He's been under so much pressure lately he's gone a little loopy.
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Cantonese (chi1 sin3; 黐 means 'sticky / stuck'). The image is wires that have stuck or crossed inside the head. Common in HK films and TVB dramas; in Mandarin contexts use 神经 or 疯了 instead.
memory
Think of an old switchboard with 'crossed lines' - that's literally what 黐线 means: your mental wires got tangled.
