Mould and mental health

The retrieved studies do not directly test whether indoor mould causes depression or anxiety, but they document mechanisms that plausibly link the two.

The evidence here focuses on respiratory and allergic outcomes, not mental health. A 2018 systematic review found sufficient evidence that indoor mould causes childhood asthma, with adjusted odds ratios around 1.3 to 1.7 for asthma development [1]. A 2012 study showed that classroom exposure to Alternaria mould was associated with decreased nasal patency in children, independent of allergic conditions [2]. A pilot study found that people living in moisture-damaged homes had elevated white blood cell counts, higher release of inflammatory cytokines like IL-1β and IL-8, and increased expression of innate immune receptors TLR-2, TLR-4, and Dectin-1 [3]. That is a primed inflammatory state.

Chronic inflammation is a well-documented pathway into mood disorders. Outside this retrieval, systemic inflammation is linked to depression through cytokine signaling that reaches the brain, alters neurotransmitter metabolism, and activates the kynurenine pathway. The evidence here shows that mould exposure triggers exactly that kind of systemic inflammatory response [3]. A 2025 rodent study in this retrieval found that chronic stress induced depressive behaviors and region-specific neuroinflammation in olfactory circuits, with correlations between glial activation and aversion behavior [5]. That is not mould, but it shows a mechanism by which environmental triggers of neuroinflammation can produce mood changes.

The gap is large. No study in this retrieval measured depression or anxiety outcomes in people exposed to indoor mould. The respiratory evidence is strong [1, 2, 4], the inflammatory mechanism is documented [3], and the link from inflammation to mood is established in other contexts. But the direct epidemiological evidence tying mould to mental health outcomes is absent from this search.

My call: the evidence supports a plausible mechanism from mould exposure through inflammation to mood disturbance, but no study here directly tested that link. Confidence: low for a causal connection, moderate for the inflammatory mechanism itself.