Hour of the Wolf

1/ Wikipedia says Hour of the Wolf is part of a trilogy with Shame and The Passion of Anna. I see it as a companion-piece to Persona. 
2/ At the centre of Persona is Elisabet, an actress who casts off her role as a wife and as a mother, withdraws into herself and refuses to speak. In Hour of the Wolf, there is also an artist—Johan Borg is a painter who lives on a remote island and struggles with his own demons. In Persona, Elisabet slowly takes over Alma, her nurse—the 2 women merge into 1. In Hour of the Wolf, Johan slowly loses grasp of reality, becoming more and more insane, and after a while his loving wife Alma also starts to see his demons.   
3/ Both films remind us they’re a film: Persona starts with a film projector and a series of images like cartoons and silent films; Hour of the Wolf starts with the voice of Ingmar Bergman, over the opening credits, giving instructions to his crew. However, Hour of the Wolf creates the illusion of a real story by stating that it’s based on Johan’s diary and his wife’s account of what happened. Then Alma speaks to the camera as though telling the story to a documentary filmmaker. 
4/ Robin Wood points out, in his essay “The World Without, the World Within”: 

“… In view of his often expressed admiration for Fellini the film’s close relationship in subject, structure and method to Giulietta degli Spiriti is perhaps not surprising, any more than is its complementary self-sufficiency (Bergman clearly needn’t fear accusations of plagiarism). What is surprising is Bergman’s use of the traditions of the American horror film, from Whale and Browning to Hitchcock. Not only does the Birdman (as Tom Milne has pointed out) bear an unmistakable resemblance to Lugosi’s Dracula, but the face of Baron von Merkens, especially when photographed from below, as at the dinner party, distinctly recalls in its contours Karloff’s original Frankenstein creation. The minuscule but apparently human Tamino in the Birdman’s ‘Magic Flute’ performance recalls Ernest Thesiger’s homunculi in The Bride of Frankenstein. The general framework, with an outsider being initiated into a close-knit, isolated and highly abnormal society, and especially the ending, where in the darkness and mud its members hideously exact a communal vengeance, suggest Freaks. The old woman who peels off her face to reveal a decomposing skull and gaping eye-sockets evokes at once the 2 Wax Museum films and Mrs Bates in Psycho. The pecking and jabbing Birdman suggests both Psycho and The Birds, and the shot of von Sydow passing through a corridor thick with sparrows and other wild birds looks like overt reference (hesitate as one is to associate such seemingly incompatible directors). There are further more generalized references: the castle interiors, for instance, especially in the later sequences, are strongly reminiscent of Hollywood Gothic, from Whale to Corman; the ‘cannibal’ family suggests vampires, particularly in the way the lips of the father-figure’s huge mouth draw back, and there is a reference to their ‘fangs’ during the nightmarishly edgy and disquieting dinner-table conversations.” 

5/ Hour of the Wolf can also be seen as a companion-piece to Through a Glass Darkly, in which it’s not a male character but a female character who struggles with mental illness—Karin, played by Harriet Andersson, has schizophrenia. The sane, loving and patient husband in the film is played by Max von Sydow, who in Hour of the Wolf sees demons and can’t distinguish between reality and hallucinations. In both films, the loving spouse can do nothing to help. 
6/ Robin Wood argues: 

“Some have seen those demons as representing the artist’s imaginative creations over which, Frankenstein-like, he loses control; or as the side of his personality out of which his art develops. Nothing could be further from the truth. The point is made quite unequivocally that the demons are inimical to artistic creation—their emergence in the 1st stretches of the film corresponds to a decline in Johan’s art. What is more, their destruction of him as an artist is closely paralleled by their destruction of his marriage relationship.” 

7/ In a section about Wild Strawberries in the essay “Sexual Themes in the Films of Ingmar Bergman”, Richard A. Blake, S. J. writes: 

“[In a dream], [Isak Borg] is asked to examine a woman whom he pronounces dead. With that she opens her eyes and laughs derisively in his face. He has so drawn away from woman, from the source of life, that he has lost his ability even to distinguish life from death…” 

There’s a similar scene in Hour of the Wolf—Johan walks to the naked corpse of his former lover Veronica Vogler and touches her body, then she wakes up and laughs in his face. Does it happen? Do the people in the castle even exist? That doesn’t matter. The point is the humiliation, as in Wild Strawberries. However, if in Wild Strawberries, it only shows that Isak Borg, despite his career success, is a failure as a person, and little more than a dead man, in Hour of the Wolf, the scene culminates in Johan’s ultimate humiliation—everything is shattered, and Johan now knows he cannot defeat the destructive forces within him. He must surrender.