比弃权者随后复发的风险要高得多（比值比 13.9 [95% CI： 4.1 至 56.9];χ2 = 20.1， P < 0.00001）.

突然的大麻戒断可能会成为精神病首次发作和现有精神病复发的触发因素。急性精神病症状可能在停止使用大麻后以及使用后出现。