dissents.
¶28 I dissent from the Court’s decision to vacate D.M.S.’s commitment. I conclude sufficient evidence exists in the record for the jury to find beyond a reasonable doubt that D.M.S. recently caused injury to others and to find to a reasonable medical certainty he did so because of a *266mental disorder. Section 53-21-126(l)(b), (d), MCA.
¶29 As stated by the Court, in a criminal case, a motion to dismiss for insufficiency of the evidence is only appropriate if, viewing the evidence in a light most favorable to the prosecution, no evidence exists upon which a rational trier of fact could find the essential elements of the crime beyond a reasonable doubt. Clark, ¶ 14; State v. Bomar, 2008 MT 91, ¶ 13, 342 Mont. 281, 182 P.3d 47; State v. Swann, 2007 MT 126, ¶ 16, 337 Mont. 326, 160 P.3d 511 (citations omitted). We review a district court’s denial of such a motion de novo, because evidence is either sufficient or it is not. Swann, ¶¶ 16-19. However, when considering the sufficiency of the evidence, this Court should not-as I believe it does in this case-substitute its judgment for that of the trier of fact because the trier of fact views the evidence firsthand, observes the demeanor of the witnesses, and weighs the credibility of each party. State v. Maetche, 2008 MT 184, ¶ 14, 343 Mont. 464, 185 P.3d 980; State v. Shields, 2005 MT 249, ¶ 20, 328 Mont. 509, 122 P.3d 421.
¶30 The Court vacates the commitment, concluding the evidence was insufficient to prove to a reasonable jury that D.M.S. is a threat to the community because of his admitted mental disorder. However, considering all of the evidence in a light most favorable to the State, it is clearly sufficient to establish that D.M.S.’s mental disorder causes him to be dangerous.
¶31 D.M.S. exercised his right to remain silent by refusing to speak with Dr. Mozer. Nevertheless, after reviewing the evidence available to him, Dr. Mozer testified that, in his expert opinion, D.M.S. was dangerous to the community even when he was in a controlled environment. In the structured setting of the state hospital, D.M.S. engaged in violence against other patients. Dr. Mozer also testified that D.M.S. was an alcoholic and alcohol caused a deterioration of his mental condition. A fair interpretation of Dr. Mozer’s testimony is that the deterioration of D.M.S.’s mental condition made him dangerous. The jury was entitled to interpret this testimony to the effect that D.M.S.’s mental disorder causes the violent outbursts and destructive behavior, not the consumption of alcohol.
¶32 Dr. Hill, a qualified mental health expert called by D.M.S., testified D.M.S. suffered a cognitive decline contributed to by alcohol abuse. She went on to confirm that, while in a controlled setting at the state hospital, D.M.S. attacked another patient at least once. She testified that D.M.S.’s mental disorder causes him to become violent if he does not get his way. She said D.M.S.’s mental disorder will *267predictably deteriorate further if left untreated and that he poses a risk to others.
¶33 Several times during the trial when things were not going his way, in the presence of the jury, D.M.S. spontaneously interjected comments, demonstrating anger as well as an inability to control himself. The jury witnessed these outbursts and was entitled to consider them in making its determination whether D.M.S.’s consumption of alcohol or his admitted mental disorder caused him to be a threat to others.
¶34 When one drinks to excess, one does not necessarily burn up vehicles. From the evidence of D.M.S.’s actions when he was sober, his actions at the trial, and the facts surrounding the arson, the jury was entitled to find that D.M.S.’s mental disorder, and not the consumption of alcohol, caused him to burn the vehicles at the trailheads.
¶35 I would conclude the jury was presented with more than sufficient evidence to find, as a matter of fact, D.M.S.’s mental disorder caused him to recently harm others and made him a danger to the community. I dissent.