来自大麻的大麻，大麻苜蓿大麻是美国最常用的非法物质，在那里它仍然是法律辩论的争议题目。大麻有许多俚语名称，如锅，杂草和草。据国家滥用药物滥用研究所（NIDA），2007年每天近6000人试过大麻;并且，特别关注的是，超过62％的人未满18岁，这表明大麻在青年中继续进行了实验1。在这种物质中的400种化学物质中，Delta-9-四氢呋喃（Thc）负责大麻对大脑的影响。

Brain Effects

Upon inhaling marijuana, THC quickly gets transported from the respiratory system to the circulatory system and enters the blood.因此，血液将THC传输到大脑以及整个身体的其他地方。大脑的不同区域具有不同量的受体（用于大麻素）的神经元（脑神经细胞），其受THC与THC化学物质结合的影响;例如，具有多种这些受体的区域包括思维能力和浓度，感官感知以及时间的感知，记忆区域，娱乐和协调。

Short-Term Effects

MDMA的副作用

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第一次吸烟大麻之后几乎立即开始效果开始，可能持续两三个小时。口腔中的灼热感，喉咙干燥，血液的眼睛和增加的食欲是常见的。此外，与大脑区域受影响最大，短期影响可能包括：

• impairments in thinking
  
• problem-solving
  
• judgment
  
• comprehension
  
• 以及短期记忆受损

Time perception is altered and behaviors become limited due to impaired speech, concentration and coordination abilities. Sensory perception becomes distorted in terms of vision, hearing and touch. Physiologically, marijuana lowers blood pressure while increasing heart rate by 20 to 100 percent, which can last up to three hours. This drop in blood pressure, combined with an increased heart rate, is serious because, as the NIDA reports, a person smoking marijuana has four times the risk of experiencing a myocardial infarction (heart attack) within the first hour after inhalation. Moreover, while this substance is known for its euphoric state or sleepiness, it also can produce anxiety, paranoia with hallucinations or panic attacks.

长期影响

Chronic use of marijuana may produce multiple health problems later on in life beyond addiction to the substance itself. For example, chronic use is associated with high scores for anxiety and depression, with increased suicidal thinking patterns as well as the diagnosis of schizophrenia.Another important long-term effect is how THC acts on the immune system, that is, it decreases the function of the immune system, which may leave you more susceptible to frequent illnesses and infections.在呼吸效应方面，大麻比烟草更有效，因为作为奈达州，致癌性质比烟草更多的致癌性能更多;因此，它可能会增加肺癌或至少增加对频繁肺感染或阻塞气道条件的易感性的可能性。性功能障碍也可能是一个长期效果。