Methamphetamine-induced tic disorder: This is the most likely diagnosis given the context of meth use, as methamphetamine is known to cause or exacerbate tic disorders due to its effects on the brain's dopamine system.

Tourette syndrome: A neurodevelopmental disorder characterized by repetitive, stereotyped, involuntary movements and vocalizations called tics. Meth use could potentially trigger or worsen symptoms in someone predisposed to Tourette syndrome.
Anxiety disorder: Methamphetamine use can lead to significant anxiety, which might manifest with physical symptoms that could be mistaken for tics, such as tremors or restlessness.
Akathisia: A movement disorder characterized by a feeling of inner restlessness and a compelling need to be in constant motion, often seen as a side effect of antipsychotic medication but can also be associated with substance use, including methamphetamine.

Neuroleptic malignant syndrome (NMS): A life-threatening neurological disorder most often caused by an adverse reaction to neuroleptic or antipsychotic medication, but it can also be triggered by other substances, including methamphetamine. Early recognition is crucial due to its high mortality rate.
Serotonin syndrome: A potentially life-threatening medical condition resulting from an excess of serotonin in the central nervous system, which can occur with the use of certain medications or substances, including methamphetamine, especially when combined with other serotonergic agents.
Stroke or transient ischemic attack (TIA): Methamphetamine use is associated with an increased risk of stroke and TIA due to its effects on blood pressure and vasculature. Sudden onset of tics or movement disorders could be a manifestation of a cerebrovascular event.

Huntington's disease: A rare, inherited disorder that causes progressive damage to the brain, leading to physical, cognitive, and psychiatric problems, including movement disorders. While rare, it's essential to consider in the differential diagnosis of any movement disorder.
Wilson's disease: A rare genetic disorder characterized by excessive accumulation of copper in the body, particularly in the liver, brain, and other vital organs. It can cause a variety of neurological symptoms, including movement disorders.
Sydenham's chorea: A rare neurological disorder occurring in some cases of rheumatic fever, which can cause rapid, involuntary movements, primarily affecting children and adolescents. It's less likely in the context of meth use but should be considered in the appropriate demographic and clinical context.